Brazing Graphite to Metals - Platinum Metals Review

PLATINUM METALS REVIEW 

A quarterly survey of research on the platinum metals and of 

developments in their applications in industry 

VOL. 11 OCTOBER 1967 NO. 4 

Ruthenium Oxide Glaze Resistors 

Cobalt-Platinum Alloy Magnets 

The Platinum Metals in Fuel Cells 

Further Expansion in Platinum Production 

The Platinum-Molybdenum System 

Contents 

Electron Configuration and Crystal Structure of Platinum Metal Alloys 

Brazing Graphite to Metals 

The Structure of Supported Platinum Catalysts 

Thc Platinum Metals in Catalysis 

Iridium Coatings in Ion Engines 

Carbonyl Halide Complexes of the Platinum Metals 

Performance of Platinised Titanium Anodes 

Abstracts 

New Patents 

Index to Volume 11 

Communications should be addressed to 

The Editor, Platinum Metals Revimv 

Johnson, Matthey & Co., Limited, Hatton Garden, London, E.C.1

Ruthenium Oxide Glaze Resistors 

NEW SCREEN PRINTING PREPARATIONS 

FOR THICK FILM CIRCUITRY 

By G. S. Iles and Miss M. E. A. Casale, B.s~. 

Research Laboratories, Johnson Matthey & Co Limited 

The rapid deoelnpment of thick jlrn 

integrated circuits has created a need for 

preparations that will provide resistor 

Jilrns on a variety of substrates. In the 

decelopment of the new rangp of 

rnateriuls described in this urticle 

adimntagr has bern takpn ofthr complex 

rnrrhanisrn of conduction through 

ruthenium dioxide. 

The past few years have witnessed mounting 

interest in integrated circuits and there is now 

little doubt that within the next decade a 

substantial proportion of electronic equip- 

ment will be based on them. 

Conventional circuits are normally as- 

sembled from discrete components by solder- 

ing them on to a printed circuit board. In 

integrated circuits, on the other hand, the 

circuit elements are deposited as films on to 

substrates, a number of which are often 

assembled together. It was first believed that 

vacuum deposition was the ideal technique 

for producing these circuits, but within the 

past year silicon integrated circuits and, to a 

lesser extent, thick film circuits, have gained 

considerable ground. Here the elements and 

their connections are applied as pastes to the 

substrate by screen printing and subsequent 

firing. While the circuits so produced are 

sometimes bulkier than their thin film 

counterparts, they have the advantage of 

simpler and well-established manufacturing 

techniques, greater versatility in manufacture 

and fewer problems in making connections. 

Silver and gold preparations capable of 

being screen printed have been available for 

Platinum Metals Rev., 1967, 11, (4), 126-129 126 

many years for discrete component manu- 

facture, and these are now employed in 

thick film integrated circuit production for 

connections and interconnections. Probably 

the most important new requirement for 

integrated circuits was a preparation capable 

of producing resistive films. This problem 

has been approached by developing suspen- 

sions, usually of powdered glaze (frit) and 

powders of one or more noble metals dis- 

persed in an organic medium. After screening 

to the substrate, the preparation is fired to 

burn away the organic material, fuse the 

glaze component and complete any other 

reactions necessary. By varying the composi- 

tion, a variety of different film resistivities can 

be produced but if close limits of resistance 

are required, they can be achieved by removal 

of part of the resistive film after firing. 

Until recently the majority of the resistive 

preparations available required a temperature 

of 700°C or above, this high firing tempera- 

ture being necessary to complete reactions 

within the preparation. This not only im- 

posed the necessity of very close control of 

furnace atmosphere and of the firing cycle, 

but also limited the choice of substrate to 

materials such as high-alumina ceramics 

capable of withstanding this firing tempera- 

ture. High surface finish of the substrate is 

necessary for this work, and mica and most 

glasses, which inherently have high surface 

finishes, were ruled out. 

Against this background the Johnson 

Matthey Research Laboratories have de- 

veloped glaze resistor preparations based on 

ruthenium dioxide. The objective was an ink 

incorporating a glaze based on a fully-reacted

One of the new Johnson 

Matthey preparations based 

on ruthenium oxide has been 

used in the production of these 

resistor plates by silk screening 

and $ring. The substrate was 

mica, which required no sur- 

face treatment. One of the 

assembled but unencapsulated 

circuits is also shown in the 

photograph. 

preparation that would be far less dependent 

on firing conditions than those hitherto 

available. To be viable the material had to 

satisfy three other conditions : 

(I) The metal/glaze system had to be 

capable of producing a wide range of 

resistivities. 

(2) The films had to have acceptably low 

temperature coefficients. 

(3) The ruthenium had to be used as 

economically as possible. 

Conduction through Ruthenium 

Dioxide 

Ruthenium dioxide is a black, electrically 

conducting crystalline solid with the rutile 

structure. Unlike palladium oxide, it can be 

heated in air to 110o”c without physical or 

chemical change, and is almost completely 

insoluble in a wide variety of frit and glass 

compositions. 

It can seldom, if ever, be prepared as 

stoichiometric RuO,, and is usually partially 

defective in oxygen, with a corresponding 

amount of Ru3+ in place of Ru4+ in the crystal 

lattice. Valency control within narrow limits 

was obviously necessary if stable resistors 

based on ruthenium dioxide were to be 

developed. 

Work on the control of deviating valencies 

in semiconducting oxides, in particular 

nickel oxide, was reported by E. J. W. Verwey 

Platinum Metals Rev., 1967, 11, (4) 127 

and his co-workers at Philips in 1950 (I). It 

was shown that introduction of suitable ions 

into the lattice structure of a variable oxide 

could, without deforming it, balance the ions 

of deviating valency already within the lattice 

and still maintain overall neutrality. For 

example, Verwey obtained a composition 

Li8+Ni2+(l-,8) Nia3-0 by calcining lithium 

carbonate with nickel oxide at IZOOT under 

oxidising conditions, The product had the 

same structure as nickel oxide, but with a 

smaller unit cell, and the Ni3+ content was 

broadly equivalent to the amount of lithium 

oxide added. 

This suggested that valency variations in 

ruthenium dioxide might be controlled by a 

similar “doping” technique, leading to a 

better reproducibility from batch to batch, 

together with a measure of control over both 

resistivity and temperature coefficient. 

Control of Valency 

The oxides of Group Va metals were 

selected for investigation. Pentavalent ions 

would be necessary to balance the Ru3+ ions 

in the lattice and maintain overall neutrality, 

and M5+ ions of Group Va metals have a 

radius within &IS per cent of that of the 

RLP ion, which is about the limit for the 

entry of an ion of one species into the lattice 

of another in significant quantity. It was 

found that niobium pentoxide could be

introduced into the ruthenium dioxide lattice 

in quantities up to 50 per cent molecular, and 

that the results obeyed Vegard's Law, which 

states in effect that the extent of the change 

in lattice parameter of the host oxide is 

proportional to the molecular percentage of 

added dopant. This linearity provides a 

useful means of monitoring the composition 

by X-ray diffraction before processing into 

a resistor preparation. 

Moreover, since the temperature coefficient 

of resistance of ruthenium dioxide is metallic 

in nature and strongly positive, introduction 

of a non-conducting oxide might be expected 

to exert a negative influence on the tem- 

perature coefficient. Thus control of tem- 

perature coefficient in addition to resistivity 

might be achieved. 

Further work showed that resistance values 

were largely governed by the ratio of doped 

ruthenium dioxide to glass, and temperature 

coefficients by this ratio in conjunction with 

the molecular percentage of niobium pent- 

oxide in the ruthenium dioxide lattice. For 

example, ruthenium dioxide glaze films in a 

wide range of resistance values were found to 

have positive coefficients in excess of 1000 x 

10 "OC. As the molecular percentage of 

niobium pentoxide in the calcine was in- 

creased the temperature coefficient decreased, 

positive influence of the silver being compen- 

sated by the negative influence of the niobium 

pentoxide on the temperature coefficient. 

Thus silver provided an additional means of 

controlling temperature coefficient in addition 

to reducing the cost of the resistor preparation. 

The Glaze Component 

Investigation of the glaze component of the 

resistor compositions showed that this had a 

significant effect on some electrical properties. 

Glasses of the lead borosilicate type promoted 

high positive temperature coefficients, often 

exceeding 500 x IO-~/"C and 2000 x IO+/"C 

respectively with doped and undoped ruthenium 

dioxide. Better results were obtained 

with zinc and cadmium borosilicate glasses. 

Electrical Properties 

At present four basic ruthenium oxide 

preparations are available commercially (2), 

covering the range from 100 to 3000 ohms/ 

sq./mil., but it is expected that seven preparations 

will ultimately be produced, firing 

at 600°C upwards, to cover the range 5 to 

IOO,OOO ohms/sq. /mil. Intermediate values 

may of course be obtained by blending the two 

standard compositions nearest to the desired 

resistance. 

Little difficulty should be experienced in 

reaching a negative value of IOO x IO-~//"C controlling values to within &zo per cent 

with 20 per cent molecular content of of nominal, with the possibility of maintaining 

niobium pentoxide. 

better than AIO per cent with good machines 

Since the niobium and ruthenium oxides under closely controlled conditions. 

are reacted by calcination before incorpora- Temperature coefficients in the range ~ 100 

tion in the resistor preparation, no reaction to f ~oo x IO-~/"C can be expected with sheet 

occurs when the preparation is subsequently resistivities from 50 to 1000 ohms/sq./mil. As 

fired on the substrate, and electrical properties resistivity increases the temperature coeffiwere 

not unduly affected by variations in the cient tends to become more negative, and 

time of firing or in the temperature and values of +50 to -250 can be expected with 

atmosphere in the furnace, 

resistivities from 1000 to 10,000 ohms/sq./mil. 

Silver powder was found to be a useful For even higher resistivities temperature 

addition to ruthenium dioxide based pre- coefficients between -zoo and -500 may be 

parations. Up to 60 per cent of the ruthenium expected at present, but this may be reduced 

dioxide could be replaced with silver without later to o to -300 x IO-~/"C. 

adversely affecting the temperature coefficient Ruthenium dioxide glaze resistor films 

provided a balance was struck between the subjected to a load of gW/in.2/mil. at 70°C 

niobium pentoxide and silver contents, the for 1000 hours showed a drift in resistance 

Platinum Metals Rev., 1967, 11, (4) 128

value of

The Platinum Metals in Fuel Cells 

SECOND INTERNATIONAL CONFERENCE IN BRUSSELS 

The merits of the platinum metals as electrocatalysts in a large number of 

fuel cell systems featured in a high proportion of the papers presented at 

the Second International Conference on the Study of Fuel Cells, organised 

by the Soci6t6 #Etudes de Recherches et d’Applications pour l’lndustrie 

(SERAI) and the SociBtB Commerciale d’Applications Scientijques 

(COMASCI) and held recently at the University of Brussels. 

More than fifty papers were presented at 

this meeting on all aspects of fuel cell 

technology, ranging from considerations of 

theoretical models of the processes taking 

place at working electrodes to outlines of the 

basic economics of the manufacture and use of 

fuel cells. Several instances of working cells 

producing power in the I to z kW region were 

described. 

The superiority of platinum as an electro- 

catalyst has been clearly demonstrated by 

numerous researches, particularly in those 

fuel cells designed to work at ambient 

temperatures or in corrosive electrolytes, but 

the view has frequently been expressed that 

its high cost is a disadvantage for use in large 

scale commercial applications. C. G. Clow 

of Energy Conversion, presenting the results 

of an analysis of the basic economics of 

various types of low temperature fuel cells 

using alkaline electrolytes, pointed out that 

the cost of electricity generation comprises 

capital costs, maintenance and fuel, and that 

the use of the cheapest fuel and high efficiency 

did not necessarily mean the most economic 

generation of power. The cost of materials 

and fabrication of the fuel cell unit depend on 

the fuels and conditions used, and in certain 

systems the cost of electrodes with platinum 

loadings of less than 3 mg.cm-2 did not 

constitute the major item of expense. 

A new type of gas diffusion electrode was 

described by R. G. Haldeman and his co- 

workers of the American Cyanamid Company. 

This is made by impregnating a conductive 

graphitic carbon, bonded with fibrous poly- 


tetrafluoroethylene, with chlorplatinic acid 

in ethanol and reducing at 225%. The 

novelty of this electrode is that a high degree 

of structural cohesion and flexibility is 

obtained even with very high proportions of 

the conductive graphite. Excellent results 

were obtained for reactions of hydrogen and 

oxygen in both acid and alkaline media at 

low platinum concentrations. 

Fuel cells having particular applications in 

view were described by M. I. Gillibrand and 

J. Gray of Electrical Power Storage, and by 

C. G. Telschow and co-workers at Brown 

Boveri. In the former case capacities of over 

10,000 ampere-hours without attention were 

claimed from cells operating at low current 

densities with compressed hydrogen and 

oxygen; such cells are ideal for use as power 

sources in navigational buoys and unattended 

beacons. In a buoy a life of three years 

between servicing would be possible, and a 

shore-based beacon could operate for six 

months without attention. Similarly the 

Brown Boveri equipment had an expected six 

months unattended life, and could therefore 

be used in certain areas of the world in 

telephone and television relay stations. This 

cell utilises a platinum metal catalyst for the 

direct oxidation of methanol in an alkaline 

electrolyte and is capable of producing power 

at temperatures down to - 10°C. 

Both acid and alkaline electrolytes can be 

used in direct methanol oxidation systems, as 

was pointed out by H. H. von Dohrcn and his 

colleagues at Varta. Both electrolytes have 

their advantages and Varta currently use

potassium hydroxide solutions in their experi- 

ments. Measurements made by this group 

indicated that below 80°C non-precious 

metals did not work very well, while of the 

platinum group metals platinum, palladium, 

palladium-platinum alloys and platinum- 

rhodium alloys were the most active at 

ambient temperatures. 

The study of alloys of the platinum group 

metals for fuel cell applications continues to 

attract interest. Thus J. H. Fishman of 

Leesona Moos Laboratories had investigated 

the use of palladium-gold alloys for oxygcn 

reduction in alkaline media. When a foil was 

used, a maximum in the activity versus com- 

position plot was obtained with alloys con- 

taining 35 to 40 atomic per cent gold, and a 

sharp decrease in activity was observed in 

alloys containing greater than 80 atomic per 

cent gold. Similar behaviour was found when 

finely divided alloy powders were used, the 

activity maximum now occuring at 50 atomic 

per cent gold, sharply declining at 60 atomic 

per cent gold, irrespective of the method of 

preparation of the alloy. 

J. Bersier of Siemens has investigated the 

diffusion of hydrogen through silver- 

palladium alloys, since the use of such alloys 

in the construction of non-porous diffusion 

electrodes avoids the difficulties arising from 

the brittleness and cracking experienced with 

pure palladium. Measurements of the 

diffusion coefficient of hydrogen as a function 

of hydrogen concentration and temperature in 

the range 30 to 3oocC show that it is largely 

governed by the concentration of occluded 

hydrogen, and that for the 23 per cent silver- 

palladium alloy a definite minimum occurs in 

the concentration range 0.1 to 0.2 H/Me not 

explicable by the existence of a two-phase 

zone in the alloy. 

D. E. W. 

Further Expansion in Platinum Production 

A NEW REFINERY IN SOUTH AFRICA 

Although a furthcr incrcase in the 

output of platinum to 750,000 ounces 

a year was announced by Rustenburg 

Platinum Mines as recently as October 

of last year, yet another step in the 

expansion programme has been de- 

cided upon. Plans to increase mining 

capacity to an annual equivalent of 

about 850,000 ounces of platinum - 

with corresponding amounts of the 

other platinum metals - have been put 

in hand and are expected to begin 

yielding thcse additional amounts of 

metal by the end of 1969. The capital 

expenditure involved in the complete 

expansion programme over the years 

1967 to 1971 will exceed 815 million. 

Extensions to the smelting and refining facilities are also in hand both at Matte Smelters 

(jointly owned by Rustenburg and Johnson Matthey) and at the Johnson Matthey plants 

in the United Kingdom. 

In addition, Johnson Matthey have decided, subject to the necessary Government 

authority being granted, to build a platinum refinery as an extension to the opcrations 

already carried out at Wadeville by Johnson Matthey & Co South Africa (Pty) Limited. 

This new refinery will be constructed and equipped during 1968 and will come into 

operation in the early part of 1969. It will take partially refined material treated by 

Matte Smelters at Rustenburg and produce pure platinum, palladium, rhodium, iridium, 

ruthenium and osmium as well as their compounds. The new Johnson Matthey refinery at 

Wadeville will complete the plans for handling Rustenburg’s increased output and will, 

for the first time, make platinum metals available in marketable forms in South Africa. 


The Platinum-Molvb denurn System 

J J 

THE FORMATION OF INTERMEDIATE PHASES 

By G. L. Selman, BS~. 


Although platinum-clad molybdenum is used extensively as a material for 

handling molten glass, surprisingly little is known about the constitutional 

relationships in this refractory metal binary system. Recent work in the 

Johnson Matthey Research Laboratories has conjrmed that the pub- 

lished equilibrium diagram is incomplete and that four intermediate 

phases are formed at high temperatures. This work has provided a better 

understanding of the behaviour of platinum-clad molybdenum equipment 

under operating conditions in the glass industry. 

Advances in glass technology, leading in 

many instances to increased handling temper- 

atures, are placing an ever-increasing burden 

upon glass handling equipment. Emphasis is 

being placed more and more on the use of 

composite materials, such as molybdenum 

with an outer cladding of platinum, which 

take advantage of both the excellent high 

temperature mechanical properties of the 

refractory metals and the outstanding oxi- 

dation resistance and general chemical in- 

ertness of the platinum metals. 

While the stirrers, mandrels and electrodes 

constructed of platinum-clad molybdenum 

have useful lives at temperatures of up to 

12oocC, at higher temperatures, although this 

combination represents the most economic 

and technically satisfactory choice, inter- 

reaction between the two metals takes place, 

so that the life of the platinum sheath is 

largely dictated by the rate at which molyb- 

denum diffuses through it and by the effect 

of the intermediate alloy layers so formed 

upon its integrity. 

It is therefore becoming increasingly im- 

portant to the metallurgist concerned with 

this problem that he has at his command 

sound information concerning the binary 

alloys of the platinum metals with the 

refractory metals at temperatures up to 


15ooOC. Such information is not generally 

available in the literature. 

During the course of recent diffusion 

studies made in these laboratories on 

molybdenum rods mechanically clad with 

platinum sheaths, metallographic evidence 

confirming the existence of four intermediate 

alloy phases in this complex binary system has 

been obtained. The solubility of platinum in 

molybdenum in the temperature range 1400' 

to 170oCC has also been determined by direct 

analysis of the microstructure of two molybdenum-rich 

alloys made by conventional 

alloying techniques. The solubility has been 

found to increase rapidly with temperature 

in this region. The results of this investigation 

bear interesting comparison with the 

previous studies made on this system. 

Previous Constitutional Work 

The earliest reference to the platinum- 

molybdenum system appears to be that due to 

Dreibholz (I) who suggested that about 16 

weight per cent molybdenum should be 

soluble in platinum at the eutectic temper- 

ature, this figure decreasing to less than two 

per cent at room temperature. Hultgren and 

Jaffee (2) studied electron beam melted alloys 

containing up to 50 atomic per cent molybdenum 

after annealing at IOOO"C. The X-ray

Fig. 1 Tentative constitutional 

diagram of the molybdenumplatinum 

system as proposed 

by Knapton (6). The present 260C 

studies have confirmed that two 

ndditional intermediate phases 

exist, and have also shown that 

the solubility of platinum in 

molybdenum is considerably 220c 

higher than the diagram would 

suggest at temperatures above 

1400°C 

U 

w I800 

a 

2) 

b 

4 

u1 Z' 

n 

3 I- 

1400 

1000 

600 

patterns that were obtained showed a single 

face centred cubic phase, with lattice con- 

stants near to that of platinum, for all 

compositions. 

The first systematic investigation was 

carried out by Raub (3) who studied arc 

melted alloys. He observed very little 

solubility of platinum in molybdenum but 

found that molybdenum was appreciably 

soluble in platinum. He detected a tetragonal 

distortion of the face centred cubic lattice in 

platinum-rich alloys containing more than 

about 25 atomic per cent (14 weight per cent) 

of molybdenum to give an axial ratio greater 

than 1.0. This new phase, denoted al, 

separated from the terminal solid solution 

below 14oo0C. A hexagonal close packed E 

phase was found to form at about Pt3M02, 

with a very wide composition range. Further 

references to this hexagonal phase were made 

by Greenfield and Beck (4) and Nishimura 

(5). The latter author constructed an 

equilibrium diagram on the basis of melting 

LIQUID Mo +\ 


b 

Mo+E 

b b 

I 

2 r 

ATOMIC PER CENT PLP 

KNAPTON RAUB 

0 0 Pt 

A A eta, 

v V E+Pt 

+ 0 E 

b D € 

B n aI 

X MELTING POINTS 

*oa 00 

.. \+a; 

0 

NUM 

a 

OD 0 

-x-4 

80 I 

point determinations, X-ray analyses and 

microscopical examinations. Platinum-rich 

alloys were shown to form via a peritectic 

reaction, 

Liquid f p z ci 

and molybdenum rich alloys formed via a 

eutectic 

Liquid 2 p + y (Mo). 

Nishimura ascribed the composition PtMo to 

the hexagonal phase, and his diagram 

suggests an appreciable solubility of platinum 

in molybdenum at the eutectic temperature. 

Nishimura did not account for the tetra- 

gonal phase in his work, and the constitutional 

diagram representing the best combination of 

evidence available at that time is that due to 

Knapton (6), reproduced in Fig. I. It is 

obvious that no attempt has been made to 

determine the phase boundary positions 

accurately, and this diagram can only be 

regarded as tentative. 

The first suggestion that the diagram was 

incomplete came from Kirner (7) who claimed

to have observed a new phase, stable only at 

high temperatures, at the molybdenum-rich 

end. 

Figure I illustrates the lack of previous 

experimental work in this region, and it is not 

too surprising that such a phase remained 

undetected. Thc phase was very hard, and 

readily observable in both arc melted alloys 

and diffusion couples heat treated at 1400' and 

ISOOT. It decomposed on heating for 30 

hours at 1200°C. 

Rooksby and Lewis (8) conducted the most 

recent study of this system. During their 

experiments they heated fine platinum-clad 

molybdenum wires under controlled conditions 

which produced the intermediate phases 

in turn on the coating surface, from which 

X-ray diffraction patterns were then obtained. 

The compositions of the phases so formed 

were not determined directly, but were 

approximately fixcd by analogy with other 

isostructural compounds from the X-ray diffraction 

data. 

Table I, which is reproduced in part from 

Rooksby's paper, lists the phases identified 

and some typical heat treatments which were 

required to produce them at the coating 

surface. 

Table II 

Table I 

Electron Probe Microanalyses of 

Intermediate Phases in the 

Platinum-Molybdenum 

the Four Intermediate Phases 

System 

Phase Mo Structure Heat rt Treatment 

/I (Pt,Mo) Wt.yo Tetragonal At.?, Wt.:/, rooo"C At.o/b for 

(a, Raub) 24 hr 

y (Pt,Mo) I 67.5 81.0 

Orthorhombic 

31.5 

r~oo"C 

18.5 

for 

I1 24 hr 

6 (Pt,Mo,) 

34.0-45.0 

H.C.P. 

51.1-62.5 54.4-65.0 

13ooOC 

37.0-47.8 

for 

(E Raub) I 

I11 

hr 

P (PtMo,) 

26.5 

Cubic 

42.6 

A15 

75.0 

13oo0C 

59.6 for 

24 hr 

IV 28.5-24 31.6-39 77.0-81.3 62.2-67.6 

Rooksby and Lewis thus identified two 

phases in addition to those originally pro- 

posed by Raub, the orthorhombic y and the 

$-tungsten structure designated E. Both of 

these phases had very narrow composition 

ranges, judging from the small variations 

observed in their lattice spacings. The 

molybdenum-rich phase due to Kirner is thus 


in all probability PtMo,, isostructural with the 

P-tungsten phase previously observed in 

iridium-molybdenum alloys (9). 

Experimental Diffusion Studies at 

High Temperatures 

Platinum-molybdenum diffusion couples have 

been examined extensively in these laboratories 

in recent times as part of a general 

investigation into the uses of platinum at high 

temperatures. Pressure bonded sheets have 

been found to be unsuitable for long term 

annealing above 1300"C, due to a tendency for 

the components to peel apart, and the test 

specimens which formed the basis for the 

major part of this work were manufactured 

from spectrographically pure Murex molyb- 

denum rod and high temperature grade 

platinum tubing of 0.060 inch wall thickness, 

containing typically about 0.0075 per cent 

total impurity. 

Short lengths of the molybdenum rod were 

vacuum sealed into the close fitting platinum 

tubes, and the two mctals were then bonded 

by lightly hot swaging the assemblies at 

1200°C. The annealing tests were conducted 

in air at 1400°C. The specimens were freely 

supported in the hot zone of a mullite tube 

furnace at this temperature for periods up to 

2000 hours, following which they were cooled 

in air and sectioned for metallographic 

examination. These composite specimens 

were difficult to etch chemically because of the 

vastly differing response of the two metals to 

the etching solution. The microstructures 

were revealed most clearly by cathodically 

etching the polished sections in a stream of 

low pressure argon. 

Microstructure and Constitution of 

the Diffusion Zones 

Diffusion couples prepared in the manner 

described in the foregoing section maintained 

their integrity throughout the annealing 

cycle, and no interfacial failures occurred. 

Fig. 2 shows the diffusion zone formed in a 

platinum-clad molybdenum specimen by 

annealing for 1100 hours at 14ooOC. The

Fzg. 2 A molybaknum-platinum interlace after 

annealing for 1100 hours at 1400"C, showing the 

four intermediate alloy layers formed during the 

heat treatment. x 200 

1600 

11400 

I 

t1200 

- 1000 

HV 

- 

- 800 

I 

t 6oo 

I 200 

00 

eo c 

z 

60 u" 

[L 

w 

1500 

P 

4o t- 

I 

!? 

20 g 

0 I00 200 300 

Fig. 3 A microhardness scan made across the inter- 

face shown in Fig. 1. The hardness levels can be 

readily identtfied with the mirrostruetiire 

0 - 

TRAVERSED LENGTH (MICRONS) 

Fig. 4 Electron probe scans for molybdenum and 

platinum across the interface shown in Fig. 1. The 

intermediate alloy layers are well dejined and can 

be accurately related to hardness and microstructure 


1 

intimately convoluted nature of the inter- 

mediate alloy layers, which makes it difficult 

to isolate and follow the somewhat erratic 

formation of the phase adjacent to the 

molybdenum, was a noteworthy and fairly 

typical feature of the microstructures ob- 

served during the course of this work. 

Rooksby and Lewis showed from their X-ray 

data that the structural transitions from one 

phase to the next occur with the minimum of 

atomic movement and alteration of lattice 

spacings, in spite of considerable changes in 

composition. This close relationship between 

the phases, which resemble a series of dis- 

crete but ordered solid solutions, could well 

account for their somewhat intimate associa- 

tion within the microstructure. 

On close scrutiny it was possible to resolve 

four intermediate phases in the diffusion zone, 

in complete agreement with the findings of 

Rooksby. These phases are defined more 

clearly in the microhardness and microprobe 

traverses made across the diffusion zone, 

shown in Figs 3 and 4. 

The curve of microhardness across the 

diffusion zone is remarkably similar in shape 

to those obtained by Kirner, who studied 

diffusion couples annealed at 1400' and 

1500°C. This worker suggested that the peak 

at the molybdenum-rich end of the traverse 

was due to his new phase, and identified the 

second peak with the hexagonal phase dis- 

covered by Raub. Comparison of the micro- 

hardness curve with the microprobe scan 

strongly suggests, however, that the hexagonal 

6 phase is more closely related to the mini- 

mum between the two peaks, and that the 

second peak occurs within the orthorhombic 

y phase discovered by Rooksby. 

The microprobe traverse confirms Raub's 

finding that the terminal solubility of platinum 

in molybdenum is small at intermediate 

temperatures, and highlights the extensive 

composition range of the hexagonal phase. 

In an attempt to establish the compositions 

of the intermediate alloy layers with some 

accuracy, point analyses were made at 20 kV 

on each of the four phases shown in the

Fig. 5 The substantially single 

phase microstructure of a 20 

per c e platinum-molybdenum 

~ 

alloy quenched after annealing 

for 7 hours at 1850°C. x 200 

Fig. 6 The 20 per cent Fig. 7 The pearlitic structure 

platinum-molybdenum alloy formed by anneuling the 20 

quenched after annealing for per cent platinum-molybdenum 

7 hours at 170O"C, showing the al1o.y for 165 hours at 1250°C. 

typical high temperature x 750 

duplex microstructure. x 200 

diffusion zone. The radiations used were to the compositions PtMo3, PtMo, Pt,Mo, 

PtLa and MoLa. After correction for atomic and Pt,Mo, a sequence which is not well 

number and absorption effects the values supported by any of the previous investi- 

given in Table I1 were obtained. gations. 

Wt.yo At.?, Wt.:/, At.o/b 

The Solubility of Platinum 

in Molybdenum 

The form of the molybdenum-rich end of 

the binary system envisaged by Knapton 

(Fig. I) appeared from our own results, and 

I 67.5 81.0 31.5 18.5 

from those of Kirner and Rooksby, to be 

seriously in error. 

Alloys containing 10 and 20 weight per cent 

I11 26.5 42.6 75.0 59.6 

IV 28.5-24 31.6-39 77.0-81.3 62.2-67.6 

The analyses are quoted to an estimated 

accuracy of & 3 per cent. The composition 

ranges obtained for phases I1 and IV at 

1400°C agree remarkably well with those 

shown on the tentative diagram due to 

Knapton (Fig, I) for the hexagonal (E) and 

tetragonal (q) intermediate phases. 

Taken in order, however, they bear little 

resemblance to the sequence of structures 

reported by Rooksby, with the possible 

exception of phase I. Taken in isolation, the 

analytical results suggest that the atomic 

arrangements of the four phases correspond 

Platinum Metals Rev., 1967, 11, (4) 

1111 26.5 42.6 75.0 59.6 

IV 28.5-24 31.6-39 77.0-81.3 62.2-67.6 

136 

platinum were prepared, from starting 

materials of similar purity to those used for 

the diffusion studies, in an argon arc furnace. 

The melted buttons were turned and remelted 

several times, and finally heat treated for 

seven hours at 1850°C to ensure homo- 

geneity. Samples from each ingot were then 

annealed at temperatures ranging from I IOO 

to 185o"C in an argon atmosphere for long 

periods, quenched and prepared for metallo- 

graphic examination. 

Figs 5, 6 and 7 show microstructures 

typical of the 20 per cent alloy quenched from 

185o"C, 1700OC and 125oOC. Although some 

grain boundary precipitation has occurred in 

the sample quenched from 1850°C it would 

seem that the alloy was substantially a single

Fig. 8 Boundary curves for the molybdenum-rich 

terminal soEid sobtion and the high temperature E 

phase as determined by electron probe microanalysis 

of alloys in the duplex region 

phase solid solution at the soaking temperature. 

Untreated filings taken from this 

specimen gave a diffraction pattern corresponding 

to a body centred cubic structure 

with a lattice parameter a == 3.143& a value 

slightly lower than that of pure molybdenum. 

At lower temperatures a second phase 

separated from this terminal solid solution 

(Fig. 6) which in turn decomposed at temperatures 

below about 1300OC to yield the pearlitic 

microstructure shown in Fig. 7. X-ray diffraction 

showed that the high temperature duplex 

microstructure was composed of body centred 

cubic and cubic @-tungsten) structures, the 

latter corresponding to the E phase described 

by Rooksby. The low temperature duplex 

structure consisted of a body centred cubic 

and a hexagonal phase corresponding to that 

designated by Rooksby as 6. 

The individual phases present in specimens 

quenched from temperatures above 1300'C 

were fully resolvable under the electron 

probe microanalyser, and their compositions 

were determined. The analytical results have 

been plotted in Fig. 8, which illustrates the 

very rapid increase in the solubility of platinum 

in molybdenum between 1400' and 

17oo0C, and the constancy of the high temperature 

E phase composition over this region. 

The E phase decomposes eutectoidally at 

1325' iz j"C, according to the metallographic 

evidence obtained on the two alloys examined. 

Practical Significance of the High 

Temperature Phase Relationships 

When attempts are made to use the desirable 

properties of platinum-clad molybdenum at 

temperatures above 1300T failure tends to 

take place in a characteristic manner. Large 

distortions of the sheath begin to occur, 

giving the component a "blistered" appear- 

ance, and eventually the sheath cracks, so that 


l800, I t 

1200 

(Mo) i-& 

0 10 20 

ATOMIC PER CENT PLATINUM 

catastrophic oxidation of the molybdenum can 

take place without hindrance. Such failures 

are rarely associated with the complete 

diffusion of molybdenum to the outer 

platinum surface. 

From laboratory experience with the manu- 

facture of test composites it has become quite 

clear that unless special precautions are taken 

it is difficult to maintain a coherent interface 

during annealing when the heat treatments are 

carried out above 1300°C, and that this 

difficulty is mainly due to high interface 

strains associated with the formation of the 

high temperature intermetallics in the difi- 

sion zone. The formation of these phases 

could similarly account for the distortions ob- 

served in glass handling equipment used at 

high temperatures. 

Further theoretical work on this and other 

refractory metal platinum systems which are 

potentially useful at high temperatures would 

thus be of considerable practical value to 

metallurgists and engineers concerned with 

plant design and development. 

References 

I L. Dreibholz, Z. phys. Chem., 1924, 108, 5 

2 R. Hultgren and R. I. Jaffee, J. Appl. Phys., 

1941, 12, 501 

3 E. Raub, Z. Metallk., 1954, 45, 23 

4 P. Greenfield and P. A. Beck, Trans. A. I.M.E., 

1956,206, 265 

5 H. Nishimura, Nippon Kinzoku Gakkai-Si, 

1958, 22,425 

6 A. G, Knapton, Planseeber., 1959, 7, 2 

7 K. Kirner, Metall, 1962, 16, (7), 672 

8 H. P. Rooksby and B. Lewis,J. Less-Common 

Metals, 1964, 6, 451 

9 A. G. Knapton, 3. Inst. Metals, 1958-59,87,28

Electron Configuration and Crystal 

Structure of Platinum Metal Alloys 

INTERMEDWTE PHASE FORMATION INTERPRETED 

IN TERMS OF THE ENGEL-BREWER CORRELATION 

By A. s. Darling, Ph.D., A.M.1.Mech.E. 


The platinum metals react with some 

of their closer neighbours in the Periodic 

Table to produce intermediate phases of 

high stability. While this behaviour 

tends to conjrm some of the predictions 

made by protagonists of the Engel- 

Brewer theory of alloying, the general 

validity of this theory is still a matter of 

vigorous controversy. In this article 

some of the conflicting opinions that 

have been advanced are reviewed and 

discussed. 

Correlations between the electron con- 

figuration and crystal structures of the 

metallic elements and their alloys were first 

proposed by Engel in 1949 (I, 2), and since 

that time Brewer has enlarged and refined the 

original conception and has used it to predict 

constitutional relationships in a wide range 

of alloys (3, 4, 5). Recent comments by 

Hume-Rothery (6, 7) have stimulated a great 

deal of discussion; the Engel-Brewer theory 

has been brought to the attention of a wide 

range of metallurgical opinion and is no 

longer a matter of purely academic interest. 

The basic point of contention is whether a 

hypothesis, suggested originally by the 

valency and crystal structure sequence ex- 

hibited by sodium, magnesium and alumin- 

ium, can with justification be used to inter- 

pret the behaviour of the transition metals 

and their alloys. Since the elements to the 

right of ruthenium and osmium in the second 


and third long periods do not use all their 

valency electrons for bonding, differing inter- 

pretations of their alloying behaviour have 

figured prominently in the papers referred to 

above. Before exploring the implications of 

the theory so far as the platinum metals are 

concerned, its general background and scope 

deserve a little attention. 

Genesis of the Theory 

The integral electron concentration theory 

first advanced by Engel was in fact an exten- 

sion and generalisation of some of Hume- 

Rothery’s ideas on electron compounds (8,g). 

When considering intermediate phases con- 

taining iron, cobalt or nickel, Hume-Rothery 

was able to correlate crystal structure and 

electron atom ratios only by assuming that the 

transition element contributed no electrons 

to the crystal structure. Engel, however, 

concluded that the d electrons of the transition 

element participated in the bonding of these 

intermediate phases, thus explaining their 

high melting points. The Engel-Brewer 

theory now states that all unpaired electrons 

participate in crystal bonding, but that the 

d electrons have no effect upon the type of 

crystal symmetry adopted, which is deter- 

mined solely by the number of s and p 

electrons. 

Thus the I, z and 3 valency electrons of 

sodium, magnesium and aluminium explain 

why these elements crystallise respectively 

in the b.c.c., h.c.p. and f.c.c. systems of 

symmetry. The b.c.c. lattice is apparently 

stable from I to 1.75 electrons/atom, the

h.c.p. lattice from 1.8 to 2.2, while the f.c.c. 

lattice extends from 2.25 to more than three 

electrons per atom (10). 

To thermodynamic aspects of the Engel- 

Brewer correlation Professor Hume-Rothery 

has so far devoted little attention. This part 

of the theory is of great interest as it provides 

a strong link between the electronic approach 

and metallurgical thermo-chemistry. When 

for example the e1ectron;atom concentration 

suggests hexagonal and body centred struc- 

tures of comparable total energy, the theory 

predicts that the b.c.c. structure will be the 

stable high temperature form, as the h.c.p. 

structure, having a lower co-ordination would 

make a larger contribution to the high tem- 

perature entropy. 

Transition Metal Compounds 

The theory indicates that combinations of 

the transition elements from the left and right 

of the Periodic Table should produce com- 

pounds of high stability. Metals from Rb to 

Tc and Cs to Re use all their valency electrons 

for bonding while the platinum metals do not. 

A mixture of these two types of atom pro- 

motes, therefore, a flow of electrons from the 

element with an excess to that with vacant 

orbitals. Thus when Zr and Ir are alloyed 

the Ir donates electrons to the Zr. The 

stability of the compound Zr Ir, thus formed 

is according to Brewer (5) attributable to the 

fact that 31 electrons contribute to the 

bonding process compared to the 25 bonding 

electrons of the uncombined atoms. 

For a given base metal the number of 

electrons transferred on combination should 

increase as the atomic weight of the platinum 

metal increases. This explains, in a qualitative 

way, the high stability of Zr Pt, compared to 

Zr Ir,. Brewer has attempted (5) to verify 

the prediction in a more specific manner by 

heating zirconium carbide with Pt, Ir and 0s. 

In all instances the carbide dissociated, 

graphite was liberated and the zirconium 

formed an intermetallic compound with the 

platinum metal. 

These platinum metal compounds must 


therefore be more stable than zircomum 

carbide. Experiments of this sort reported 

by Raub (I I) several years ago used in general 

lower concentrations of carbide, and in most 

instances the base metal was taken into solid 

solution by platinum. 

Zirconium carbide, although one of the 

most stable known, has a lower free energy 

of formation than the refractory oxides. 

Bronger and Klemm (12) showed in 1962 that 

zirconium oxide can be effectively reduced by 

hydrogen in the presence of platinum, and 

this has been cited by Brewer in support of 

his general predictions. Aluminium oxide was 

also reduced however, and the solubility of 

aluminium in platinum is high. The activity 

of aluminium in this dilute solid solution must 

therefore have been very low. 

Bronger also reported the reduction of 

yttrium and lanthanum oxides with hydrogen 

in the presence of platinum with the forma- 

tion of the compounds Pt, Y and Pt, La. All 

the lanthanides between lanthanum and 

thulium have since (13) been reduced in a 

similar manner. In this series of experiments 

dry ammonia was employed as a reductant. 

Complete reductions were achieved at 1200°C 

for all elements with the exception of samar- 

ium and europium which required tempera- 

tures between I350 and 1500°C. 

Some Inconsistencies 

It is reported (14) that hafnium and plati- 

num, when heated together, react with ex- 

plosive violence. This finding, and the other 

results reported above, leave no doubt that 

the compounds between platinum and those 

base metal transition elements which form 

refractory oxides are of quite extraordinary 

stability. 

For practising metallurgists, howcver, many 

baffling inconsistencies remain. Platinum and 

palladium can, for example, be safely melted 

under hydrogen in zirconia crucibles. Slight 

contamination of the platinum metal undoubt- 

edly occurs under such conditions, although 

it is a minor effect and usually associated with 

silicious attack. Refractory oxide dispersants

in a solid platinum matrix are, however, 

notoriously unstable, and this appears to 

suggest a high affinity of solid platinum for the 

refractory metal. 

Differences in geometry could also be in- 

volved in these apparent anomalies as plati- 

num, when held molten against a refractory 

wall, might prevent complete removal of 

gaseous reaction products such as water 

vapour. 

The experimental results and interpreta- 

tions given in this recent group of papers 

will undoubtedly lead to a great deal of 

further work, and should moreover encourage 

detailed constitutional studies on platinum 

metal alloys. 

References 

I N, Engel, Metals as Electron Concentration 

Phases, Kern. Maanedsbl, 1949, 30, 53 

Brazing Graphite to Metals 

A NEW PALLADIUM-BASE BRAZING ALLOY 

FOR NUCLEAR ENERGY APPLICATIONS 

The development of advanced molten-salt 

reactors posed a problem of making mechanic- 

ally strong and pressure-tight joints between 

graphite and refractory metals and alloys for 

service in contact with fused fluorides at 

elevated temperatures. According to a report 

recently released from Oak Ridge National 

Laboratory (USAEC Report ORNL-3970, 

1966), a satisfactory solution to this problem 

was found in brazing with a new palladium- 

base brazing alloy. 

The new material, melting below IZSO”C, 

is based on the well-known 60 per cent 

Pd-40 per cent Ni brazing alloy to which 

5 per cent chromium was added at the expense 

of nickel. Palladium was chosen as the basis 

of the new alloy because of its relatively low 

thermal neutron cross section (eight barns) 

and its good resistance to the corrosive action 

of molten salts; chromium, which is one of the 

carbide forming elements, was added to make 

the alloy capable of wetting graphite. 

As was to be expected, the 60 Pd-35Ni-5 

Cr alloy exhibited good wetting properties on 

graphite, molybdenum and tungsten. Lap 

joints made with this alloy between graphite 

and molybdenum parts in a vacuum furnace 

at 1z5o”C were defect-free not only in the 


2 N. Engel, Alloys as Electron Concentration 

Phases, Ibid., 97, 105, 113 

3 L. Brewer, Paper in “Electronic Structure and 

Alloy Chemistry of the Transition Elements”, 

Ed. I?. A. Beck, Interscience New York, 1963 

4 L. Brewer, “Predictions of High Temperature 

Phase Diagrams”. UCRL 10701, Univ. Cali- 

fornia, 1963 

5 L. Brewer, Acta Metall., 1967, 15, 553 

6 W. Hume-Rothery, Ibid., 1965, 13, I039 

7 W. Hume-Rothery, Ibid., 1967, 15, 567 

8 W. Hurne-Rothery “The Structure of Metals 

and Alloys”. Monograph and Report Series 

No. I, Inst. Metals, London, 1936 

g W. Hume-Rothery, “Atomic Theory for 

Students of Metallurgy”. Monograph and 

Report Series No. 3, Inst. of Metals, London, 

I948 

10 N. Engel, Acta Metall., 1967, 15, 565 

11 E. Raub and G. Falkcnburg Z. Metallkunde, 

1964,559 186 

12 W. Bronger and W. Klemm, Z. anorg. allgem. 

Chem., 1962, 319, 58 

t3 W. Bronger, J. less-common Metals, 1967, 12, 

63 

14 J. Margrove, note to (5) 

as-brazed condition but also after thermal 

cycling tests (ten cycles between 700°C and 

room temperature). A 1000 hours test in a 

molten LiF-Be,F,-ZrF,-ThF,-UF, mixture 

at 700°C produced only a slight surface 

roughening of the brazing alloy. 

Surprisingly, no cracking - which often 

occurs in graphite-metal brazed joints due to 

differential thermal expansion/contraction 

of the metallic and non-metallic parts - was 

observed in this case. This was attributed to 

the fact that the thermal expansion coefficient 

of molybdenum is only slightly larger than that 

of graphite. It is claimed, in fact, that by 

using molybdenum inserts, or so-called 

‘transition’ pieces, crack-free joints can be 

made with the Pd-Ni-Cr alloy between 

graphite and metals with high thermal ex- 

pansion coefficients. 

Although the new alloy was developed as a 

special purpose material, there is no doubt 

that palladium-base alloys of this kind would 

prove useful in general engineering applica- 

tions in which a high strength and good 

resistance to corrosion and oxidation at both 

room and elevated temperatures are important 

considerations. 

M.H.S.

The Structure of Supported 

Platinum Catalysts 

EXAMINATION BY ELECTRON MICROSCOPY 

By R. L. MOSS, M.Sc., Ph.D. 

Ministry of Technology, Warren Spring Laboratory 

Modern techniques are steadily increas- 

ing our knowledge of the structure and 

properties of the supported platinum 

metal catalysts so widely used in 

chemical processing. The main func- 

tion of the support, such as charcoal, 

alumina or silica, is to increase the 

surface area of the platinum metal and 

so to enhance catalyst performance, and 

methods for studying the dispersion of 

the platinum are therefore of consider- 

able importance. This article describes 

the application of electron microscopy 

to the problem and compares the results 

given by this and other methods. 

The study of the state of dispersion of the 

metal in supported platinum catalysts is based 

on indirect methods such as gas chemi- 

sorption, and on direct methods such as 

X-ray diffraction and electron microscopy. 

The chemisorption method depends on 

finding conditions of temperature and pres- 

sure at which a gas-hydrogen or carbon 

monoxide-will chemisorb to monolayer 

coverage on the platinum but not on the 

support. The volume of gas taken up shows 

the extent to which the platinum has been 

dispersed. For example, it was shown (I) 

that a freshly prepared reforming catalyst 

(0.6 wt. per cent platinum on ?-alumina) had 

most of the platinum atoms exposed, probably 

as islands or as very small crystallites less than 

10 a in size. There is, however, a growing 

awareness that the performance of supported 


metal catalysts (diffusion limitations apart) 

may be related not only to the metal area but 

to the actual size of the metal crystallites 

responsible for that area. The latest standard 

electron microscopes can resolve the smallest 

aggregates of platinum atoms which may be 

described as crystallites and hence provide 

valuable information on the sizes and numbers 

of crystallites present. Further, the distribu- 

tion of platinum throughout the support and 

characteristics of the support itself may be 

examined. 

Appearance under the Electron 

Microscope 

Suitable specimens for electron microscopy 

can be prepared by cutting extremely thin 

sections (300 to 500 A) with an ultra-micro- 

tome from catalyst particles embedded in, 

for example, “Araldite”. An alternative 

method is ultrasonic dispersion of the 

catalyst in butyl alcohol. Remembering the 

very small area under examination, a number 

of specimens must be prepared and surveyed 

in order to obtain representative electron 

micrographs. 

Platinum/Silica 

Fig. I shows an electron micrograph of a 

3 per cent platinum/silica catalyst made by 

impregnating silica gel with chloroplatinic 

acid solution, drying at 120°C and reducing 

in hydrogen. At a magnification of IOO,OOO X , 

the platinum shows up as dark spots evenly 

distributed as minute crystallites in the pore 

system of the silica gel. Electron diffraction 

patterns from selected areas with a high

concentration of dark spots confirm the 

presence of platinum. 

About 1000 platinum crystallites in this 

electron micrograph were sized in terms of 

their diameters, since they appear approxi- 

mately spherical, in increments of 10 A, and 

Fig. z shows the number of crystalljtes 

observed in each size range. The crystallites 

Platinum Metals Rev., 1967, 11, (4) 1 42 

Fig. 1 3per centplatinunt/ 

silica catalyst, magnifica- 

tion 100,000 X, showing 

platinum crystallites as 

dark spots on grey silica 

background 

are predominantly in sizes below about 50 A; 

in the 10 A size crystallites most of the 

atoms (datomic =z.77 A) are “surface” atoms. 

Although the 10 to 50 A crystallites account 

for only one-quarter of the total weight of 

platinum present on the support, nevertheless 

they provide almost half of the available 

platinum area. Hence the platinum pri- 

marily responsible for the performance of this 

supported catalyst can be “seen” by electron 

microscopy. 

Electron micrographs of the silica support 

itself showed spherical particles of, very 

roughly, IOO a diameter. Assuming no loss 

of area when the particles contact, the cal- 

culated surface area is -250 m2/g. This 

rapid estimate agrees reasonably with the 

BET gas adsorption value. 

Platinum/Charcoal or Alumina 

Fig. 3 shows an electron micrograph of a 

platinum on charcoal catalyst at a magnifica- 

tion of IOO,OOO A. Chemisorption methods 

showed the very high platinum area of a 

Johnson Matthey 5 per cent platinum/ 

charcoal catalyst which formed the basis of the 

sample examined. The catalyst was then 

subjected to a vigorous sintering treatment 

(firing at 300°C in air) to encourage crystallite 

growth. Nevertheless, as the electron micro- 

graph shows, the platinum crystallites were

Fig. 3 Sper centplatinuml 

charcoal catalyst, heated in 

air at 300”C, magni5cation 

100,000 X, showing very 

small platinum crystallites 

still very numerous and extremely small in 

size, yielding a large catalytically-active 

the relation existing between the number of 

gas molecules adsorbed at this point and 

the number of surface metal atoms. 

platinum surface. 

Fig. 4 shows an electron micrograph 

(35,000 X) of a catalyst with 2.5 per cent 

platinum supported on a low-area alumina. 

Measurement of the platinum area by carbon 

monoxide chemisorption showed that it was 

closely similar to the area of the platinum/ 

silica catalyst discussed above (Fig. I), but 

the electron micrographs are in marked 

contrast. Whereas the platinum crystallites 

in the silica-supported catalyst are widely 

distributed, this alumina-supported catalyst 

shows dark patches of platinum. At still 

higher magnifications ( IOO,OOO x ), these 

patches were clearly resolved as groups of 

small platinum crystallites (Fig. 5) and the 

platinum area is obviously higher than it 

might at first seem. 

The equipment required (2), however, is 

relatively simple, for example, a conventional 

volumetric apparatus such as might be used 

for BET surface area determinations, a 

vacuum micro-balance or a flow system linked 

to a gas chromatograph. If the observed 

metal area is S, the mean crystallite size, d,, 

is calculated from dS=6/Sp where p is the 

density of the metal; it is assumed that the 

crystallites are spheres or any regular polyhedron 

except the tetrahedron. This diameter, 

d,, is the surface-average diameter 

defined by Cnidt/Cnid,2, where there are ni 

crystallites of diameter, di. From the crystallite 

size distribution (Fig. 2) obtained from 

electron micrographs the diameter, d,, is 

readily calculated for comparison with the 

mean size obtained by chemisorption. 

Comparison with Chemisorption 

The determination of crystallite size by 

X-ray diffraction depends on the fact that 

and X-ray Diffraction 

below about 1000 A size, X-ray reflections 

The chemisorption method for measuring are broadened beyond the normal ‘‘instruthe 

metal area of a supported catalyst has mental” breadth. Thus the method involves 

already been briefly discussed. Its main measuring the breadth of one or more X-ray 

problems are : 

reflections, preferably using an X-ray counterchemisorbing 

gas on the metal but not on the 

support; 

difiactometer which provides a chart-recording 

of the position, profile and intensity of 

choice of a criterion for monolayer coverage; each reflection. The Scherrer equation relates 


Fig. 4 A 2.5 per cent platinumlalumina 

catalyst, magnification 35,000 >( , showing plat- 

inum as dark patches 

the excess breadth to the mean crystallite 

size, 6, which is a volume-weighted average 

diameter, Cnidt/Cnidt. Again, this type of 

average diameter can be calculated from 

electron microscope observations for comparison 

with X-ray results. The main problems 

with the X-ray diffraction method are: 

the smaller platinum crystallites, perhaps 

those less than 50 A, when measured with 

standard equipment, are not detected yet 

provide much of the available platinum 

area of the catalyst. The proportion of 

platinum remaining undetected can, how- 

ever, be estimated (3); 

crystallite size is measured whereas the plati- 

num can be present as particles, that js, 

agglomerates of crystallites, with interior 

surfaces inaccessible to gas molecules, 

With the problems involved in measuring 

crystallite size (and platinum area) by 

chemisorption or X-ray diffraction, it is there- 

fore of some interest to compare such results 

with the crystallite size distribution obtained 

from electron micrographs. This has been 

Fig. 5 Same catalyst, magni$cution 100,000 X , 

resolving individual platinum crystallites 

done for the 3 per cent platinum/silica 

catalyst (Figs. I and z), taking into account 

the different types of average involved, with 

the results shown in the table. Some satis- 

factory conclusions can be drawn from these 

results : 

the assumptions involved in the chemisorption 

method (carbon monoxide at 25OC, COiPt 

ratio=^, no adsorption on silica) seem 

reasonably justified; 

the electron microscope resolved most of the 

platinum crystallites contributing to the 

platinum area; 

the ‘particles’ viewed in the electron rnicro- 

scope were also the crystallites detected by 

X-ray diffraction. 

Relation to Catalyst Performance 

There are two important consequences, 

at least, for catalyst performance arising 

from an increase in crystallite size, perhaps 

as a result of sintering during use. 

The more obvious is the rapid loss in metal 

area accompanying crystallite growth. The 

Average Crystallite Size in 3 per cent Platinum-Silica Catalyst 

Mean diameter, d,, of all crystallites: 

by chemisorption 45 A 

by electron microscopy 55 A 

Mean diameter, d,, of crystallites 50 A size and above: 

by X-ray diffraction 60 A 

by electron microscopy 65 A 


Fig. 6 Models of small 

platinum crystallites: 

left-hand represents 

approximately 10 A 

diameter with mainly 

(111) crystal planes ex- 

posed; right-hand re- 

presents approximately 

I2 A with predomi- 

nantly (100) planes ex- 

posed 

left-hand model in Fig. 6 represents a very 

small crystallite, - 10 A diameter, containing 

38 atoms ofwhich 31 are exposed (82 per cent), 

excluding those which only contact the sup- 

port. The slightly larger right-hand model, 

-12 A diameter, represents 62 atoms but 

now only 44 (71 per cent) are present at the 

surface. One important factor in choosing the 

support material is the stability which it can 

impart to the crystallites against sintering 

together. 

Further reference to the models (Fig. 6) 

shows a less obvious consequence of crystallite 

growth. Whereas the smaller crystallite 

displays mainly (I I I) crystal planes, addition 

of a single layer of atoms to.form the slightly 

larger crystallite yields a surface with pre- 

dominantly (100) planes exposed. As these 

small crystallites grow, other crystal planes 

and atomic arrangements rapidly form and 

change, each with its characteristic catalytic 

properties. For example, when n-heptane 

was reformed over a series of platinum/ 

alumina catalysts (4, dehydrocyclisation 

activity was decreased and isomerisation in- 

creased as the mean crystallite size varied 

from 10 to 450 A. 

Some applications of the electron-micro- 

scope to supported catalyst research are 

therefore apparent. 

(i) When the performance of a supported 

catalyst is being assessed, often the 

metal area is measured in order to 

report the specific activity, that is, 


activity per unit metal area. Now a 

further step forward would be to record 

the structure of the catalyst, at least in 

part, by determining the crystallite 

size distribution from electron micro- 

graphs. 

(ii) Apart from duofunctional reforming 

catalysts where both platinum and 

alumina provide catalytically active 

sites, it is believed that the specific 

activity may sometimes be altered by 

the nature of the support. This means 

that, in addition to its traditional roles 

which include extending the metal 

area, the support co-operates somehow 

in the catalytic process. However, 

changing the support can alter the 

crystallite size distribution and again 

electron micrographs may help to 

disentangle the effects of crystallite size 

and support on catalyst performance. 

Acknowledgement 

The author wishes to acknowledge the con- 

tribution of Miss J. Holroyd who prepared the 

electron micrographs used to illustrate this article. 

References 

I L. Spenadel and M. Boudart,J. Phys. Chem., 

19601 64, 204 

2 R. L. Moss, The Chemical Engineer, 1966, 

(1991, (June), CE 114 

3 T. A. Dorling and R. L. Moss, J. Catalysis, 

1966,5, 111 

4 H. J. Maat and L. Moscou, in Proceedings of 

the Third International Congress on Catalysis, 

Amsterdam, 1964, p. 1277 (Amsterdam: 

North-Holland Publ. Co, 1965)

The Platinum Metals in Catalysis 

PAPERS AT THE SECOND CANADIAN SYMPOSIUM 

The second Symposium on Catalysis 

organised by the Canadian Institute of 

Chemistry was held in June at McMaster 

University, Hamilton, Ontario, and was well 

attended by workers mainly from Canadian 

industries and universities. Of the twenty- 

eight papers presented, covering a very wide 

range of subjects, some eight or nine had 

relevance to the use of platinum metals in 

heterogeneous and homogeneous catalysis, 

including two on electrocatalytic phenomena. 

The electrochemical behaviour of gold- 

palladium alloys was described in a paper 

by T. J. Gray, R. Rozelle, A. Schneider and 

M. L. Soeder (Alfred University, New York 

State); by studying alloys containing about 

12, 26, 44, 62 and 68 per cent gold, the 

authors established that the maximum rate of 

hydrogen occlusion occurred with the 26 per 

cent gold alloy, for which the H/Pd ratio at 

the rest potential (32 mV) was 0.042. Alloys 

containing 12 and 44 per cent gold did not 

achieve rest potentials (indicating lower rates 

of occlusion), while the alloy having 68 per 

cent gold behaved similarly to pure gold. The 

observations reported by D. J. G. Ives, 

F. R. Smith, P. D. Marsden and J. B. 

Senior, of Birkbeck College, on the cathodic 

activation of mercury-poisoned platinum and 

of gold strongly suggested that the desorption 

of hydrogen atoms is retarded on these 

inactive surfaces. 

The mechanism of the exchange of liquid 

saturated hydrocarbons with deuterium cata- 

lysed by supported platinum metals differs 

substantially from the corresponding gas 

phase processes. J. G. Atkinson, M. 0. 

Luke and R. S. Stuart, of Merck, Sharp and 

Dohme, Montreal, disclosed that in the 

liquid phase systems the exchange is pre- 

dominantly stepwise, and by continually 

passing pure deuterium through the liquid 


hydrocarbon in which the catalyst was sus- 

pended they were able to achieve complete 

substitution of all the hydrogen atoms. 

R. J. Harper and C. Kemball, of Queen’s 

University, Belfast, compared the behaviours 

of palladium and platinum with those of 

nickel and tungsten in the exchange of a 

series of mono-halogenated benzenes with 

deuterium. The exchange rates, which 

decreased in the sequence of increasing 

atomic number of the halogen (iodobenzene 

could not however be studied), were all 

slower than for benzene itself. The noble 

metals were less poisoned by the small 

amount of halogen cleaved from the ring than 

were the base metals. 

The development of a new PkItinUm-On- 

alumina catalyst having high activity and 

selectivity for the isomerisation of n-hexane 

was described by W. J. M. Pieters and 

G. C. A. Schuit, of the Technical University, 

Eindhoven. It is well established that treat- 

ment of platinum on alumina with carbon 

tetrachloride at elevated temperatures forms 

a surface layer of aluminium chloride which 

greatly increases the activity of the catalyst 

for isomerisation. However, Pieters and 

Schuit were able to show that selectivity 

could also be improved by controlled poison- 

ing of the platinum by thiophene. 

G. C. Bond (Johnson Matthey) reviewed 

the hydrogenation of acetylene catalysed by 

the platinum group metals. The ability of 

palladium to hydrogenate acetylene selectively 

to ethylene in the presence of a large excess of 

ethylene was attributed to its ability to become 

rapidly and selectively poisoned for ethylene 

hydrogenation. The addition of deuterium to 

acetylene over palladium and platinum 

catalysts gives about 80 per cent of cis- 

C,H,D,, rhodium and iridium giving a 

broader distribution of deuterated ethylenes.

Two of the contributions dealt with homo- 

geneous catalysis by platinum metal com- 

pounds. P. R. Rony, of Monsanto, St Louis, 

gave a theoretical treatment of supported 

catalytic solutions, and showed that there 

should exist an optimum liquid loading for 

efficient catalysis. The system had been dis- 

covered independently by workers in both the 

Monsanto Company and the Johnson Matthey 

Research Laboratories (G. J. K. Acres, 

G. C. Bond, B. J. Cooper and J. A. Dawson, 

J. Catalysis, 1966, 6, 139). 

Iridium Coatings in Ion Engines 

HIGH WORK FUNCTION AND THERMAL STABILITY 

In their traditional miserly role, metals 

with a high work function are reluctant to 

part with electrons although when heated 

they accept them with great alacrity from 

materials of lower electron affinity. As an 

electron acceptor iridium is now being 

seriously considered as an improved ioniser 

material for use in caesium ion engines. This 

work is being carried out under the auspices 

of NASA by the Hughes Aircraft Company 

Research Laboratories, Malibu, California, 

and a recent report by R. R. Turk and W. E. 

McKee (I) describes some of the preliminary 

results obtained. 

Thrust is obtained in these ion engines by 

the reaction of a stream of electrostatically 

accelerated caesium ions and an appreciable 

un-ionised flux rapidly destroys the accelerat- 

ing electrodes. Although solid tungsten has 

been used as an ioniser it is easily flooded by 

the high flow rates of caesium now normally 

employed. 

Porous tungsten with its high surface area 

is less liable to flooding but is unfortunately 

somewhat unstable and loses its permeability 

at the normal temperature of operation 

involved in these devices. 

Attempts to produce complete ionisers of 

higher work function and improved thermal 

stability involved powder metallurgy studies 

on iridium and rhenium alloys. Porous com- 

pacts based on the 50 per cent iridium, 50 

per cent tungsten composition had the hex- 

agonal epsilon crystal structure and a high 

resistance to densification. Economic and 

practical considerations finally indicated that 

better results would be obtained by the appli- 


The various products obtained from the 

reaction of disubstituted acetylenes with 

palladous chloride were listed by P. M. 

Maitlis of McMaster University; in non- 

hydroxylic solvents, hexaphenyl-benzene is 

obtained almost quantitatively from diphenyl- 

acetylene. Dimethylacetylene in methylene 

chloride solution on the other hand reacts with 

palladium chloride to give only about 10 per 

cent of hexamethylbenzene, the remainder of 

the product being polymeric in nature. 

G. C. B. 

cation of thin layers of iridium and rhenium 

to porous tungsten substrates. 

Iridium coatings were obtained by spraying 

dilute solutions of iridium trichloride on to 

heated tungsten compacts which were sub- 

sequently reduced in hydrogen. Half-micron 

coatings of iridium so obtained were stable 

for at least 200 hours in vacuum at 1500°C 

and work functions of 5.28 f 0.03eV were 

measured on such deposits. 

Electroplated rhenium surfaces were also 

effective. Although the work function of 

5.20eV I 0.03 determined for rhenium was 

comparable to that of iridium, it was found 

that rhenium, because of its high solubility 

in tungsten, provided a less stable coating 

than iridium. 

Much further work will be required before 

the true effectiveness of these noble metal 

coatings can be properly assessed. It is inter- 

esting to speculate, however, upon the way in 

which osmium might behave under such 

conditions. The work function of osmium has 

been recently determined (2) as 5.93 rt 0.05eV 

a value higher than that of iridium and rhen- 

ium. Osmium also forms a carbonyl which 

might facilitate the deposition of uniform thin 

deposits on the tungsten substrate. 

A. S. D. 

References 

I R. R. Turk and W. E. McKee, “Alloy Ioniser 

Fabrication”, NASA Contract No. NAS 3 - 

6272, Hughes Aircraft Company, Malibu, 

California 

z P. Zalm and A. J. A. Van Stratum, Philips Tech. 

Rev., 1966, 27, (3/4) 69-75

Carbonyl Halide Complexes 

of the Platinum Metals 

By M. J. Cleare, B.s~., A.R.C.S. 


The many advances in the chemistry of the 

platinum metals made in recent years have 

been particularly evident in the field of 

carbonyl group-containing complexes. Improved 

methods of preparation have been 

developed and the uses of such complexes 

in homogeneous catalysis have been and are 

being actively studied. 

The preparation of these carbonyl halide 

complexes by a variety of techniques has been 

reported. The production of ruthenium 

complexes by the decarbonylation of formic far, been reported. 

acid by ruthenium (11) species has been 

studied (I) and there are reports of the 

reaction of [IrC1,I3- or [IrClJ- with formic 

acid to yield carbonyl halide species of un- 

certain formulae (2,3). Ruthenium complexes 

have been prepared by the long passage of 

carbon monoxide through solutions of ruthen- 

ium (111) halogen compounds (4) and iridium 

complexes by the reaction of halogen com- 

pounds with carbon monoxide under pressure 

(5). Similar osmium compounds have not, so 

Carbonyl Halide Complexes of Osmium, Ruthenium and Iridium 

I Complex Colour Reactants Time 

Infra-red C - 0 

Stretching Frequencies 

cm-1 

Cs,(Os(CO)Cl,) Orange (OsC1,)2-+H.COOH Can be found 

from &5 hr 

1968~s 

Cs,(Os( CO) &1,) White (OsC1,)’-+H.COOH -8-9 hr 2014vs 189gvs 

or OsCl,+H.COOH (2037) (1947) 

Cs 2( Os(C0) pBrp) Yellow (OsBr,)2-+H.COOH -12 hr 2005vs 189gvs 

Cs(0s(CO),Cl3) White (OsC1J-iH.COOH -48 hr 2125vs 2046vs 

OsCl,+H.COOH 2014vs 2031sh 

2023sh xggzm 

(2128) (2039) 

Cs(Os(CO),Br,) White (OsBrJ-+H.COOH -60 hr z1zovs2048vs 

2017vs xgg6sh 

Cs,(Ru(CO)(H,O)Cl,) Green (RuC1,(H,O))S-+ I hr 

H.COOH 

RuC1, +H.COOH 

Yellow 

Ig’jIVS 

Cs,(Ru(CO),Br,) Yellow- (RuBr,(H,0))2- + -6 hr ZOjZVS I932VS 

Green H.COOH 

RuBr, +H.COOH 

Yellow RuCI,+H.COOH 7 hr 2076vs z018vs 

Pink- (IrCl,)e-+H.COOH 2-3 min 2070vs 

Yellow (IrCl,)a-+H.COOH 

Cs,(Ir(CO)BrJ Orange (1rBrJ3--l H.COOH 2-3 min 2038vs 

Infra-red spectra run on Nujol mulls; frequencies in parenthesis in aqueous solution 

Platinum Metals Rev., 1967, 11, (41, 148-149 148 

ZOjZVS I932VS

Recent investigations into the reactions of 

platinum metal compounds with formic acid 

have led to the discovery of a new and convenient 

method of preparing carbonyl halide 

complexes of osmium, ruthenium and iridium 

by refluxing the metal halide or halo-complex 

with go per cent formic acid (6). The compounds 

formed were initially recognised as 

carbonyl rather than formate complexes by 

infra-red spectroscopy in the 2000 cm-l 

region. 

The complexes that have so far been prepared 

and the reaction conditions are set out 

in the table opposite; all the compounds have 

been characterised by elemental analysis and 

their full infra-red spectra have been determined 

and recorded, 

To isolate salts of the anionic species it was 

found necessary to use caesium as the cation 

since lighter atomic weight alkali metals 

yielded salts of very high solubility. 

The reaction between sodium hexachlorosmate 

(IV) (used because of the low solubility 

of other [OSC~,]~- salts) and formic acid is of 

particular interest since it takcs place much 

more slowly than those between ruthenium 

and iridium compounds and formic acid. 

This has made it possible to identify by infrared 

spectroscopy intermediate formato-halo 

species containing one and two monodentate 

formate groups. These species probably 

contain formally divalent osmium, that is 

[Os"(COOH)C1,]4- and [Os11(COOH),C1,]4-, 

and they further react to give the mono- and 

dicarbonyl species respectively. The reaction 

proceeds quickly to the diformate stage and 

the monocarbonyl complex is formed in small 

quantities only. 

Triphenylphosphine derivatives are easily 

prepared by warming the complexes with 

triphenylphosphine in formic acid solution or, 

more conveniently, by treating the solutions 

prior to isolation of a carbonyl halide salt 

with triphenylphosphine. The complexes 

[OS(CO> 2(PPh,)ZXZI and [OGO) 3PPh3)XzI 

have been prepared from Cs,[Os(CO),X,] 

and Cs[Os(CO),X,] respectively, while 

[Ru(CO)d'Pha)&J and [Ru(CO)(PPhJ&lzI 

have been prepared from Cs2[Ru(CO),X4) 

and Cs,[Ru(CO)(H,O)Cl,] respectively (X = 

C1, Br). 

The author's thanks are due to Dr W. P. 

Griffith of Imperial College of Science and 

Technology for help and guidance in this 

work. 

References 

I J. Halpern and A. W. L. Kemp,J. Am. Chem. 

SOC., 1966, 88, 5147 

2 I. I. Chernyaev and 2. M. Novozhenynk, 

Russ. J. Inarg. Chem., 1966, 11, 1004 

3 Y. Y. Kharitonov, G. J. Majo and Z. M. 

Novozhenynk, Bull. Acad. Sci. U.S.S.R., 1966, 

1072 

4 J. Halpern, B. R. James and A. W. L. Kemp, 

J. Am. Chem. Sac., 1966, 88, 5142 

5 L. Malatesta, L. Naldini and F. Cariati, 

J, Chem. Sac. 1964,961 

6 M. J. Cleare and W. P. Griffith, Chem. and 

Ind., in the press 

Performance of Platinised Titanium Anodes 

The use of platinised titanium as a counter 

electrode in cathodic protection is well 

established, even though a detailed mechan- 

ism for the excellent performance of these 

anodes is not fully documented. A recent 

investigation of this subject by P. Van Laer 

and J. Van Muylder of CEBELCOR, pre- 

sented as a paper to the CITCE colloquium 

on Corrosion and Electrochemical Thermo- 

dynamics held in Istanbul in September, is 

of some considerable help in this direction. 

Anodic polarisation studies in synthetic sea- 

water, using current densities in the range 

o to 600 mA/cm2, showed that if corrosion of 


the titanium is to be avoided the anodic 

potential must not exceed +7.0 VSCE. 

Further, the authors state that at potentials 

above +2.1 VsC~ modification of the 

platinum surface occurs, and studies in the 

range $1.3 to 1.4VsCE suggest that oxidation 

of platinic oxide PKO, to perplatinic oxide 

PtO, may take place. 

It was concluded that the long life of 

platinised titanium anodes in sea-water is due 

to the titanium surface being protected from 

high current densities by the platinised areas, 

thus ensuring that the potential does not 

exceed the threshold of danger. J. H.

ABSTRACTS 

of current literature on the platinum metals and their alloys 

PROPERTIES 

Low-energy Electron-diffraction Study of 

the Clean (loo), (lll), and (110) Faces of 

Platinum 

H. B. LYON and G. A. SOMORJAI, 3. Chem. Phys., 

1967, 46, (7)2 2539-2550 

The (IOO), (rrr) and (110) faces of a “clean” 

Pt single crystal were studied as a function of 

temperature by LEED techniques in ultra-high 

vacuum. At low temperatures (111) and (100) 

show several ordered structures stable within a 

well-defined temperature range ; the (I 10) face 

shows faceting above 600°C. Above 750°C a 

new stable phase is formed irreversibly on all 

three faces and is characterised by a ring diffrac- 

tion pattern which increases in intensity as the 

m.p. of Pt is approached and is due to domains 

of (I 11) surface structure. 

Surface Self-diffusion of Nickel and Platinum 

A. J. MELMED, J. Appl. Phys., 1967, 38, (4), 

1885-1892 

Field-electron emission spectroscopy of Pt at 

550450°K indicated an Arrhenius-type relationship 

between temperature and time, so that 

activation energies of surface rearrangement could 

be derived: Qf=26.3*2.6 kcal/mole in the range 

(27-39) x 106 V/cm for electric field build-up; 

zero field activation energy is calculated as 

29.7 j 3 .o kcal/mole ; Qo = 29.5 & 3 .o kcal/mole 

for surface tension (annealing). Either type of 

measurement is satisfactory to k 10%. 

Platinum Oxidation Kinetics with Convective 

Diffusion and Surface Reaction 

R. w. BARTLETT,~. Electrochem. SOC., 1967, 114, 

(6)J 547-550 

An analysis of the oxidation kinetics of Pt con- 

sidered how the oxidation rate is affected by the 

reversible surface reaction 02+Pt z? Pt02(g) 

and by transport of the oxide vapour through a 

gaseous boundary layer, and derived mass transfer 

coefficients for oxide vapour diffusion, the 

forward and reverse specific rate constants for 

steady-state surface oxidation, and oxidation rate 

curves at various pressures and temperatures. 

Ideal Resistivity of Platinum below 20°K 

R. J. BERRY, Can. J. Phys., 1967, 45, (5), 1693- 

1708 

The electrical resistivity of ideally pure Pt may be 

represented by a T2 (electron-electron) scattering 

Wi~=piT‘-kqiT’ and WiT is the resistance 

ratio Ri~iRi 273.15 at T”K. Accurate measurements 

were made on Pt used for resistance 

thermometry. The two-band model was used to 

correct small but significant impurity scattering. 

The temperature dependence of the “ideal” 

resistivity function was compared with theory 

and previous work and some discrepancies were 

noticed. 

Thermal Conductivity of Selected Materials 

U.S. Nat. Bur. Stds NSRDS-8, 1966, (Nov.), 

9-10> 45-50 

Among the materials reviewed are Pt and 40% 

Rh-Pt. Curves for the variation of thermal 

conductivity with temperature are derived from 

work reported in the literature. Further work is 

needed to define the curves more accurately. 

Heat-resistance of Platinum, Palladium and 

their Alloys 

E. I. RYTVIN, v. M. KUZ’MIN and A. E. PETROVA, 

Metulloved. term. Obrabot. MetaE., 1967, (z), 31-32 

25y0Pd-Pt had the greatest heat-resistance of 

Pt, Pd, Rh-Pt and Pd-Pt samples tested at 1200- 

1400°C with 0.5-X.O kg/mma axial stresses. 

Time-to-failure was recorded as a measure of 

heat-resistance and curves for Pd-Pt showed 

sharp maxima, particularly at lower temperatures. 

Deformation and Fracture of Gold-Platinum 

Polycrystals Strengthened by Spinodal Decomposition 

R. W. CARPENTER, Acta Metall., 1967, 15, (8), 

1297-X308 

Study of the deformation and fracture character- 

istics of 60% and 20% Au-Pt, strengthened by 

spinodal decomposition, shows that both the 

proportion limit and the work-hardening rate, 

which is initially higher than normal, increase on 

isothermal ageing. The proposed theory for the 

work-hardening behaviour agrees well with 

the experimental results. Fractures are due to 

the formation of Pt-rich and Au-rich precipitates 

in the intergranular regions of the 60% and 20% 

Au-Pt alloys respectively. 

Oxidisability of Alloys of Platinum with 2.5 

and 8.50/, Copper during Heating in Air 

E. A. KUZNETSOV and D. V. IGNATOV, Zh. Neorg. 

Khim., 1967, 12, (6), 1463-1465 

Samples of 2.5 and 8.5% Cu-Pt sheet were heated 

at 100°C intervals up to 600°C and electron 

term plus a second term proportional to T4*7*0*2 diffraction tests showed the nature of the oxidain 

the range 7-17’K and to -T4.7*0*5 in the tion film. CuO was detected at 300°C and above. 

range 3-7”K, where the general relation is Traces of CuFe20, were detected at 500°C for 

Platinum Metals Rev., 1967, 11, (4), 150-159 150

2.5:/;, Cu-Pt and at 600°C for both alloys. No 

oxidation was detected at IOO or 200’C. 

The Effect of the Occlusion of Hydrogen on 

the Characteristic Temperature of Palladium 

and the Vibration Amplitudes of its Atoms 

E. A. OWEN and E. w. EVANS, Br. J. Appl. Phys., 

1967, 18, (5), 605-609 

Measurement of the fall in intensity of reflection 

of X-rays with increasing temperature in gas- 

free pure Pd gives a characteristic temperature of 

-267OK compared to 270 and 275°K by specific 

heat and electrical conductivity methods. The 

characteristic temperature of Pd rises to 311°K 

with 0.7 at.% H, content. The r.m.s. displace- 

ment of Pd atoms at room temperature falls 

from 0.131 A for gas-free Pd to 0.113 A for Pd 

containing 0.7 at.% H,. 

Comparison of Hydrogen and Deuterium 

Solubility in Palladium-rich Alloys. Gold- 

Palladium 

A. MAELAND and T. B. FLANAGAN,?. Phys. Chem., 

1967, 71, (61, I95O--I952 

Plots of electrolytic absorption of D, in a series 

of Pd-Au alloys were similar to those obtained for 

H, except for a reduced potential for D, in the 

two-phase system. Equilibrium solubilities of the 

two isotopes were similar. AG and AH for the 

reaction was found to be increasingly negative 

with increased metal content in the two-phase 

region. 

The Effect of Plastic Deformation on the 

Resistivity and Hall Effect of Copper- 

Palladium and Gold-Palladium Alloys 

M. J. KIM and w. F. FLANAGAN, Acta Metall., 

1967, 15, (5)> 735-745 

Electrical resistivity, measured as a function of 

composition and deformation for 25, 40, 65 and 

95 at.”:, Pd-Au and quenched 50% Pd-Cu alloys, 

shows an anomalous decrease in resistivity due 

to a change in the electronic structure from des- 

truction of short range order. The decrease is 

continuous for Cu-Pd which has a large short 

range order. For Au-Pd alloys, the decrease is 

followed by an increase as the effect of strain 

-induced defects eventually predominates. The 

anomalous decrease observed for the Hall effect 

is described similarly. 

An Approximate Density of States Curve 

and its Relation to the Measured Electrical 

Resistivity of Gold-Palladium Alloys 

Ibid., 747-752 

The resistivities of the Au-Pd system, described 

by a simple two-band model corrected for 

electron interaction, were measured by the Van 

der Pauw method at 90, 195, 273, 373, 413 and 

473°K. Density of states curves obtained from 

published values of paramagnetic susceptibilities 

and electronic specific heat coefficients predict 


0.52 holes for Pd as opposed to the calculated 

value of 0.55. 

The Recovery Kinetics of Deformed Copper- 

Palladium and Gold-Palladium Alloys 

Ibid., 753-763 

The recovery of a range of deformed Au-Pd and 

Cu-Pd alloys was studied by isochronal and 

isothermal annealing. The temperature of the 

annealing stages, which were similar to those 

obtained for pure metals, was found to be de- 

pendent on alloy composition. 

Relationships between the Hydrogen Content 

and Electrical Resistance of Palladium + 

Silver Alloys 

A. W. CARSON, F. A. LEWIS and W. H. SCHURTER, 

Trans. Faraday Soc., 1967, 63, (6), 1447-1452 

The relative electrical resistance, R/R,, and the 

temperature coefficient, cc, of ro-55 at.% Ag-Pd 

alloys were measured as a function of H content 

during the absorption and desorption cycles at 

25°C. The rate of decrease of R/R, with H/Me, 

the ratio of H atoms to the combined total of Pd 

and Ag atoms, increases with increasing silver 

content. The variation of 01 with H/Me is des- 

cribed in terms of the cc, phase structure of the 

alloys. 

Pressure-Composition Isotherms for the 

Pd+Ag+H System 

A. w. CARSON and F. A. LEWIS, Ibid., r453-1457 

The pressure-composition isotherms (hydride 

vapour pressure/(H/Me)) for the absorption 

of H, in 0-55 at.%, Ag-Pd electrodes at 25°C 

exhibit “plateau” regions for alloys containing 

>30% Ag where the 01- and P-phases coexist. A 

graph of isobaric solubility, (H/Me) against 

at.% Ag, shows that the solubility of H, as a func- 

tion of the Ag content is dependent on the H 

pressure at which the solubilities are measured. 

Mechanical Properties at High Temperatures 

of Ternary Conducting Alloys on a Silver 

Base 

N. L. PRAVOVEROV, A. N. BUBYREV and I. M. 

LOBYNTSEVA, Metalloved. term. Obrabot. Metal., 

1967, (2), 36-37 

Simultaneous addition of Pd with Cry Co or Fe 

greatly increases the mechanical strength of 

Ag at 20-300°C. Maximum effect occurs with 

Pd and Fe together; Pd plus Co and Cr gives 

almost as much effect. 0.4-0.5% Pd+o.o2%, of 

the other metal(s) are the most effective additions. 

Vaporisation Rates, Vapour Pressures and 

Heats of Sublimation of Rhenium, Rhodium, 

Palladium and Titanium 

H. STRASSMAIR and D. STARK, z. angew. Phys., 

1967, 23, (I), 40-44 

Results were obtained by Langmuir’s vacuum 

evaporation method for Rh at 1845-2092°K and

for Pd at 1361-1603°K and these are compared 

with previous work elsewhere. 

Effects of Mechanical and Thermal Treat- 

ment on the Structure and Magnetic 

Transitions in FeRh 

J. M. LOMMEL and J. s. KOWEL, J. Appl. Phys., 

1967,38, (311 1263-1264 

Well-annealed bulk FeRh samples exhibit a 

first-order antiferromagnetic-ferromagnetic trans- 

ition at 330-K but plastic deformation converts 

the normal CsC1-type structure to disordered 

f.c.c. structure, which is only weakly magnetic 

with no first-order transition. Annealing of the 

latter at 510°K converts it to highly-ordered 

CsC1-type structure. The return of the first- 

order transition occurs in three stages as perfect 

long-range order is achieved or as defects are 

annealed out. 

Magnetic Susceptibility and Specific Heat 

of Nearly Ferromagnetic NiRh Alloys 

E. BUCHER, W. F. BRINKMAN, J. P. MAITA and 

H. J. WILLIAMS, Phys. Rev. Letters> 1967,18, (25), 

1125-1127 

Nio.6aRho.a, is just on the ferromagnetic side of 

the critical concentration and has maximum 

magnetic susceptibility at -4o"K, and an anomalous 

specific heat below 8°K. The anomaly 

decreases on either side of this concentration and 

disappears at Nin.,5Rho.45 on the paramagnetic 

side, and at Nio.,oRho.30 on the ferromagnetic 

side. Plots of magnetic susceptibility and y values 

of specific heat were plotted against alloy concentration 

and confirm that 63O6 Ni is the critical 

value. 

The Crystal Structure of Hexagonal Rh2AI, 

L.-E. EDSHAMMAR, Acta chem. Scand., 1967, 21, 

(31, 647-651 

The structure of arc-melted, hexagonal Rh,AI,, 

determined by X-ray powder photography and 

evaluated using the least squares technique, 

belongs to the space group P6Jmrnc and has 

cell constants a-7.893 and c-7.854 a. It 

is compared with the apparently isomorphous 

Co,Al, structure. 

The Crystal Structure of IrAI, 

Ibid., (4), 1104-1105 

Single crystal, X-ray powder diffraction studies 

of IrAl, show that it has a DO,,-type structure 

and belongs to the space group P 6Jmmc with cell 

constants a=4.246 and c-7.756 A. The Guinier 

powder pattern data and the interatomic dis- 

tances are tabulated. 

New Phases in the Vanadium-Iridium 

System and a Tentative Constitution Diagram 

B. C. GIESSEN, P. N. DANGEL and N. J. GRANT, 

J. less-common Metals, 1967, 13, (I), 6270 

Crystal structures and approximate homogeneity 


ranges were established or confirmed for four 

intermediate phases in the V-Ir system and a 

tentative constitution diagram is proposed. 

VJr and VIr, were known previously; a-VIr and 

p-(VL-.JrX)Ir are new. Atomic volumes are 

given. 

Measurement of the Specific Magnetic 

Susceptibility of Osmium between 80 and 

1850°K by Means of an Improved Faraday 

Method 

w. D. WEISS and R. KOHLHAAS, Z. angew. Phys., 

1967, 22, (6), 476-481 

The specific magnetic susceptibility, x, of pure 

Os, determined by an electronically compensated 

microbalance with a relative resolving power of 

0.25 pg, was found to be 0.068 emulg at room 

temperature. The value of x between 80" and 

1850°K is given by x=(s~Kdx)i(2mH,S,,,), 

where m=mass of the probe and H, is the 

field component in the y direction. 

CHEMICAL COMPOUNDS 

Formation of Thin Films of PdO and their 

Electric Properties 

Japan. J. appl. Phys., 

n. OKAMOTO and T. ~$0, 

196796, (61,779 

Oxidation of evaporated Pd films in air at 973°K 

for 24 h formed thin PdO films. Electrical con- 

ductivity of PdO was measured as a function 

of temperature at 77-560°K in various atmos- 

pheres. It decreased on heat cycling. Energy 

gap, Hall coefficient and Hall mobility were 

studied also. 

Phase Relations in the Systems Ti02-Ir02 

and Sn0,-IrO, in Air 

c. L. MCDANIEL and s. J. SCHNEIDERJ. Res. N.B.S., 

Sect.A, Phys. Chem., 1967, 71A, (2), 119-123 

X-ray diffraction studies of the pseudobinary 

systems Ti0,-IrO, and Sn0,-IrO, after treat- 

ment in air for 18 h at 800, 900 and IOOOT 

indicated similar phase diagrams with no inter- 

mediate phases. Maximum solid solution of 

TiO, occurs with 5 mol.7" IrO, at 1040°C. 

Solid solution of TiO, in IrO, extends to 12 

mol.o/; TiO, at 1040"C, the dissociation tem- 

perature. Limited solid solubility of SnO, in 

IrO, exists to 3 rno1.x SnO, at 1025OC, the 

dissociation temperature. Solid solution in 

SnO, was not detected up to 1400°C. 

Thermal Dissociation of Iridium Trichloride 

N. I. KOLBIN and v. M. SAMOILOV, Zh. neorg. 

Khim., 1967, 12, (7), 1747-r750 

Investigations during the thermal dissociation 

of P-IrCl, and of mixed a- and P-IrCI, at 810- 

1040°K showed that no mono-p or dichloride of Ir 

coexists in these conditions. During the for- 

mation of IrC1, from its elements AH",,,,,, 

= -242.0k6.0 kJ/mole, AS",,,.,, == -242.0i8.0

J/"K. mole. For solid 1rCl3, So288.15 =127.0 

JPK. mole. The dissociation pressure is I atm 

at 1036°K. 

Carbon Disulphide, Carbonyl Sulphide, and 

Alkyl and Aryl Isothiocyanate and Per- 

fluorothioacetone Complexes of Nickel, Pal- 

ladium, Platinum, Rhodium, and Iridium 

M. c. BAIRD and G. WILKINSON, J. Ckem. SOL., 

A, inorg. phys. tkeor., 1967, (6), 865-872 

cs, reacts with Ph,P complexes of Ni, Pd, Pt, 

Rh and Ir in zero or +I oxidation states to form 

complexes with the CS, ligand r;-bonded, e.g. 

(Ph,P),PtCS,. Structurally-related z-complexes 

occur with COS and alkyl and aryl isothiocy- 

anates although the ally1 isothiocyanate-Pt com- 

plex is best formed otherwise. Isothiocyanates 

react with (Ph,P),RhCl to form both --bonded 

and donor co-ordinated complexes. Pt(PPh,), 

reacts with zJ2,4,4-tetrakis(trifluoromethyl)-~,3- 

dithietan and benzyl chloride to form (Ph31?),k 

(C,F,CS) and (Ph3P),PtC1(COPh) respectively. 

RhCl,(p-FC,H4N,)(PPh,)),,o.5CHCL, is des- 

cribed, 

Tris( triphenylphosphine)rhodium(I) 

Complexes 

W. KEIM, J. organometall. Chem., 1967, 8, (3), 

PZS-PZ~ 

Synthesis of u-bonded Rh(1) complexes contain- 

ing a Rh-C bond, i.e. methyltris(tripheny1- 

ph0sphine)rhodium and phenyltris(tripheny1phos- 

phine)rhodium, and of hydrotris(tripheny1phos- 

phine)rhodium are described. 'The compounds, 

characterised by IR and NMR, are all air-sen- 

sitive, soluble in aromatic solvents and decom- 

pose when heated to 150~-200"C. 

On the Polymorphism of Osmium Tetrachloride 

P. MACHMER, Chm. Commun., 1967, (IZ), 610 

Elemental analysis, X-ray powder diffractometry 

and magnetic measurements indicate the existence 

of two forms of OsC1,. A dark brown chloride, 

obtained from OsO, and SOCI,, appears to have 

a cubic lattice constant, a=9.95 A. It is paramagnetic 

and has a temperature dependent 

susceptibility. zmole= +880 x c.g.s. units. 

The black form, synthesised from its elements, 

can be represented by an orthorhombic unit cell 

with constants a=Iz.oS, b=11.96, and c= 

11.68 A. It is also paramagnetic but has a temperature-independent 

susceptibility of + 1080 x 

10-6 c.g.s. units. 

ELECTROCHEMISTRY 

Contribution to the Electrolytic Polishing 

of Platinum 

J. TOUSEK, CoU. Czech. ckem. Commlm., 1967, 

32, (6), 2348-2352. 

When a Pt electrode is immersed in a H,SO,/ 


HNO, mixture and a.c. is applied it dissolves 

fairly quickly, the rate of solution increasing with 

H,SO, concentration, but this tendency is 

limited by the easy formation of a passive oxide 

film which is difficult to reduce. Pt foil samples 

were produced by electrolytic polishing in a bath 

of equal volumes of 96% H,SO,, 65% HNO, 

and 8004 H,PO,. The rate of polishing at 0.5 

A/cmZ was about 3.1o-~g.crn-~s-l. 

Anodic Oxidation of Ethylene on Noble 

Metals and Alloys. Parametric and Isotopic 

Examination of Mechanisms 

A. T. KUHN, H. WROBLOWA and J. O'M. BOCKRIS, 

Trans. Faraday Soc., r967, 63, (6), 149-1467 

The anodic oxidation of C,H4 on the platinum 

group metals, Au, Ag, Hg and on the alloys 

Pd-Au, Rh-Pd, Cu-Rh, Cu-Au, Pt-Rh and Pt-Ni 

was determined in aqueous and deuterated 

electrolytes at 80°C. An estimate of the isotopic 

effect and several reaction mechanisms are sug- 

gested. The graph of rate of oxidation/heat of 

sublimation of substrate is described in terms of 

variable rates and rate determining steps. The 

treatment indicates why Pt is the superior 

electrocatalyst. 

Structure and Catalytic Activity of Platinked 

Platinum 

D. F. A. KOCH, Extended Abstr., rgrst Nat'l Mtg., 

Electrochem. SOC., 1967, (May), abstr. I74 

Studies on platinised Pt electrodes show that the 

surface area of Pt measured by H, adsorption in- 

creases with increasing weight of Pt deposited, 

indicating that pore areas are included in the 

determination, whereas capacitance measure- 

ments are confined to surface reactions. A 

decrease in Pt deposition potential results in a 

decrease in surface area of Pt deposited as the 

H, coverage is increased, which inhibits nuclea- 

tion and results in an increase in particle size. 

Catalytic activity below 0.5 V is oc surface area 

obtained by H, adsorption; at 0.67 V it is 

area determined by capacitance measurements, 

i.e. purely a surface reaction. 

Structural Studies of Porous Electrodes 

E. Y. WEISSMAN, J. Electrockem. Soc., 1967, 114, 

(7)J 658465 

Non-destructive measurements, used to determine 

surface area, porosity, pore size distribution, 

microporosity and polarisation curves 

of Pt black-Teflon-Ta screen electrodes, show 

that the micropores in the radii range 25-2ooA 

determine the performance. The structural 

geometry of the electrode was investigated with 

reference to electrochemical activity and can be 

represented by the equation i -=a exp (bS), where 

iycurrent density, S=surface area, a and b are 

constants depending upon the electrode and the 

experimental conditions.

Gold-Palladium Electrocatalysts 

J. H. FISHMAN and M. YARISH, Electrochim. Acta, 

1967, 12, (S), 579-581 

Homogeneous Au-Pd alloys containing 30-4Ou'h 

Au and 60-80% Au show significant changes 

in bulk characteristics due to d-band filling effect. 

The correlation between this effect and their 

catalytic properties is shown in the H,-0, 

oxidation reaction for which there is a maximum 

activity at 30% Au, falling off rapidly and ap- 

proaching zero at -7016 Au. Addition of Au to 

a Pd-H electrode in the presence of CO decreases 

the polarisation to a minimum at 40% Au; 

above 400: Au polarisation increases, indicating 

that the presence of Au increases resistance to 

CO poisoning. 

Pretreatment of Pt-Au and Pd-Au Alloy 

Electrodes in the Study of Oxygen Reduction 

A. DAMJANOVIC and v. BRUSIE, J. electroanal. 

Chem. interfacial Electrochem., 1967, 15, (I), 

29-33 

The effect of pretreatment of Pt-Au and Pd-Au 

electrodes in the form of wires sealed into a glass 

tube or threaded through a small Teflon cylinder 

were studied during 0,-reduction. 5% Au-Pt 

has the same Vilog i relationship whether 

treated chemically or thermally whereas elec- 

trochemical pretreatment gives a high activity 

for the reduction. Similar behaviour is observed 

for 80% Au-Pt ; electrochemical pretreatment 

produces behaviour similar to that of pure Pt; 

thermal and chemical treatment produces be- 

haviour similar to that of Au. The effect of 

thermal pretreatment of kinetics is discussed 

and the results are rationalised in terms of alloy 

composition and structure. 

Studies on the Electrochemistry of Osmium 

J. LLOPIS and M. VAZQUEZ, Anal. R. SOC. ESP. Fis. 

Quim., Ser.B, Quim., 1967,63, (3), 273-281 

Studies of the polarisation curves and anodic and 

cathodic charging curves of Os, electrodeposited 

on Pt from neutral solutions of Na,[OsCl,], 

show that anodic surface oxidation leads to 0s 

films being formed more than one molecule 

thick. In HCIO, electrolytes 0s is oxidised to 

soluble OsO, at 0.83 V; a similar effect is observed 

in HCl solution together with Cl, evolution. 

0~0,~- has been identified in alkaline electrolytes. 

ELECTRODEPOSITION AND 

SURFACE COATINGS 

An Apparatus for Heavy Rhodium Plating 

A. E. YANIV, Plating, 1967, 54, (6), 721 

Bright and smooth Rh deposits on silver-plated 

showed the high wear-resistance of contacts 

plated in this manner. The anode of the plating 

bath was platinised Ti expanded sheet. 

LABORATORY APPARATUS 

AND TECHNIQUE 

Criteria of Soil Aggressiveness towards 

Buried Metals. I. Experimental Methods 

F. H. BOOTH, A. w. COOPER, P. M. COOPER and D. S. 

wAKERLEY, Br. corros. J., 1967, 2, (3), 104-108 

The redox potential, EH at pH-7, as a factor in 

the aggressiveness of soil towards buried metals, 

was measured using a solid stemmed probe with 

duplicate Pt electrodes in the tip in conjunction 

with a saturated calomel reference electrode 

inserted in the soil I ft away from the probe. The 

mean potential of the duplicate electrodes, J?, 

was used to calculate EM using relationship, 

E~=E+0.250+0.060 [pH -71. 

Air Depolarised Electrolytic Oxygen 

Generator 

R. A. WYNVEEN and K. M. MONTGOMERY, J. Electrochem. 

SOC., 1967, 114, (6), 589-592 

Oa in ambient air is separated from N, and 

inert gases by reacting it at a cell cathode with 

simultaneous evolution of pure 0, at the anode. 

Both electrodes are Ni grids with a uniform 

surface layer of Pt black mixed with Teflon and 

the electrolyte is KOH solution. Performance 

depends on inlet air flow and pressure, and on 

moisture balance between H,O content of the 

air and the electrolyte vapour pressure. 

brass electrical contacts were obtained at SOT, Study of a Pilot Unit for Catalytic Reforming 

I A/dm2 to a thickness of IOF in H,SO, solution, 

after cleansing and activation. A jolting device 

prevented adhesion of bubbles. Abrasion tests 


- 

HETEROGENEOUS CATALYSIS 

The Problem of the Size of Platinum Losses 

in Nitric Acid Production 

H. SIKORA and E. BLASIAK, Przem. Chem., 1967, 

46J (4)> 199-z00 

The principal factors involved in the loss of 

Pt in HNO, production and some proposed 

improvements are discussed. 

Formation of PtO, - the Source of Platinum 

Losses in Nitric Acid Production 

H. SIKORA, J. KUBICKI and E. BLASIAK, Zbid., (s), 

257-258 

The loss of Pt in HNO, manufacture is now 

believed to be due to the evolution of PtO, 

rather than to evaporation of Pt. Its capture by 

CaO is effected by formation of a compound of 

the type xCaO.yPtO,, where x and y may equal I. 

This assumes that an essential step in the oxida- 

tion of ammonia is PtGPtO,. 

P. MAURET, A. KLEIN, J.-L. ABATUT and H. KOQUES, 

Chim. Znd., Gin. chim., 1967, 97, (IO), 165~-1658 

A pilot unit for the automation and optimisation

of catalytic Pt reforming using a digital computer 

has been set up at Institut National des Sciences 

Appliqukes, Toulouse. Incorporated are sensors 

developed to continuously measure octane num- 

ber, catalyst activity, as well as chromatographic 

analysis. Reported are first results of control 

techniques and of mathematical models applied 

to the problem. 

Development of a Mathematical Description 

of Platforming for Optimisation of the 

Process. 11. 

YU. M. KHOROV, G. M. PANCHENKOV, W. A. 

TIRAK'YAN, s. P. ZEL'TSER and P. R. FRADKIN, 

Kinetika i Kataliz, 1967, 8, (3), 658-662 

The differential form of the mathematical des- 

scription of Platforming is independent of the 

dimensions of the reactors. Optimum conditions 

were established by finding the limiting points 

from the mathematical relations. 

Structure and Activity of Noble Metal Alloy 

Catalysts. I. The Activity of Supported 

Rh-Pt Alloy Catalyst in the Hydrogenation 

of Aromatic Compounds 

K. YOSHIDA, Nippon Kagaku Zasshi, 1967, 88, 

(2), 125-129, A9 

The activity per unit wt. of alloy of supported, 

homogeneous Rh-Pt in the hydrogenation of 

C,H,, C,H,OH and C,H,COOH is shown to be 

a function of the alloy composition and has a 

maximum value of 20-400/; Rh-Pt. Results 

indicate that activity is dependent on electronic 

structure of the alloy and is independent of the 

reactant. 

11. State of Dispersion of Metal on the 

Supported Rh-Pt Alloy Catalyst 

Ibid., 220-222, A14 

Determination of the total surface area of catalyst, 

support and free metal for Rh-Pt dispersed on 

carbon black or activated charcoal by N, and CO 

adsorption at 77°K and 293"K, respectively, 

indicates that the catalyst is located in islands 

of several atomic layers on the carriers. This 

agrees well with X-ray diffraction data. 

111. Activity and Magnetic Susceptibility 

of Rh-Pt Alloy Catalysts 

Ibid., 222-224, A14 

Atomic susceptibility values of Rh-Pt alloys, 

measured with a Faraday balance at 25% follow 

the same pattern as their activities in hydrogenation 

of aromatic compounds, indicating that 

activity is due to unpaired d-electrons of the 

alloys. 

IV. The Role Played by Oxygen in the Action 

of Rh-Pt Alloy Catalyst in the Hydrogenation 

of Benzoic Acid 

Ibid., (3), 292-295 

A study of the gradual deactivation of Rh-Pt 

catalyst during the hydrogenation of aromatic 


compounds and its reactivation on contact with 

air indicates that adsorbed 0,, which appears to 

increase the number of unpaired d-electrons of 

the catalyst metal, is necessary to maintain high 

activity. 

V. Decrease in Activity of Rh-Pt Alloy 

Catalyst in the Hydrogenation of Benzoic 

Acid 

K. YOSHIDA, T. OTAKI and s. KOIKE, Ibid., 295-298 

The decrease in activity of Rh-Pt catalyst during 

the hydrogenation of C,H,COOH is shown to be 

due to the toxicity of metal ions in acid anhy- 

drides from the reactor and impurities in the 

C,H,COOH. A relationship between molecular 

size and poisoning strength is discussed. X-ray 

diffraction studies indicate that crystalline growth 

is too small to be responsible for the observed 

decrease in activity. 

Nylon-Platinum Catalysts with Unusual 

Geometric and Selective Characteristics 

D. P. HARRISON and H. F. RASE, Ind. Engng Chem., 

Fund., 1967, 6, (2), 161-169 

Catalysts prepared from H,PtCl, and Nylons 

66, 6 and 610 showed similar characteristics for 

C,H, hydrogenation and produced substantial 

amounts of the intermediate cyclohexene. Nylon 3 

-Pt became active at a higher temperature and 

only cyclohexane was produced. Nomex-Nylon- 

Pt was inactive. These differences are suggested 

as being due to an arrangement of Pt atoms cor- 

responding to the position of amide groups in the 

nylon crystal. Apparent interaction between 

Pt and the amide groups increases the efficiency 

of Pt compared to catalysts on inert supports. 

The Activity of Nylon-Platinum Hydrogena- 

tion Catalysts as Determined by the Struc- 

ture of Various Nylon Carriers 

D. P. HARRISON, Diss. Abstr. B, 1967, 27, (8), 

2691 

The isolation of cyclohexene over some of the 

catalysts in the hydrogenation of C,H, over 

Nylon 66, 610, 6, 3 or Nomex impregnated with 

H,PtCI, was explained by proposing a two point 

C,H, adsorption on the catalyst surface as sup- 

ported by kinetic evidence. Cyclohexene is not 

obtained using any other Pt catalyst with similar 

physical characteristics. The Pt-amide interac- 

tion between catalyst and carrier could not be 

confirmed due to insufficient sensitivity of 

apparatus. 

Growth of Single Crystals of Cadmium 

Chromium Selenide by Liquid Transport 

with Platinum Catalyst 

H. VON PHILIPSBORN, J. Appl. Phys., 1967, 38, 

(3), 955-956 

Pills of CdSe and CrCI, in close contact were 

heated at -700°C for three days in a Pt boat. 

Perfect octahedral single crystals of CdCr,Se,

grew in the CdSe by liquid transport, catalysed 

by Pt. 

Use of Atomic Absorption Spectrophotometry 

for the Study of Liquid-phase Adsorption 

Kinetics 

J.-M. VERGNAUD, B. REY-COQUAIS, B. BUATHIER and 

R. NEYBON, Bull. SOC. chim. Fr., 1967, (6), 2194- 

2196 

An atomic absorption spectrophotometer coupled 

to a reaction vessel, giving a response time of 

-I sec was used to study the liquid-phase adsorption 

kinetics of Pt/C or Pt/Al,O,. Initial 

adsorption rate and the adsorption limit could be 

measured also. 

Investigation of Liquid-phase Oxidation of 

Hydrocarbons on Solid Catalysts. I. Oxida- 

tion of Paraffins and Cycloparaffins 

N. v. KLIMOVA and I. I. IOFFE, Kinetika i Kataliz, 

r967, 8, (31, 565-571 

The catalytic activity of V,O,.WO,/Al,O, can be 

increased by the addition of Pt and other pro- 

moters. A heterogeneous-homogeneous mech- 

anism is assumed for the liquid-phase oxidation 

of the studied paraffins, cyclo-paraffins and 

aromatic hydrocarbons. It may be possible to 

control the process with different combinations of 

catalysts and inhibitors. 

Catalytic Properties of Platinum Catalysts. V. 

Effect of Alkali (KOH) on the Activity of 

Platinised Carbon 

K. H. SCHNABEL, Ibid., 583-591 

Small KOH additions increase the activity of 

Pt/C for C,-dehydrocyclisation but larger 

amounts poison it. Alkali gradually suppresses 

expansion of the ring in I ,1,3-trimethylcyclopen- 

tane. Activation energies for dehydrocyclisation 

differ significantly with KOH additions. KOH 

may promote active centres on Pt. Different types 

of active centre exist on Pt/C with different 

reactions occurring at each. 

Hydrogenation of Phenol in the Synthesis of 

Caprolactam 

G. D. LYUBARSKII and M. M. STRELETS, Khim. 

Promyshlennost’, 1967, 43, (7), 481-486 

A review of the processes using Ni or Pd cat- 

alysts (35 references). 

On the Negative Effect of Activated Carbon 

during the Hydrogenation of Unsaturated 

Compounds on Pt, Ni and Pd Catalysts 

D. v. SOKOL’SKII and B. 0. ZHUSUNBEKOV, Zh. 

fiz. Khim., 1967, 41, (59, 1213-1215 

Kinetic and potential curves were used to study 

the effect of mechanical mixtures of activated 

C with Pt- and Pd-black and Raney Ni catalysts 

on the H, adsorption capacity of unsaturated 

compounds, C,H,NO,, hept-r-ene and dimethyl- 

ethynylcarbinol during hydrogenation. The 


negative effect of the adsorbent is discussed and 

the rate of hydrogenation is found to be dependent 

on the nature of both the catalysts and the un- 

saturated compound. 

Relation between Shift of Catalyst Potential 

and Reaction Rate in Liquid-phase Hydro- 

genation Processes. IV. Correlation of 

Activities of Raney Ni, Pt- and Pd-black in 

Liquid-phase Hydrogenations 

v. A. DRUZ’ and L. N. SADCHIKOVA, Kinetika i 

Kataliz, 1967, 8, (3), 578-582 

Activity of Raney Ni, Pt- and Pd-black were 

compared in liquid-phase hydrogenations to 

increase product yields and surface area of each 

catalyst. Product yield depends on the specificity 

of the individual catalyst, 

Hydrogenation of Glucose on Raney Nickel 

Catalysts. I. 

F. B. BIKHANOV, D. v. SOKOL’SKII, N. I. POPOV, 

N. YA. MALKINA and A. M. KHISAMETDINOV, Ibid., 

620-624 

Pd or Ru additions to Raney Ni catalysts may 

increase the activity by 30% for the hydrogenation 

of glucose under pressure, with intense 

agitation. Optimum additions are O.I-O.~% Ru 

or s:,; Pd. Increased stability of the promoted 

catalysts was not apparent. 

Catalytic Activity of Reduced Noble Metal- 

Base Metal Mixed Oxides 

G. c. BOND and D. E. WEBSTER, Chem. Znd., 1967, 

(21, May 271,878-879 

Mixed oxides of Pt and either Fe, Co, Ni or Cu, 

and of Pd and either Co or Ni, when prepared by 

Adams’ method, have activities in excess of 

single oxides alone or of mechanically mixed 

oxides. This effect was shown in hydrogenations 

of C,H,NOz (60/, v/v in CH,OH), 2-methylhut-3-yn-2-01 

(7.5% v/v in CH,OH), and 

cyclohexene (17% v/v in CH,OH) at 30T, 

I atm H,. It is suggested that on reduction of a 

mixed base metal-noble metal oxide part of the 

base metal forms a solid solution with the noble 

metal. 

Hydrogenation of Dimethylethynylcarbinol 

on Palladium/Polyacrylonit.de Catalyst 

D. v. SOKOL’SKII, 0. A. TYURENKOVA and E. I. 

SELIVERSTOVA, Zh. fiz. Khim., 1967, 41, (6), 

1404-1410 

The rate of hydrogenation of dimethylethynylcarbinol 

on Pdipolyacrylonitrile, which is found 

to increase with increasing amount of catalyst and 

reactant, is faster in CH,OH and C,H,OH 

solutions than in aqueous solutions, but the reaction 

ceases as the catalyst surface becomes 

significantly charged with H,. The hydrogenation 

is more selective in neutral and alkaline solutions. 

An increase in acid or alkali concentration re-

duces the rate of reaction and the lateral dis- 

placement of the anode potential. 

Catalytic Hydrogenation of Butyronitrile 

H. GREENFIELD, Ind. Engng Chem., Product Res. 

DN., 19671 6, (2)~ 142-144 

Tests with Ni, Co, Pt, Pd, Rh, and Ru catalysts 

for the hydrogenation of butyronitrile to amines 

showed that Ni and Co appear to be best for the 

preparation of the primary amine butylamine, 

Rh best for production of secondary amine 

dibutylamine, and Pt and Pd best for production 

of tertiary amine tributylamine. Resistance to 

poisoning, the use of CH,OH or H,O as solvents 

and the effects of alkaline additives were studied. 

Kinetics of Electrodeposition and Catalytic 

Activity of Thin Films of Ruthenium 

M. PLEISCHMANN, J. KORYTA and H. R. THIRSK, 

Tram. Faraday SOL, 1967, 63, (5), 1261-1268 

Current-time curves, used to investigate the 

electrorecrystallisation of Ru from acid RuC1, 

solutions on to a Hg electrode, show that Ru is 

deposited in a single layer with a thickness of 

half the lattice repeat in the c, direction (2.136 A) 

of a h.c.p. lattice. The catalytic evolution of H, 

is confined to the edges of the growth centres of 

Ru and is similar to that exhibited for bulk Pt 

metals. 

The Catalytic Activities of Rhodium and 

Ruthenium in the Hydrogenolysis of Ethane. 

Influence of the Concentrations of Hydrogen 

and Ethane on the Reaction Rate 

G. K. STAROSTENKO, T. A. SLOVOKHOTOVA, A. A. 

BALANDIN and K. A. EL KHATTIB, Vest. MOSkOV. 

Univ., Ser. IZ, Khim., 1967, (3), 63-67 

5% Ru/SiO, has much greater specific activity 

than 5 % Rhl SiO for catalysing the hydrogenolysis 

of C,H,. Results of studies of the effects of the 

partial pressures of H, and C,H, on the reaction 

mechanism are tabulated. 

HOMOGENEOUS CATALYSIS 

Homogeneous Catalysis in the Reactions of 

Olefinic Substances. VIII. Isomerisation of 

1,5-Cyclooctadiene with Dichlorobis(tri- 

phenylphosphine)platinum(II) 

K. A. TAYIM and J. c. BAILAR,~. Am. Chem. SOL, 

19671 89, (141,3420-3424 

A study of the homogeneous isomerisation of 

1~5-cyclooaadiene by [PtCl,(PPh,)2] in the 

presence of the essential cocatalyst SnCl,.zH,O 

in N, or H, atmosphere is shown to proceed via 

a stepwise mechanism of hydride addition- 

abstraction with the formation of 5-coordinate 

hydridoplatinum-olefin complex. The role of 

SnC1,.2H20 is investigated and is found to 

function as the ligand SnC1,- which is a strong 

x-acceptor and prevents reduction of the Pt(I1). 


Homogeneous Hydrogenation of Methyl 

Linoleate Catalysed by Platinum-Tin Complexes 

E. N. FRANKEL, E. A. EMKEN, H. ITATANI and J. C. 

BAILAR,J. org. Chem., 1967, 32, (5), 147-1452 

The relative reactivity of catalysts in the homo- 

geneous hydrogenation of methyl linoleate is 

in the order H,PtCl,+ SnCl,>(PPh&s),PtCl,+ 

SnCl,>(PPh,P),PtClOH+SnCl,>SnCl,- 

(PPh,),PtOH. Rate curves for the reactions are 

given. Conjugated dienetrienes in trans, trans 

configuration are the major product except for 

H,PtCl, and SnCl, which gives trans-dienes. 

Butadiene from Vinyl Chloride. The Plati- 

num@) -catalysed Coupling of Vinyl Halides 

P. N. JONES, Ibid., 1667-1668 

The reductive coupling of vinyl chloride to give 

butadiene is catalysed by (C,H,),NSnCI, with 

CsF and PtCl, in aqueous DMF at 25°C. The 

effects of varying the reaction conditions and the 

SnPt ratio are evaluated. The formation of an 

isomer of [(SnC1,),PrC1,]2- and the role of CsF 

in the reaction are discussed. 

The Keaction of Rhodium Trichloride with 

D' ienes 

K. c. DEWHURST, J. org. Chem., 1967, 32, (9, 

1297-1 300 

RhC1, catalyses the addition to iso-C,H, of 

C,H,OH to give two isomeric ethers in a ratio 

which is temperature-dependent. On a larger 

scale, the air-stable complex [(C,H,), RhCl,],, is 

formed which gives an oil containing only hydrocarbons 

after hydrogenation with RhlC. A 

similar reaction occurs with butadiene but the 

oil obtained by hydrogenation of this Rh complex 

gave a C,, ether. 

Hydride Transfer Reactions Catalysed by 

Metal Complexes 

H. B. CHAR~MAN, J. Chem. Soc., B, phys. org., 1967, 

(6), 629-632 

Dehydrogenation of ;so-C,H,OH to (CH,),CO 

is catalysed homogeneously by RhCl, in the 

presence of LiCl and concentrated HCI. The 

mechanism is believed to be abstraction of a 

hydride ion from the ctC of iso-C,H,OH by 

RhC1, with subsequent transfer of this to the 

proton of HCl, resulting in evolution of H,, the 

rate of which decreases as Rh metal is precipitated. 

Organic Syntheses by Means of Noble 

Metal Compounds. Part 32. Selective Decarbonylation 

of q3-Unsaturated Aldehydes 

Using Rhodium Complexes 

J. TSUJI and K. omo, Tetrahedron Lett., 1967, 

(23)~2173-2176 

The decarbonylation of a-substituted cinnamal- 

dehydes in the presence of ClRh(PPh,), in 

C,H, or CH,CI, yields mainly cis-olefins. A 

dimeric complex is precipitated with sterically

hindered aldehydes at high temperatures unless 

organonitrile solvents are used. A 4 and 

aromatic aldehydes are readily decarbonylated 

at 20ooC or above, in the presence of the complex 

CIRh(CO)(PPh,), which is a more selective 

catalyst than PdC1,. 

Reactions and Catalytic Properties of Rho- 

dium Complexes in Solution 

B. R. JAMES, Cod. Chm. Rev., 1966, I, (4), 

505-524 

The catalysed synthesis of Rh(II1) complexes, 

the hydride, allylic and carbonyl complexes of 

Rh are reviewed, together with their reactivity 

as homogeneous catalysts in the hydrogenation 

and polymerisation of olefins and acetates and 

isomerisation of olefins. The solution chemistry 

of Rh is also discussed. (160 references.) 

Catalytic Properties of Platinum Group 

Metal Phthalocyanines 

B. D. BEREZIN and A. v. ~OsHcH~LoVA~Kinetika 

i 

Kataliz, 1967, 8, (3), 592-598 

0s and Ru phthalocyanines have high catalytic 

activity but other Pt metal phthalocyanines are 

inactive. (HSO,),OsPc is more active than 

(HSOJRuPc. Both are more active than Fe 

phthalocyanine. The effects of NaF, HCN and 

NH, on their reactions were studied. The kinetic 

equation, rate constants and activation energies 

of these catalysts were derived from quantitative 

studies and a mechanism for phthalocyanine 

catalysis is suggested. 

Catalytic Oxidation of Ethylene to Acetaldehyde 

in the Presence of Complexes of 

Ruthenium and Other Platinum Metals 

A. M. OSIPOV, K. I. MATVEEV and N. N. SHLTL'TS, 

Zh. ncorg. Khim., 1967, 12, (7), 1886-1892 

Studies of the oxidation of CZHI to CH,CHO in 

aqueous solutions of Pt metals and of Au showed 

that the addition of citric acid and some other 

oxycarbonic acids considerably increases the 

activity of Ru(II1) chloride complexes, and that in 

solutions containing Ru(II1) complexes, citric 

acid and Cu(I1) salts an intermediate complex 

of these three is formed. There are similarities 

between the mechanisms when using Pd(II), 

Ru(II1) or Pt(I1) complex catalysts. 

FUEL CELLS 

New Batteries Pack Hefty Doses of Energy 

Chem. EngW, 1967, 74, (14, July 3), 38 

Douglas Aircraft Co. has developed a rechargeable 

aerospace battery with Zn anode, Pt-plated Ni 

mesh cathode and novel separators. Energy 

density is IOO w.h/lb, shelf life is two years, and 

it operates at -40 to +300°F. A 5 A.h model 

has been cycled 2500 times without loss of 

capacity. The company has two patented methods 

for electrode production. 


A Unifying Scheme for the Electrochenlical 

Oxidation of Carbonaceous Fuels on Plati- 

num in Sulphuric Acid 

J. A. SHROPSHIRE, Electrochim. Acra, 1967, 12, (3), 

253-258 

A two-site generalised scheme is proposed for the 

adsorption and oxidation on Pt in aqueous 

H,SO, of the carbonaceous fuels, here represented 

by C,H,,, HCHO and CLHI. The oscillatory 

potential phenomena, observed during oxidation, 

are also explained on the basis of a two-site 

surface. 

Fuel Cell Oxidation of Hydrogen on Movable, 

Partially Submerged Platinum Anodes 

H. J. DAVITT and L. F. ALBRIGHT,J. Electrochem. 

SOL., 1967, 114, (6), 531-535 

Potentiostatic studies of two flat Pt anodes 

partially immersed in I N H,SO, at 3ooC, I 

atm showed that the electrochemical oxidation of 

H, is affected by meniscus formation, the elec- 

trolyte film formed on the exposed parts of the 

anodes, the surface roughness, and H, adsorption 

by exposed Pt. 

CHEMICAL TECHNOLOGY 

Considerations and Experiments for a 

Critical Evaluation of the Platinised Titan- 

ium Anode 

E. ZIRNGIEBL, Chem.-leg.-Tech., 1967, 39, (IZ), 

752-756 

Electrochemical comparisons of platinised Ti and 

graphite electrodes show that C1, has lower 

potential on the former and that the anode shape 

and cell characteristics are also important. Amor- 

tisation of a cell with platinised Ti anodes is 

quicker because of the reduced potential. 

The Kinetics of Metallic Activation Sin- 

tering of Tungsten 

I. J. Tom and N. A. LOCKINGTON, J. less-common 

Metals, 1967, 12, (9, 353-365 

Small amounts of Pd or Ni powerfully activate 

the sintering to high density of W and W-2% 

Tho, when introduced as halide salt solution for 

impregnation followed by reduction to metal. 

Optimum amounts, representing monoatomic 

layer were 0.317 wt.7; Pd and 0.130 wt."/:, Ni for 

3.3~ 

W particles. 

GLASS TECHNOLOGY 

Preparation of Optical Quality Glass in 

Small Batches 

A. D. PEARSON, J. R. FISHER and W. R. NORTHOVER, 

J. Am. Cerarn. SOL., 1967~50, (4), 219-220 

A method is described for the preparation of 

small batches of calcium lithium borate and borosilicate 

glass free of bubbles, inclusions and 

striations using a Pt crucible and strirrer.

TEMPERATURE 

MEASURXMEYT 

Two-Point Comparison 

E. W. JONES, Instrum. Control Syst., 1967, 40, 

(I), 115-118 

A two-point method for testing and calibration 

of Pt resistance thermometers gives accuracy of 

--0.015"C at -1oo"C and -0.006"C at 500°C 

on the International Practical Temperature Scale. 

NEW PATENTS 

METALS AND ALLOYS 

Heat Treatment of Platinum-Cobalt Magnets 

INTERNATIONAL NICKEL LTD. 

Britzsh Patent 1,067,054 

Remarkable magnetic properties can be pro- 

duced in pure alloys containing r9.8-31.2% Co 

by subjecting them to a disordering treatment at a 

temperature above 900°C for 30 min to I h, 

cooling to 630-75o'C at a rate of 50-150"C/min, 

cooling to room temperature, ageing at 630700°C 

for 5 min - 2 h and then quenching to room 

temperature. 

Tungsten-Ruthenium Alloy 

US. ATOMIC ENERGY COMMISSION 

British Patent 1,070,114 

The high temperature strength of W can be 

improved by adding 1.1-120,~ Ru (based on the 

weight of the alloy). A preferred composition is 

1.1 wt.O: Ru and 98.97, W. 

Alloys for Strain-Gauge Elements 

KABUSHIKI KAISHA HITACHI SEISAKUSHO 

U.S. Patents 3,305,8159 

In strain gauges the strain element consists of a 

binary alloy of 0s with 90-99'; Pt (815)~ a 

ternary alloy of 20-60 at.:; Pt, 20-60 at.:/, Pd 

and 5-30 at.% Ir (816) and a ternary alloy of 

15-80 at.16 Pt, 15-80 at.o/: Pd and 2-15 at.% Mo. 

Hydrogen Diffusion Tubes 

JOHNSON, MATTHEY 82 CO. LTD. 

US. Patent 3,312,043 

A closing plug for sealing the opcn end of Pd or 

Pd-Ag alloy H, diffusion tubes consists of 

material with approximately the same coefficient 

of thermal expansion and dimensioned to fit 

tightly with a projecting, threaded spigot of 

smaller diameter than the tube and used to form a 

means for attachment of or for stabilising an 

internal support for the tube. This corresponds 

to British Patent 1,009,326. 


A Precision PtRh-Pt Thermocouple for 

Research and Industry 

M. BEDUHN and w. HEYNE, Feinger. Tech., 1967, 

16, (6), 257-260 

Three East German research institutes have 

developed the "Model DAMW' Pt:Iooo Rh-Pt 

thermocouple instrument, which is suitable for 

both industrial and laboratory uses. Its con- 

struction, characteristics and calibration are 

described. 

ELECTROCHEMISTRY 

Electrode Boiler 

IMPERIAL METAL INDUSTRIES (KYNOCH) LTD. 


An electrode for an electrode boiler, e.g. for 

boiling H,O, has the parts immersed in the 

electrolyte (at least) made of Ti or its alloys coated 

with Ir, Rh, Ir-Pt, Rh-Pt or Ir-Rh-Pt. 

Production of Platinum and Palladium 

Oxides 

JOHNSON, MATTHEY & CO. LTD. 

French Patent 1,458,185 

Oxidation of these metals is achieved by electro- 

lysis of a Pt or Pd anode in a bath containing 

molten NaNO, and an alkali metal halide. This 

corresponds to Belgian Patent 664,526. 

ELECTRODEPOSITION AND 

SURFACE COATINGS 

Coating Titanium Surfaces 

SOCIETE D'ELECTRO-CHIMIE DES ACIERIES 

ELECTRIQUES D'UGINE British Patent 1,069,005 

Process for coating Ti or its alloys with a metal 

of the Pt group. The metal to be coated is acid 

pickled and the Pt group metal deposited and 

then heated at 150-3oo@C. 

Applying Designs to Metallic Bases 

JOHNSON MATTHEY & CO. LTD. 


A decorating composition for application to a 

noble metal base consists of a metallising paste 

containing Au, Ag, Pt, Pd or alloys thereof. 

Palladium Plating 


German Patent 1,239,159 

An aqueous neutral or alkaline Pd bath contains 

a Pd compound, e.g. (PdNH,),(NO,),, and a 

NHI salt of a weak acid which does not form an

insoluble compound with the Pd compound, e.g. 

ammonium tartrate. 

BRAZING 

Brazing Alloys for Tungsten and 

Molybdenum 

U.S. ATOMIC ENERGY COMMISSION 

US, Patent 3,312,539 

These metals and their alloys are brazed using 

alloys of 42-95 wt.O/, Mo, 5-44 wt.3; Rh and up 

to 45 wt.:b Re. 

Solder for Soldering Electrovacuum 

Instruments 

B. E. KOVALEVSKII et al. 

U.S.S.R. Patent 186,836 

A solder of lower melting point which has 

increased strength and plasticity of the soldered 

joints has composition 8-12 wt?; Ge, 2-12 wtx 

Pd, balance Cu. 

CATALYSIS 

Production of Saturated Aldehydes 

WACKER-CHEMIE G.m.b.H. 


The partial hydrogenation of olefinically sub- 

stituted aliphatic aldehydes at 7G-I4O0c is 

catalysed by a mixture of metallic Pd and one or 

more of Cu, Ni and Co. Au or Ag may also be 

present. 

Silanes, their Quaternary Salts and Polymers 

DOW CORNING CORP. British Patent 1,066,346 

Haloether silanes are obtained by the Pt-catalysed 

co-reduction of a silane and a hydrocarbon ether. 

Production of Araliphatic Dicarbinols 

SCHOLVEN-CHEMIE A.G. British Patent 1,066,401 

The corresponding hydrocarbons are oxidised to 

hydroperoxides and then reduced to dicarbinols 

using H, and Pt/A1,0,. 

Carbonylation of Olefinically Unsaturated 

Compounds 

BADISCHE ANILIN-& SODA-FABRIK A.G. 


Carbonylation is catalysed by L,PdX,, where 

L is an organic phosphine or phosphite, NH,, 

an amine, a nitrile or an unsaturated hydrocarbon, 

X is an anion, m is 1-4, n is 1-2 and n+m is 2-6, 

e.g. Pd(PPh,),CI,. 

Vinyl Acetate Production 

IMPERIAL CHEMICAL INDUSTRIES LTD. 


The catalyst for the reaction of CeHa with 

CH,COOH consists of a redox system and a Pd 

salt other than the fluoride. 


Regeneration and Reactivation of Supported 

Platinum Group Catalysts 

SHELL INTERNATIONALE RESEARCH MIJ. N.V. 


Reforming catalysts are regenerated by treatment 

with C1, or a compound which liberates C1, on 

heating, followed by burning in a gas containing 

0, to remove C. The catalyst is then maintained 

at a temperature higher than burning temperature 

in a gas of higher O2 content. 

Hydrocracking Process 

ESSO RESEARCH & ENGINEERING CO. 


A crystalline alumino-silicate zeolite composited 

with a Pt group metal is used for hydrocracking 

of hydrocarbons. 

Production of Finely Divided Catalyst 

Layers on the Pore-free Surfaces of Hydro- 

gen-absorbing Metallic Bodies 

VARTA A.G. British Patent 1,071,503 

A metaliic body is coated on one side with a 

catalyst layer and subjected to H, pressure, whilst 

on the other side (e.g. in a tube) a solution of the 

metal to be used for hydrogenation (e.g. Pd 

(NO,),) is precipitated by diffusion of H, and 

reduction. 

Composite Catalysts 

OFFICE NATIONAL INDUSTRIEL DE L'AZOTE 


A catalyst comprising 0.1-2.0~6 Pt, 8-50?; Ni 

and/or Co and an A1,0, or MgO support. It is 

used in the methanation of CO by H, and in the 

reforming of hydrocarbons. 

Hydrocarbon Conversion Process 

TEXACO DEVELOPMENT COKE'. 


Mixtures of hydrocarbons (pentone, hexone, etc.) 

may be converted to highly branched hydrocarbon 

products by using a chloride-activited Pt/Al,O, 

catalyst. 

Preparation of Aryl Thiols 

UNITED STATES RUBBER CO. 


PtS, is used as a catalyst for conversion of aryl 

sulphinic acids to aryl thiols by hydrogenation. 

This obviates the use of H,S and S which are 

needed with prior art processes using base metal 

sulphides . 

Preparing Catalysts 



A highly active catalyst is made by contacting a 

support with a salt solution of a catalytic metal, 

reducing the metal ions and subsequently remov- 

ing the support to leave a finely divided metal.

Thus Pt metals, Ag and Au can be deposited 

singly or in mixtures on CaCO, which is then 

removed. 

Dehydrogenation of Cyclo-octene 

U.S. RUBBER CO. U.S. Patent 3,305,593 

1,5-Cyclo-octadiene is produced by heating 

cyclo-octene and a Rh salt, e.g. RhCl,, in CH,OH, 

at 50-15o~C. 

Hydro dealkylation Catalyst 

UNIVERSAL OIL PRODUCTS CO. 

U.S. Patent 3,306,944 

The demethylation of alkyl aromatic hydrocarbons 

with Rh is catalysed by Rh deposited 

on an alkali metal-promoted metal oxide support, 

e.g. Li/Al,O,. 

Selective Hydrogenation of Hydrocarbons 

MOBIL OIL CORP. U.S. Patent 3,309,307 

Dienes are selectively hydrogenated in the pre- 

sence of olefines by using a Pd catalyst in the 

presence of either CS, or H,S below the de- 

sulphurisation temperature. 

Catalytic Hydrogenation of Paraffin 

Hydrocarbons 

UNIVERSAL OIL PRODUCTS CO. 

U.S. Patent 3,310,599 

A new composite catalyst, e.g. for producing 

iso-C,H, from iso-CqH,Oy 0.01-1.59, Al,O:,/Li, 

0.05-5% Group VIII metal and sufficient Te, 

Se or their compounds to give full cracking and 

isomerisation of the Group VIII metal. Pt and 

Pd are the preferred noble metals. 

Catalyst for Combining Hydrogen and 

Oxygen in Thorium Slurries 

US. ATOMIC ENERGY COMMISSION 

U.S. Patent 3,312,526 

A catalyst for reversing the radiolytic decomposi- 

tion of H,O in Tho, slurries is produced by heating 

an aqueous Tho, sol and platinic acid in a Th:Pt 

ratio of 2-3:r until a floculated suspension is 

formed. The suspended solids of platinised Tho, 

are recovered and added to Thoz slurries. 

Preparation of Butyrolactone 

PETRO-TEX CORP. U.S. Patent 3,312,718 

Succinic anhydride is hydrogenated to butyro- 

lactone in the presence of a suitable catalyst, e.g. a 

Pt metal, and silicotungstic acid at 200-300rC and 

at above 500 psig. 

Mono-oxonation Products of Cyclic Dimers 

and Trimers o€ Butadiene 

CHEMISCHE WERKE HULS A.G. 

U.S. Patent 3,312,742 

These butadiene-1,3 dimers and trimers are 

reacted with CO and H, in the presence of a 

catalyst mixture consisting of (a) Co carbonyls or 

salts of fatty acids, I'd halides or finely divided 


Pd and (b) a Cu chromite, Pt or Ag/Zn/Cr oxide 

to introduce a formyl group on a double bond. 

Production of 4-Halobutene-1 

E.I. DU PONT DE NEMOURS & CO. 

U.S. Patent 3,3r2,747 

Commercially valuable 4-chloro- and 4-bromo- 

butene-1 are produced by dehydrohalogenation 

of 1,3-dihalobutane at 200-385~C in the presence 

of Pd/Al,O,, Rh/Al,O,, ZnO or activated A1,0,. 

Platinum Double Bond Addition Catalyst 

GENERAL ELECTRIC CO. (NEW YORK) 

U.S. Patent 3,313,773 

The addition of a Si compound, having at least 

one atom of H attached to the Si atom, to a 

C-C unsaturated bond is catalysed by trimethyl 

platinum iodide or diplatinun hexamethyl. 

Hydrocracking Process 


U.S. Patent 3,318,802 

The activity of a crystalline SO,-Al,O, zeolite 

containing a Pt group metal is increased by 

introducing a halogen containing compound into 

the hydrocracking zone. 

Production of Metallic Oxides 


FTench Patent 1,458,185 

Oxides of Pt, Pd or mixtures of Pt andjor Pd 

with other metals are produced by electrolysing 

a molten bath of an alkali metal nitrate and 

chloride with anodes of the requisite metals. 

Oxide Catalysts for Chemical Reactions 



The catalyst is a homogeneous and intimate 

mixture, not merely a physical mixture, of 

zo-goo:, PtO, and 1o-80% RuO, by weight. 

Chemical Reaction Catalyst 

G. WILKINSON 

French Patent 1,459,643 Italian Patent 748,928 

A catalyst for hydrogenation, hydroformylation 

and carbonylation consists of a platinum metal 

halide or pseudohalide complexed with an 

organic isocyanate or a Group VB or VIB 

compound, e.g. (Ph,P),RhCl. This corresponds 

to Canadian Patent 745,663. 

Catalyst Production 


Dutch Appln. 66.17,004 

A general purpose chemical reaction catalyst is 

an intimate homogeneous mixture of a Pt metal 

oxide and a baser metal oxide, preferably in a 

ratio of 3:r or higher. The base metal may be 

Fe, Co, Ni, Cu, etc., e.g. a mixture of Ni and Pt 

oxides. The mixture must not be a simple 

physical mixture.

Ole& Isomerisation 


Italian Patent 743,469 

An improved catalyst especially for olefine 

isomerisation consists of a salt such as RhCl, or 

PdCl, dissolved in a virtually non-volatile 

hydroxylic compound, e.g. propylene glycol, 

optionally dissolved on an inert porous support. 

This corresponds to French Patent 1,445,176. 

FUEL CELLS 

Fuel Cells 

TOKYO SHIBAURA ELECTRIC CO. LTD. 

Brztish Patent 1,074,561 

A H, electrode consists of a non-porous Pd or 

Pd alloy plate which is covered with Pd black on 

the surface exposed to H,, and with black mixture 

of Pd and Pt on the other surface. 

Electrodes 

RODERT BOSCH G.m.b.H. British Patent 1,074,862 

Porous sintered electrodes for fuel cells use Ni as 

frame metal, and Pt group metal or its Ni alloy 

as skeleton catalyst in which up to 20"; Ti, V, 

Cr, Co, Mo, Ru or Ta is added. 

Hydrogen Fuel Cell Structure 

UNION CARBIDE CORP. U.S. Patent 3,307,977 

A heavy metal salt of at least one of Fe, Co, Ni, 

Mn, Cr, Cu, Ag, Au, V, Ti, Th, U and rare earth 

metals is used with an A1 salt to coat a layer of 

spinel on a porous body (e.g. C). A Pt salt is then 

used to deposit a catalytic layer. 

Fuel Cell Electrode 

AIR PRODUCTS & CHEMICALS INC. and NORTHERN 

NATURAL GAS CO. U.S. Patent 3,309,231 

It has been found that when Pt is used with a 

Group IB or VIII noble metal in certain proportions, 

the noble metal acts synergistically to 

improve the activity of the Pt metal catalyst. 

Activation of Electrodes Containing 

Platinum or Palladium 

UNION OIL CO. OF CALIFORNIA 

U.S. Patent 3,311,508 

Pt or Pd bonded to a fuel cell electrode is activated 

by exposure to a H, atmosphere at room temperature. 

After activation the electrode must be 

exposed to an inert atmosphere to remove H, 

traces before use in the presence of 0,. 

CHEMICAL TECHNOLOGY 

Process for Bonding Two Temperatureresistant 

Members 

SOCIETE NATIONALE D'ETUDE ET DE CONSTRUCTION 

DE MOTEURS D'AVIATION British Patent 1,071,179 

A bonding layer is interposed between the sur- 

faces of the two members at least one of which is 


made of graphite, This layer is a refractory 

material comprising the elements W, Mo, Zr, 

Hf, Ta, Ti and Ni; either singly or as mixtures 

and one or more of the Pt group metals. 

Production of Pure Hydrogen 

J. F. MAHLER APPARARATE- 82 OFENBAU K.G. 

German Patent 1,238,884 

NH, is decomposed, in the absence of further 

catalysts, on a hot membrane containing Pd 

which allows the nascent H, to pass through. 

ELECTRICAL AND 

ELECTRONIC ENGINEERING 

Semiconductor Devices 

MULLARD LTD. British Patent 1,074,284 

A semiconductor device is made by alloying Bi 

and Pt to a semiconductor body consisting of at 

least two components, none of which is Bi. The 

amount of Pt is up to IOO; of the alloy. 

Electrical Resistance Element 

CTS COW. US. Patent 3,304,199 

Resistance elements are produced by applying to 

a non-conducting substrate a mixture of 2-70 

wt."; of a finely divided metal oxide selected from 

RuO, and IrO, and 98-30°& powdered glass frit. 

Impedance Element with Alloy Connector 

NYTRONICS INC. U.S. Patent 3,310,718 

Strong stable leads to miniaturised impedance 

components are produced using connectors (such 

as wire) made from wrought Ag-Pd alloy, parti- 

cularly alloys with 3-20?; Pd. 

Iridium Tip Electrode 

CHAMPION SPARK PLUG CO. U.S. Patent 3,315,113 

A tip electrode, especially for a sparking plug, is 

made from an Ir wire on which an outwardly 

extending shoulder is formed by melting the 

centre of the length of wire and pushing the ends 

inwards. This avoids mechanical working in 

which the metal is embrittled. 

Platinum Electrical Contacts 

INTERNATIONAL BUSINESS MACHINES CORP. 


Contacts with ohmic properties stable at high 

temperatures are mixtures of 91-93 wt.O/, of a 

Pt group metal and 7-9 wt."; of C. The Pt 

group metal is suitably Pt. 

Ruthenium in a Glass Conductor 

AIR REDUCTION CO. INC. 

French Patent I ,463,749 

A new form of electrical resistance consists of a 

mixture of T1 oxide and RuO, intimately dispersed 

in a vitreous matrix. Preferably the 

RuO, is 0.05-80°/, of the mixture. Au, Pt or 

Pd may also be present.

Puge 

Acres, G. J. K. 

Albright, L. F. 

38, 86 

158 

Aldag, A. 35 

Aldred, A. T. 1 I3 

Alimov, Sh. A. 32 

Allam, M. I. 1 I6 

Almar-Naess, A. 39 

Anderson, J. R. 36 

Andresen, A. F. 71 

Andrews, J. M. 92 

Antler, M. 115 

Apel'baum, L. 0. 36 

Arajs, S. 32 

Arkharov, V. I. 11 3 

Armstrong, P. E. 33 

Arons, R. R. 72 

Aso, T. I52 

Attardo, M. J. 31 

Avery, N. R. 36 

Bailar, J. C. 118, 157 

Baird, M. C. 153 

Balandin, A. A. 77 

Banus, M. n. 33 

Bardysbev, I. I. 38 

Barinov, N. S. 77 

Barland, P. 34 

Barron, Y. 35 

Bartlett, R. W. 150 

Beduhn, M. 159 

Belmahi, 0. 31 

Bennett, R. P. 118 

Berezin, B. D. 158 

Berry, R. J. 150 

Bikhanov, F. B. I56 

Binder, H. 57, 78, 115 

Birch, A. J. 77 

Blair, J. 100 

Blanchard, A. 71 

Blasiak, E. 1 16, 154 

Blume, H. 35 

Blumenthal, J. L. 53 

Bolotin, G. A. 112 

Bond, G. C. 38,75, 156 

Booth, G. H. 154 

Boronin, V. S. 117 

Boudart, M. 35 

Bouman, J. 72 

Bradford, C. W. 104 

Bradley, I). 39 

Breiter, M. W. 115 

Brinkman, W. F. 152 

BrissoMeau, P. 71 

Brodersen, K. 33 

Brodowskv. H. 3 1. 11 3 

Bronger, W. 71 

Brown, C. A. 74 

Brown, D. W. 49 

Brown, H. C. 74 

Brown, H. L. 33 

Brusir, V. 

154 

Bubyrev, A. N. 151 

Bucher, E. 152 

Buehl, W. M. 79 

Bufferd, A. S. 112 

Bums, G. W. 10 

Burwell, R. L. 35 

Butler. C. A. 115 

Butt, J. B. 

34 

Cadenhead, D. A. 

Cairns, E. J. 

Candlin, J. P. 

Cannon, W. A. 

Carlson, C. W. 

Carpenter, R. W. 

AUTHOR INDEX TO VOLUME 

76 

78 

73 

78 

116 

1 50 

Page 

Carson, A. W. 151 

Casale, M. E. A. I 26 

Cashmore, P. 39 

Chaikin, S. W. 56 

Chalk, A. J. 37 

Charman, H. B. 37,157 

Chasse, C. J. 120 

Chesswass, M. 74 

&ek, A. 70 

Cleare, M. J. 148 

Cockayne, B. 74 

Coles, B. R. 109 

Collman, J. P. 73, 114 

Colyer, J. 0. 34 

Connolly, J. F. 115 

Connor, H. 2, 60 

Conti, F. 73 

Cooper, A. W. 154 

Cornet, D. 76 

Cotton, J. B. 50 

Cowan, J. H. 79 

Cramer, R. 37, I19 

Cross, R. J. 1 I4 

Cucka, P. 32 

Cusumano, J. A. 35 

Damjanovic, A. 34, 154 

Dangel, P. N. I52 

Darby, J. B. 72 

Darling, A. S. 94, 138 

Davitt, H. J. 158 

Dembenski, G. W. 35 

De Mourgues, L. 117 

Dent, W. U. 116 

Dewhurst. K. C. 157 

Dey, A. 34 

Dietrich, H. 129 

Dixon, M. 70 

Donati. M. 73 

Doniach, S. 113 

Donnelly, R. G. 140 

Doronicheva, N. 1. 3 1 

Downey, J. W. 72 

Drnz', V. A. 35, 156 

Druzhinin, A. V. 79 

Dubien, J. 117 

Dunnigan, D. A. 77 

Dwight, A. E. 72 

Edshammar, L.-E. 152 

Emken, E. A. 157 

Emmett, P. H. 74 

Entwistle. A. G. 39 

Eremenko, V. N. 32 

Ettmayer, P. 1 I4 

Evans, E. W. 151 

Fakidov, I. G. 113 

Falbe, J. 119 

Fasman, A. B. 36, 37,74 

Fegan, L. V. 39 

Ferents, V. Ya 112 

Filonenko, A. P. 75 

Fine. T. E. 71 

Firth, J. G. 36,76 

Fishcr, A. H. 116 

Fisher. J. R. 158 

Fisher; L. P. 119 

Fishman, J. H. 154 

Flanagan, T. B. 71, 151 

Flanagan, W. F. 15 1 

Flannery, R. J. 115 

Fleischer, E. 114 

Fleischmann, M. 157 

Flid, R. M. 118 


Puge 

Frankel, E. N. 157 

Freifelder, M. 77 

Fullenwider, M. A. 34 

H&e,"'W. 

Hightower, J. W. 

Hirsch. H. 

Hitzroi, H. W. 

Hoare, F. E. 

Hoare. J. P. 

Hoenig, S. A. 

Hofer, E. M. 

Holland. H. B. 

Holliste;, R. G. 

Holzmann, H. 

Hopff, H. 

Huppes, N. 

Husemann, 13. 

lgnatov, D. V. 

Tles, G. S. 

Imamura, S. 

lngraham, T. R. 

Ioffe. I. I. 

Isabekov,. A. 

Itatani, H. 

Ivashentsev, Ya. 1.- 

70 

33 

116 

32 

76 

94 

74 

117 

119 

31 

I50 

I26 

119 

34 

156 

36 

118 

James, B. R. 78, 158 

James, W. G. 1 I6 

Jardine, F. €3. 119 

Jasorska-Galas, Z. 35 

Jeitner, 0. I I6 

Johnson. D. A. 37 

Jones, 12. W. I59 

Jones, F. N. 157 

Jones. J. M. 140 

Joshi,' K. K. 73 

11 

Page 

Kahrig, E. 78 

Karakhanov, R. A. 75 

Karev, V. N. 74 

Katsnel'son, A. A. 32 

Kawasaki, K. 112 

Kazakora, V. 1. 114 

Keim, W. 153 

Kemp, A. L. W. 78 

Kerr, W. B. 119 

Ketley, A. D. 119 

Khomenko, A. A. 36 

Khorov, Yu. M. 155 

Khrushch, A. P. 77 

Kin, M. J. 112, 151 

Kirillova, M. M. 112 

Kitchingman, W. J. 112 

Gallaher, J. S. 10 

Galligan, J. M. 31 

Gamboa, J. M. 74 

Gardam, G. E. 70 

Gault, F. G. 76, 117 

Gerberich, H. R. I18 

Gibb. J. G. 100 

Giessen, B. C. 152 

Gileadi, E. 34 

Gingerich, K. A. 71 

Ginzburg, S. I. 73 

Glemser, 0. 33 

Goldberg, A. 1 I6 Kjekshus, A. 71 

Golodov, V. A. 37 Kleiu, A. 154 

Gonikberg, M. G. 75 Klimova, N. V. 156 

Greaves, E. 0. 33 Klyucharev, A. P. 74 

Green, M. 37 Koch, D. F. A. 153 

Greenfield, H. 157 Kohlhdas, R. 152 

Grinberg, A. A. 114 Kohliug, A. 57, 78, 1 I5 

Gullman, L. 0. 32 Kohll, C. F. 118 

Gurevich, M. A. 3 I Kokes, R. J. 36 

Kolbin, N. I. 152 

Konig, K. 

116 

Hall, J. A. 39 Koros, R. M. 117 

Hall, W. K. 118 Koryta, J. 157 

Halpern, J. 77,78 Kos, J. F. 

120 

Hama, M. 76 Kouvel, J. S. 152 

Hanky, J. B. 70 Kral, H. 

76 

Hansen, R. S. 32 Kralina. A. A. 113 

Hardy, W. B. 118 Kravtsov, V. I. 34 

Harris, I. R. 72 Krylova, I. V. 75 

Harrison, D. P. 155 Kubicki, J. 154 

Harrod, J. F. 37, 78 Kubota, M. 73 

Haszeldine, R. N. 37 Kubn, A. T. 153 

Hayfield, P. C. S. 115 Kupenko, 0. G. 75 

Hevdinz. R. D. 114 Kutsar, A. R. 113 

159 Kutyukov, G. G. 37 

74 Kuzembaev, K. K. 38 

113 Kuz'min, V. M. 150 

39 Kuznetsov, E. A. 150 

Iveronova, V. I. 

Iwamoto, K. 

Lakey, L. T. 

Lam, D. J. 

Lamarche, J. L. G. 

Landor. S. 

Lange, P. 

Lasko, W. R. 

Laubitz. M. J. 

Lavine,'M. C. 

Layton, A. J. 

Leder. F. 

119 

32 

120 

79 

78 

11s 

70 

33 

1 I4 

34 

Lee, J. B. 39 

Levitskii, I. I. 75 

Lewis, F. A. 99, 151 

Lindsey, R. V. 37 

Llopis, J. 74, 154 

Lockington, N. A. 158 

Lommel, J. M. 152 

Loshchilova, A. V. 158 

Lozinskii, M. G. 112 

Lozovoi, A. V. 76 

Idyou, H. B. 150 

Lyubarskii, G. D. 156 

McCormack, J. M. 71 

McDaoiel, C. L. 152 

McDonald, D. 18, 106 

Machmer, P. 153 

McKee, W. E. 147 

Maclean, A. F. 119 

McLean, M. 70 

Maeland, A. J. 113, 151

Page Pare Page 

Page 

Maire, G. 35, 117 Petrii, 0. A. li5 Sloboda, M. H. 74 Van Laer, P. 149 

~ Maitlis. P. M. 33 Pickwick. K. M. 11 2 Slovokhotova, T. A. 157 Van Reuth, E. C. 31 

Markini T. I. 76 Piersma. B. J. 

Smirnova, E. B. 38 Van Stratum, A. J. A. 

Markov,'V. D. 37 Ponec, V. 75 Smith, C. P. 79 

15 __ 

Martyshkina, L. E. 11 7 Ponyatovskii, E. G. 1 13 Smith, G. V. 76 Vastine, F. D. 73 

Marvet. R. V. 115 Porzel. W. 116 Smith, J. M. 35 Vazquez, M. 154 

Masse,". G. 76 Potlova, G. A. 38 Sohn, R. L. 31 Vergnaud, J.-M. 156 

Mathis, B. 1 I4 Powell, A. R. 58 Sokolova, N. P. 77 Vlugter. .I. C. 116 

Matsuo, Y. 112 Powell, R. W. 70 Sokol'skaya, A. M. 38 vo& E. - 71 

Matveev, I(. I. 158 Pravoverov, N. L. Sokol'skii, D. V. 

Volodin, Yu. A. 79 

Mauret, P. 154 

113, 151 

36, 38, 76, 156 Von Hahn. E. A. 34 

Maymo, J. A. 35 Pregaglia, G. F. 73 Somorjai, G. A. 150 Von Philipsborn, H. 155 

Meibuhr, S. G. 33 Ptitsyn, B. V. 114 Spector, N. L. 38 Von Schnering, H. G. 33 

Melmed, A. J. 150 

Stark, D. 151 Voznesenskaya, I. I. 

Merck. M. 31 

Starostenko, G. K. 157 

35, 75 

Mimeault, V. J. 32 Radyushkina, K. A. 115 Stautzenberger, L. 119 

Mitchell, W. I. 70 Rase, H. G. 155 Stern, E. W. 38 

Mitrofanova. A. N. 117 Raub, E. 70 Strassmair, H. 151 

Walker, K. A. M. 

I7 77 

Moiseev. I. I. 77 Raynor, G. V. 72 Strelets, M. M. 156 

Wang, F. E. 

114 

Montgomery, K. M. 154 Rennard. R. J. 36 Strel'nikova, Zh. V. 117 

Warne, M. A. 

115 

Moss, R. L. 141 Rey-Coquais, B. 156 Sugita, T. 112 

Warner, T. B. 

73 

Mozzhukina, V. M. 36,75 Rhee, S. K. 112 Swoap, J. R. 76 

Waterstrat. R. M. 

31 

Musheuko, D. V. 77 Ritchie, A. W. 117 Syutkina, V. I. 32 Webb, G. 

46 

Myers, J. R. 71 Rodina, A. A, 31 Szkibik, C. 35 Webster, D. E. 

156 

Mykura, H. 70 Roesky, H. W. 33 

Weiss. W. D. 

152 

Myles, K. M. 32, 72 Rojkind, M. 34 

Weissinan, E. Y. 

I53 153 

Roschel, E. 70 Taueeva. V. G. 74 Wells, P. B. 

38,75 38 I, 75 

Roth, H. A. 115 Tankins,' E. S. 31 Wiese, Wiese. U. 

114 

Nagasawa, A. 112 Rotinyan, A. L. 33 Tarasevich, M. R. 11 5 Wikans, Wilr J. 114 

Neuse, E. W. 33 Rudman, P. S. 72 Tavim. H. A. 157 Wilke, G. 

72 

Nicholson, M. E. 71 Rummery, T. E. 114 Thicker, R. 33 Wilkinson, G. 1 

19, 153 I53 ~ 

Nishimura, S. 76 Rusling, R. Y. 120 Tharby, R. 34 Wilson. R. G. 72 

Nixon, A. C. 117 Russell, A, D. 111 Thomson, S. J. 46 Wohlfarth, E. P. 

113 

Nogi, T. 38 Rytvin, E. I, 150 Timonova, R. I. 33, 114 Wolf, E. D. 

72 

Nowak, E. J. 117 

Tokina, L. A. 77 Wroblowa, Wroblowa. H. 153 

Nyholm, R. S. 114 

Toth, I. J. 158 Wnyszcz, Wnyszcz,'J. J. 

35 

Sadasivan, N. 114 TouSek, J. 153 Wuhl, H. 

72 

Sadchikova, L. N. 156 Toy, M. S. 78 Wynveen, R. A. 

Odaira, Y. 37 

154 

Oehler, E. 71 Samoilov, V. M. 152 Treger, Ya. A. 118 

Ogren, J. R. 53 

Schafer, H. 114 Tribunskaya, L. A. 113 

Ohno, K. 38,39, 157 Schuabel, K. H. 156 Tsuji, J. 

Yakovleva. E. S. 32 

Oishi. T. 37 Schueider, S. J. 152 38. 39. 77. 119. 157 Yaniv, A. E. 154 

Okamoto, H. 152 Schott, H. 72 Turk, R.'R.' ' ' I47 Yarish, M. 154 

Osipov, A. M. 158 Sellberg, B. 72 Tye, R. P. 70 Yoshida. K. 155 

Ostrovidov, E. A. 33 

Selman, G. L. 132 Tyrrell, C. J. 115 Yuz'ko,'M. I. 73 

Otaki, T. 155 Shashkov, A. S. 36 Tyurenkova, 0. A. 

Owen, E. A. 151 Shaw, B. 93 

36,76, 156 

Shropshire, J. A. 158 

Zalm, P. 15 

Shtepa, T. D. 32 

Zavadskii, E. A. 113 

Panchenkov, G. M. 155 Shnikin, N. I. 35,75 Utegulov, N. I. 35 Zelenskii, M. I. 34 

Panetta, C. A. 37 Sikora, H. 11 6, 154 

Zeliger, H. I. 119 

Pearlman, W. M. 11 6 Simonite, Yu. P. 75 

Zhusnnbekov, B. 0. 156 

Pearson, A. D. 158 Simons, J. W. 71 Van der Meer, J. P. 70 Zirngiebl, E. 158 

Pestrikov, S. V. 77 Sipes, W. A. 31 Van Heldeu, R. 118 Zwilksy, K. M. 112 

SUBJECT INDEX TO VOLUME 11 

a=abstract Page 

Anodic Corrosion, of Ru, a 74 

Beta 750, electrodeposit thickness gauge 13 

Brazing, graphite, with Pd alloy 140 

review of alloys for, a 

74 

Catalysis, ,homogeneous and heterogeneous, 

symposia on 16 

homogeneous. Oxford Inorganic Discussion 

on 30 

homogeneous, transition metal complexes in, a 77 

mechanism of heterogeneous, a 35 

Platforming, mathematical description of, a 155 

Pt metals in, 2nd Canadian Symposium on 146 

radiochemical study of 46 

trickle column reactors for 86 

Catalysts, for HNO, production, review of, a 

preparation of, by reduction of PtIV, a 117 

supported, electron microscopy of 141 


74 

.~ 

Catalysts (Confd.) Page 

Adams', activity of, a 156 

Bromopalladate ions, catalytic activity of, a 37 

Iridium, C,H,, oxidation of, a 153 

h/A1208, deuteration of CIH6 on, a 

hydrogenation of C,H, on, a 38 

NIIALO,, promoted with Pt and Pd, a 117 

Ni0, Pd-promoted, a 117 

NiO, Pt-promoted, a 117 

Nylon-Platinum, activity and selectivity of, a 155 

hydrogenation, of C,H, on, a 155 

Osmium, C,H,, oxidation of, a 153 

OsO,, regeneration of, in situ, a I19 

homogeneous air oxidation with, a 119 

0s phthalocyanine, activity of, a 158 

Palladium, acido complexes, activity of, a 37 

black, activity of, in liquid phase 

hydrogenation, a 156 

complexes, oxidation and reduction by 93 

complexes, oxidation of CaH, on, u 158 

75

Catalysts (Conrd.) Page Catalysts (Confd.) Page 

Complexes, isomerisation of deuterio 

Platinum, black, activity of, in liquid phase 

olefins on, a 37 hydrogenation, a 156 

complexes, Ph,As. hydrogenation of 

complexes, oxidation and reduction by 93 

soybean oil methyl ester on, a 118 

complexes, oxidation of C2H, on, a 158 

complexes, Ph,P, hydrogenation of 

complexes, Ph,As, PhaP, Ph,Sb, a 118 

soybean oil methyl ester on, a 118 

dehydrogenation of cyclohexane on, a 35 

disproportionation of cyclohexene 86 

electrodeposited, activity of, a 115 

C2H4. oxidation of, on, a 118, 153 

C2H,, oxidation of. on, a 153 

films, conversion of methyl propyl 

film, conversion of methyl propyl ketone 

ketone on, a 76 

on, a 76 

films hydrogenolysis and isomerisation 

film, H a-02 reaction on, a 75 

on, a 117 

gauze, manufacture of HNOI and HCN 60 

films, isomerisation on, a 36 

hydrogenation of benzyl alcohol on, a 76 

hydrogenation of butyronitrile on, a 157 

hydrogenation of butyronitrile on, a 157 

hydrogenation of rosin on, a 38 

hydrolysis of allyl chlorides, a 118 

hydrolysis of allyl chlorides, a 1 I8 

hydrogenolysis and isomerisation on, a 11 7 

isomerisation on, a 37 

isomerisation of hexanes on, a 

35 

membranes, decomposition on, n 36 

isomerisation on, a 36, 37 

mixed oxides, activity of, a 156 

losses in HNO, manufacture, a 154 

potential of, a 74 

mixed oxides, activity of, a I56 

synthesis of caprolactam, a 156 

oxidation of carbonaceous fuels on, a 158 

Palladium Acetate, reaction with vinyl 

potential of, a 74 

acetate, a 1 I8 

reforming, automation of, a 154 

PdCI,, carbonylation of carboxylate 

reforming, conversion of 

compounds, a 38 

bicyclonaphthenes on, a 1 I6 

cleavage of Si-Si bond, a 

118 

reforming, damage in use, a 35 

dimerisation of alkenes, a 

1 I9 

single crystal growth, of CdCr,Se,, a 155 

isomerisation of butenes, a 77 

S-modified 57 

oxidation of n-butylamine, a 77 

supported, conversion of methyl propyl 

production of vinyl acetate, a 118 

ketone on, a 76 

reactions with nucleophiles, a 37, 38 

suspension of, CO adsorption on, a 74 

synthesis of rr-allylic Pd complexes, a 119 PtC12, preparation of butadiene on, a 157 

PdC1,-CuCI,, production of vinyl acetate, a 118 PtCI2(PPh,),, isomerisation of I ,5-cyclo- 

Pd-Cu, hydrogenation of C,H, on, a 76 octadiene, a 157 

Palladium Cyanide, synthesis of olefinic 

Pt-Pb black, electrodeposited, activity of, a 1 15 

cyanides with, a 

37 Pt-Ni, CIH,, oxidation of, a 153 

Pd-Au, activity of, a 

154 Pt/Al20,, activation of, a 75 

C,H,, hydrogenation of, on, a 76 

adsorption kinetics of, a 156 

CsHI, oxidation of, a 

153 

chemisorption of Hz and properties, a 35 

CH,, oxidation of, on, a 

36 

conversion of dicyclopentylmethane on, a 35 

conversions of spiro-(4,5)-decane and 

Pd-Au-H, poisoning of, with CO. a 154 

Palladium Hydride, hydrogenation on, a 

-(4,4)-nonane on, a 75 

36 

Pd(OH)& non-pyrophoric, preparation 

dehydrogenation of dicyclohexyl on a 117 

of, a 

deuteration of CIHa on, a 75 

1 I6 

electron microscopy of 141 

Pd/AI2Os, conversion of dicyciopentyl 

exoelectronic emission from, a 75 

methane on, a 

35 H %-O reaction on, a 34 

conversions of spiro-(4,5)-decane and 

intra-pellet heat and mass transfer, a 35 

spiro-(4,4)-nonane on, a 

75 

isomerisation of hexanes on, a 35 

deuteration of C,Ha on, a 

75 

specific activity of, a 35 

hydrogcnation of acctophenonc 86 

surface area of, a 35 

hydrogenation of acctylenic compounds 86 PtjC, adsorption kinetics of, a 

hydrogcnation of aromatic nitro 

156 

adsorption of unsaturated compounds 

com pounds 

86 

hydrogenation of C.,H 

on, a 156 

on, tz 

76 

conversion of dihydropyran and 

hydrogenation 01' olclinic cornpounds 86 

oroduclion of 

propyldioxene on, a 75 

vinvl acctate. (I 118 

effect of 

kduction of tail &s on, a 

KOH on activity of, a 156 

' 

116 

electron microscopy of 141 

Pd/BaSO,, hydrogenation of phosphatides 

hydrogenation of cyclohexene on, a 76 

on, a 

38 

hydrogenation of unsaturated 

Pd/CaCO,, hydrogenation of phosphatides 

compounds on, 

on, a 

a 156 

38 

preparation in sifu of, a 74 

Pd/C, adsorption of unsaturated 

recrystallisation of, a 115 

compounds on, a 

156 Pt/Cr,Os, activity and electronic emission, a 36 

carbonylation of carboxylate 

Pt/MgO, activity and electronic emission, a 36 


38 

exoelectronic emission from, a 75 

conversion of penicillins on, a 

37 Pt/polyacrylonitrile, hydrogenation of allyl 

hydrogenation of cyclohexene on, a 76 alcohols on, a 76 

hydrogenation of olefinic compounds 86 Pt/polyviuyl alcohol, properties of, a 36 

hydrogenation of phosphatides on, a 38 Pt/pumice, isomerisation of hexanes on, a 35 

hydrogenation of unsaturated 

Pt/SiO,, electron microscopy of 141 


156 

hydrogenation of cyclohexene on, a 117 

production of MAZDA with, a 76 

specific activities of, a 117 

selectivity and active sites of, a 76 Pt/SiO,-Al,O,, chemisorption and 

PdiFeCI,. synthesis of isocyanates, a 118 properties of, a 35 

Pd/polyacrylouitrile, hydrogenation of 

isomerisation of n-butane on, a 117 

ally1 alcohols on, a 76 Pt/ZrOar exoelectronic emission from, a 75 

hydrogenation of 

PtO1, reduced, hydrogenation of cyclodimethylethynylcarbinol 

on, a 156 hexene on, a 76 

PdjSiO,, hydrogenation of phosphatides 

Pt-Raney Ni, hydrogenation and 

on, a 38 oxidation on, a 36 

production of vinyl acetate, a 118 

hydrogenation of glucose on, a 156 

Pd/zeolite, resistance to poisoning of, a 76 Pt-Rh, activity of 155 

Pd-Raney Ni, hydrogenation of glucose 

atomic susceptibility of, a 155 

on, a 

156 

CzH4, oxidation of, a 153 

Pd-Rh, C,H,, oxidation of, on, a 

153 

gauze, for HNO, manufacture 2,100 


Catalysts (Conrd.) Page Electrodeposition of (Contd.) Page 

hvdroeenation of C,H,COOH on, a 155 in chloride electrolytes, a 34 

Pt-RhjC, surface area of; a 

155 Platinum, electrochemical activity of, a 115 

Pt-Sn complexes, hydrogenation of methyl 

foils, a 14 

linoleate on. a 157 Platinum-lridium, a 115 

Rhodium, alkyl complex, reaction with 

Platinum-Lead black, electrochemical 

CaH4, a 119 activity of, a 115 

black, hydrogenation of phenyl- 

Platinum Metals, thickness of deposits 13 

acetylene on, a 38 Rhodium, bright and smooth, a 154 

complexes, isomerisation of deuterio 

foils, a 74 

olefins on, a 37 Ruthenium, film, catalytic activity of, a 157 

complexes, reactions of, a I58 Electrodes, Indium, coated, thermionic 

complexes, synthesis of, a 158 emission from, a 79 

C,H,, oxidation of, a 153 evolution and dissolution of Oa at, a 34 

films, hydrogenolysis and 

wire, formation and reduction of O,, on, a 1 15 

isomerisation on, a 117 Osmium, coated, thermionic emission from, a 79 

hydrogenation of benzyl alcohol on, a 76 Palladium-Gold, pretreatment of, a 154 

hydrogenation of butyronitrile on, a 157 Platinum, adsorption and electrohydrolysis 

of ally1 chlorides, [I 118 oxidation on, a 115 

isomerisation on, a 37 

black, area changes of, a 33 

RhCOCl, (PPhs),, decarbonylation of 

cathodic protection by, a 39 

acyl halides, a 39 

coated, thermionic emission from, a 79 

carbonylation of alkyl halides, a 39 

electrolytic polishing of, a 153 

RhCI,, dimerisation of alkenes, a 

119 

gauze, hydrogenation on, a 39 

homogeneous and heterogeneous 

gauze, in 0, meter, a 116 

catalysis by, a 38 

ioiiisation of H, on, a 33 

hydride transfer on, a 37 

in fuel cells, a 78 

reaction of dienes on, a 

157 

in measurement of soil aggressiveness, 154 

RhCI(PPhs),, addition of D,, a 

77 

interaction of CO, with H on, a 73 

decarbonylation of acyl halidcs, a 38 

moveable, partially submerged, a 158 

decarbonylation of +unsaturated 

platinised, catalytic activity of, a 153 

aldehydes on, a 157 

Raney, in fuel cells, a 78 

hydrogenation of unsaturated aldehydes 

Raney, with Se and S, oxidation of 

on, a 

119 

HCOOH on, a 115 

Rh-Cu, C,H,, oxidation of, a 

153 Platinum-Gold, pretreatment of, a 154 

Rh(OH), +Pd(OH),/C, non-pyrophoric, 

Platinum Metals, adsorption and electropreparation 

of, a 

116 oxidation on, a 115 

Rh/Al,Os, deuteration of C2H, on, a 

75 Pt/asbestos, in fuel cells, a 119 

hydrogenation of C,H, on, a 

38 Pt/Nb, anode, in electrolytic dissolver, a 119 

Rh/BaSO1, hydrogenation of phenyl- 

Pt-02, cathodes, effect of HNO, on, a 33 

acetylene on, a 

38 Pt/Ti, anodes, in sea water 149 

RhjC, hydrogen,ation of benzene 

polycarboxylic acids, a 

-- 

corrosion of. a 115 

// critical evaluation, a 158 

hydrogenation of phenol 

86 durability of, a 115 

Rh/FeCI,, synthesis of isocyanates, a 118 in sea return dc system 103 

Rh/SiO?, hydrogenolyses of C,H, on, a 157 Pt-Teflon, separation of Oa by, a 154 

Rh,O, in hydroformylation, a 

119 Pt-Teflon-Ta, structural studies on, a 153 

Rh-Pd. C,HI, oxidation of, on, a 

153 Pt-plated Ni, mesh, in battery, a 158 

Rh-Pt, activity of 

155 Platinum-Rhodium, evolution and dissolution 

atomic susceptibility of, a 

155 of H, at, a 34 

deactivation of, a 

155 Reversible 02, Pt surface of, a 33 

C1H4, oxidation of, on, a 

153 Rhodium, evo!ution and dissolution of O,, at a 34 

gauze, for HNOJ, production 2, 100 Rh/Ti, corrosion of, a 115 

hydrogenation of benzoic acid, a 155 Rhodium-Platinum, evolution and 

Rh-Pt/C, surface area and activity of, a 155 dissolution of H at, a 34 

Ruthenium, comalexes, oxidation of 

Ruthenium-Platinum, adsorption and 

CgH40n,a . . 

158 electrooxidation on, a 1 I5 

C,H,, oxidation of, on, a 

153 Silver-Palladium, cathode, hydrogenation 

hydrogenation of butyronitrile, a 157 on 11 ?Q

Page 

Iridium Alloys, Iridium-Aluminium, 

crystal structure of, a 152 

Iridium-Carhon, cutectic points of, a 112 

Iridium-Osmium, lattice parameters of, a 72 

Iridium-Platinum, elastic properties of, a 33 

clectrodeposition of, a 115 

low-tcmperature specific heat of, a 70 

Iridium-Rare Earths, Laves phases of, a 72 

Iridium-Rhenium, lattice parameters of, a 72 

Iridium-Rhodium, high-tempcrature 

bchaviour of 53 

Iridium-Titanium, intermediate phases in, a 32 

Iridium-Vanadium, structure and constitution 

of, a 152 

Iridium Complexes and Compounds, 73, 1 14, 152, 153, 

154 

Johnson Matthey, 150th anniversary of 18 

new refinery in S. Africa 

131 

Magnetic Device, for study of phase changes, N 

MAZDA, production from soybean oil, a 

1 16 

76 

Osmium,,anodic corrosion of, a 74 

coating of valve emitters 15 

magnetic susceptibility of, a 152 

on Pt, electrochemistry of, a 154 

Osmium Alloys, Osmium-Chromium, 

nonstoichiometry of phases, a 31 

Osmium-Iridium, lattice parameters of, n 72 

Osmium-Platinum, lattice parameters of, (2 72 

Osmium-Rare Earths, Lavcs phases of, a 72 

Osmium-Titanium, intermediate phases in, a 32 

Osmium Complexes and Compounds 33,104 

Osmium Heptafluoride, production and properties 

of. a _. ?? 

Osmium Tetrachloride, brown and black 

forms of, n 153 

Osmium Tetroxide, vapour, negative 

staining with, a 34 

Oxidation, by transition mctal complexes 93 

Oxygen Metcr, a 116 

Pallahraze, use of, review, a 74 

Palladium, additions, sintering of W and 

W-Tho,, a 158 

cementation of, on Cu, a 

34 

characteristic temperature of, a 151 

chromaticity coefficient and luminance of, a 70 

contacts, deposits on 56 

diffusion of H, in, a 31, 78 

elcctronic structure and properties of 109 

Fermi surfacc of, a 112 

film, adsorption of CO on, a 112 

film, electrical resistance of, a 112 

flake formation, reduction of, in steel, a 11 3 

foils, deposition and thickness of, a 74 

grain boundaries, deposition of, a 112 

heat resistance of, a 150 

heat ofsublimation of, a 151 

mono- and diatomic cquilibrium in, a 71 

optical properties of, a I12 

properties of, influence ofpurity on, a 70 

vapourisation of, a 151 

wire, detection of H,, a I16 

yield point of 94 

Palladium Alloys, Palladium-Antimony, 

magnetic susceptibility of, a 

thermodynamic properties of, n 

Palladium-Cadmium, magnetic 

susceptibilityof, a 

32 

72 

32 

thermodynamic proper tics of, a 

Palladium-Cerium, expansion 

characteristics of, a 72 

Palladium-Chromium. thermoclectric power 

of, a 1 I3 

Palladium-Cohalt, electronic structure and 

properties of 109 

ordering in, a 32 

thermoelectric power of, a 113 

Palladium-Copper, deformation of, a 

72 

112, 15 1 

formation of, a 113 

resistivity and Hall effect of, a 151 

structure and mechanical properties of, a 32 


Palladium Alloys (Cod.) Page 

Palladium-Gadolinium, expansion 

characteristics of, a 72 

Palladium-Gold, deformation of, a 112, 151 

density of states and resistivity of, a 151 

electron diffraction study of, a 112 

Ha and D,solubilityin, a 151 

ordering in, a 32, 71 

oxidation of CsH I on, a 118 

permeability for HP, a 

resistivity and Hall effect of, a 

Palladium-Gold-Deuterium, neutron 

31 

151 

diffraction study of, a 

Palladium-Gold-Hydrogen, neutron 

112 

diffraction study of, a 

Palladium-Hydrogen, absorption of H,, a 

internal friction in, a 

mixing behaviour of, a 

system 

Palladium-Iron, electronic structure and 

112 

71 

72 

113 

99 

properties of 109 

magnetic properties of, a 32, 113 

thermoelectric power of, a 113 

Palladium-Lead, H, absorption in, a 31 

Palladium-Manganese, electronic structure 

and properties of 

magnctic properties of, a 

thermoelectric power of, a 

Palladium-Nickel, electronic structure and 

109 

32 

113 

propertics of 

Ha absorption in, a 

permeability for H,, a 

Palladium-Nickel-Chromium, hrazing of 

109 

31 

31 

graphite to Mo by 140 

Palladium-Phosphorus, structure of, a 32, 72 

Palladium-Platinum, heat resistance of, a I50 

Palladium-Rhodium, H, absorption in, n 31 

magnetic hehaviour of, a 71 

speed of sound in, a 

31 

Palladium-Samarium, expansion 

characteristics of, a 

72 

Palladium-Silver, as temperature indicator, a 39 

electrical resistance of, a 151 

formation of, a 113 

magnetic properties of, a 71 

mixing behaviour of, a 113 

permeability for Hp, a 31 

properties of, a 113 

speed of sound in, a 31 

Palladium-Silver-Chromium, mcchan ical 


Palladium-Silvcr-Cobalt, mechanical 

properties of, a 

Palladium-Silver-Hydrogen, electrical 

resistance of, a 

pressure-composition isotherm for, a 

Palladium-Silver-Iron, mechanical 

151 

151 

151 

properties of, a 

Palladium-Tin, Hz absorption in, u 

Palladium-Titanium, corrosion resistance of 

151 

31 

50 

Palladium-Tungsten, ordering in, a 

Palladium-Vanadium, thermoclectrical 

32 

power of, a 

Palladium-Ytterbium, expansion character- 

113 

istics of, a 

Palladium-Zirconium, binary compounds 

72 

of, a 

Palladium Chloride, catalysis of nucleophilic 

114 

reaction, a 

heating of, R 

preparation of, a 

structure and properties of Pd,CI,, 

37 

114 

I14 

114 

Palladium Complexes and Compounds 72,73,114 

Palladium Oxide, electrical conductivity, formation, 

Hail effcct of, 

Penicillins, conversion of, a 

152 

37 

Phase Changes, detection of, a 116 

Petroleum Reforming, automation of, a 154 

Platforming, mathematical description of, a 155 

Platinum, anodic corrosion of, a 74 

apparatus for DTA 

111 

a paratus in glass industry, 0, reboil theory, a 79 

ctromaticity coefficient andluminance of, a 70

Platinum (Cuntd.) Page 

coils, dctection of phase changes with, a I 16 

crucible, prcparation of glass, a 158 

depleted zones in, a 31 

dispersed, absorption of gases on, a 115 

economic history of 18 

electrical resistance of, a 70, 120 

expansion of production 9, 131 

field ion microscopy, a 31 

filament, in gas indicator, a 34 


for brazing, a 74 

heat resistance of, a I50 

oxidation kinetics of, a I50 

oxide-dispersion strengthened, a 112 

permeability for H2, a 34 

properties of, influence of purity on, a 10 

resistivity of, below 20"K, a 150 

sheet, structure of, a 70 

structure, electron diffraction study of, (I 150 

surface free energy, variation of, a 70 

surface self-diffusion, a 150 

thermal conductivity of, a 70, 150 

wire, in computer memory stores 92 

Platinum Alloys, Platinum-Carbon, eutectic 

points of, a 112 

Platinum-Chromium. nonstoichiometrv of 

phases of, a 31 

Platinum-Cobalt, magnetic properties of 71, 129 

Platinum-Comer. formation of. a 113 

magnetk'susceptibility of, a 32 

oxidation in air, a 150 

thermodynamic properties of, a 12 

Platinum-Gold, deformation and fracture 

of, a 150 

low-temperature specific heat of, a 70 

Platinum-Iridium, elastic properties of, a 33 

low-temperature specific heat of, a 70 

Platinum-Iron, activity of 0% in, a 31 

Platinum-Manganese, magnetic properties of, a 71 

Platinum-Molybdenum, intermediate phases 132 

Platinum-Niobium-Uranium, phasc change 

in a 112 

Platinum-Osmium, lattice parameters of, a 72 

Platinum-Palladium, heat resistance of, a 150 

Platinum-Rare Earth, preparation and 

structure of. a 71 

Laves phases of, a 72 

Platinum-Rhenium, gauzes, a 116 

lattice parameters of, a 72 

Platinum-Rhodium, heat rcsistancc of, a 150 

thermal conductivity of, a 150 

wire, hemispherical cmittancc of, a 19 

Platinum-Silver, formation ot, a I 13 

Platinum-Tungsten, strain gauges, foil-type 55 

Rhodium-Alloys (Contd.) Page 

Rhodium-Iron, magnetic properties, a 32, 113, 152 

phase transformations of, a 113 

structure of. a 152 

triple point, a 113 

Rhodium-Mercury, crystal structure of, a 114 

Rhodium-Nickel, magnetic susceptibility and 

specific heat of, a 152 

Rhodium-Palladium, magnetic behavionr of, a 7 I 

Rhodium-Platinum. heat resistance of. a 150 

thermal conductivity of, a 150 

wire, hemispherical emittance of, a 39 

Rhodium-Selenium, phases of, a 114 

Rhodium-Titanium, intermediate phases in, a 32 

Rhodium-Zirconium, binary compounds of, a 114 

Rhodium Chloride, hydride transfer on, a 37 

thermal conversion of, a 33 

Rhodium Complexes, H-metal bond in 

58 

x-crotylrhodium(lI1)-C IH *, a 119 

reactions of. a I58 

synthesis of, a 

158 

(PFhdaRh(l), a 

153 

with C.H,. structure of. a 

114 

with orgacometallic compounds, a 153 

Rhodium Porphyrins, synthesis and chemistry of, a 1 14 

Rustenburg Platinum Mines, production 

expanded at 9, 131 

Ruthcnium. anodic corrosion of, a 

74 

elastic properties of, a 33 

oxide glaze resistors 126 

thermal conductivity and electrical 

resistivity, a 70 

Ruthenium Alloys, Ruthenium-Rare Earths, 

Laves phases of, a 72 

Ruthenium-Zirconium, binary compounds 

of, a 1 14 

Ruthenium Boron Trifluoride, structure of. (I 33 

Ruthenium Compounds, chlororuthenates, a 78 

dodecacarbonylruthenium, reactivity of, a 73 

reaction with H,SO,, a 13 

RuBiSe. synthesis of, a 33 

Ruthenium Dioxide, glaze resistors 126 

Ruthenium Sulpbate, grecn, a 73 

Ruthenium Trichloride, structure of, a 33 

Ruthenium Triiodide, structure of, a 33 

Ruthenocene Polymers, preparation of, a 33 

Screen Printing, preparations, RuO for 126 

Sound, speed of, in Pd alloys a 31 

Spacecraft, stabilising of, a 31 

Strain Gauges, Pt-W, foil-type 55 

Platinum Chloride, Pt,CI structure and 

propel ties of, a 114 

Platinum complexes 114,153 

Platinum Dioxide, formation of, in HNO, plants, a 154 

Platinum Metals, alloys, structure of 138 

carbonyl halide complexes 148 

in fuel cells 12, 130 

thermal conductivity and clectrical 

resistivity, a 70 

Platinum Oxygen Complexes, with PPh ?, a 72 

Power Sourees, 5th Int Symp. 

12 

ResistanceThermometers, Pt, calibration of, a I59 

Pt, electrical resistivity below 11 "K, a 120 

Pt, in accurate temperature measurement, n 120 

Resistors, RuO glaze 126 

Rhodium, chlorination of, a 33 

chromaticity coefficient and luminance of, a 70 

dispcrsed, adsorption of gases on, a 115 


heat of sublimation of, a 151 

Np adsorption on, a 32 

properties of, influence of purity on, a 70 

synthesis of metal-metal bonds, a 

73 

vaporisation of, a 151 

Rhodium Alloys, Rhodium-Aluminium, crystal 

structure of, a 152 

Rhodium-Hafnium, superconductivity of, a 72 

Rhodium-Iridium, high temperature 

behaviour of 53 

Temperature Measurement, fifty years of, a 39 

hemispherical emittance of coaled wires, a 39 

Pt elcctrical resistivity below 11"K, a 120 

Ag-Pd wire for, a 39 

Thermionic Valves, 0s-coated W emitter in 15 

Thermocouples, Noble Metal, physical properties a 79 

Platinum Metal, survey of, a 79 

P1atinum:Gold-Palladium, physical 


Platinum :Platinum-Palladium-(iold, 

physical properties of, a 79 

Platinum-Platinum-Cobalt, physical 


Platinum-Platinum-Copper, physical 

properties of, (I 79 

Platinum: Platinum-Iridium. ohvsical 

I I ~ 


Platinum :Platinum-Molybdenum, physical 

propcrtics of, a 79 

Platinum: Platinum-Osmium, .. physical 


Platinum :Platinum-Rhenium. ohvsical I. ~ 

properties of a 79 

Platinum :Platinum-Tungsten, physical 


P1atinum:Rhodium-Platinum, for research 

and industry, a 159 

physical properties of, a 79 

Rhodium-Platinum :Rhodium-Platinum, 

rcfcrencc table for "six-thirty" 10 

selection of sheaths for 49

Brazing Graphite to Metals - Platinum Metals Review

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