A Comprehensive Treatise on Inorganic and Theoretical Chemistry

216 INORGANIC AND THEORETICAL, CHEMISTRY
are magnetic with a maximum at 10 per cent, of chromium ; the magnetic transition
point is 390° to 400°. E. Janecke discussed the ternary systems involving
platinum-chromium-copper alloys, also the platinum-chromium-silver alloys,
and the platinum-cnromium-gold alloys.
C. Barus, CF. Dreibholz, W. Guertler, and W. Lederer prepared some platinummolybdenum
alloys according to the method employed for the platinum-chromium
alloys. M. G. Korsunsky said that solid soln. are formed. C. Barus measured the
electrical resistance. P. J. Hjelm found that an alloy with 50 per cent, of
molybdenum was pale grey, hard, and brittle, and an alloy with 20 per cent, of
molybdenum was bluish-grey, hard, brittle, with a granular fracture. J. J. and
F. de Elhuyar, and E. Haagn and W. C. Heraeus prepared platinum-tungsten
alloys from the two metals ; and E. Weintraub, by drawing thin wires of the two
metals and melting them in the electric furnace. The alloys with 20 to 6O per
cent, of platinum are malleable, and harder than platinum. M. G. Korsunsky
said that solid soln. are formed. The alloy also resists oxidation when heated in
air, and attack by chemical reagents better than platinum. L*. Muller determined
the liquidus curve of some platinum-tungsten alloys, and the results are summarized
in Fig. 55. Measurements of the electrical resistance were also made.
I. E. AdadarofE and co-workers studied the oxidation of ammonia using the
platinum-tungsten-silver, and platinum-tungsten-rhodium alloys as catalysts.
T. Meiffren prepared a platinum-gold-copper-tungsten alloy.
J. Aloy electrolyzed molten potassium chlorouranate, with platinum electrodes,
and obtained a platinum-uranium alloy.
C. Barus 17 prepared platinum-manganese alloys by melting a mixture of the
two elements in the oxyhydrogen flame. He studied the electrical resistance of
some alloys. W. Guertler made some observations on these alloys.
E. Janecke discussed the ternary systems involving platinum-manganese-copper
alloys, and the platinum-manganese-silver alloys. W. Goedecke, F. Beck, and
A. Schulze studied the thermoelectric force of platinum against a platinum-rhenium
alloy.
H. St. C. Deville 18 reported native ferroplatinuvn associated with 13 per cent,
of iron ; A. Breithaupt, J. J. Berzelius, G. Osann, A. von Mussin-Puschkin, and
H. Debray reported up to 19 per cent, of iron ; and other observations have been
made by A. Terreil, A. Daubree, and H. St. C. Deville and H. Debray. J. Stodart
and M. Faraday prepared some alloys, and some of their properties were examined
by R. A. Hadfield, and H. List. E. D. Clarke found that platinum-iron alloys
can be obtained by heating equal parts of the two metals in an oxyhydrogen
flame ; C. Barus employed a similar process ; W. .Lewis, and A. F. Gehlen said
combination does not occur in an ordinary furnace, although H. St. C. Deville
said that the metals unite at a comparatively low temp. E. Isaac and G. Tammann
melted mixtures with up to 50 per cent, of platinum in a porcelain tube, and
mixtures with 50 to 90 per cent, of platinum in a magnesia tube, and in an atm.
of nitrogen. H. St. C. Deville and H. Debray obtained an alloy by heating platinum
with 10 parts of pyrite, and 1 part of borax, and treated the product in turn with
nitric acid, potash lye, and hydrofluoric acid. J. B. J. D. Boussingault dissolved
equal parts of the two metals in aqua regia, removed the excess of acid by evaporation,
added aq. ammonia, and heated the washed precipitate in a current of hydrogen
at a low red-heat. The alloy was pyrophoric. F. Mylius and O. Fromm said that
iron in dil. soln. of platinum salts forms an iron-platinum alloy. F. E. Carter
discussed the contamination of platinum by contact with iron during annealing
operations ; and in rolling, and wire drawing iron may be embedded in the surface
of platinum, and on subsequent heating, dissolved by the metal. Hence, before
reheating, the adherent iron should be removed by hot, cone, hydrochloric
acid. N. Ageeft and M. Zamotorin studied the diffusion of platinum in iron ; and
W. C. Roberts-Austen showed that at 4:92° 1-69 grms. diffuse per sq. cm. per
day, or 1*96 X 10~ 5 grm. per second in iron. M. G. Korsunsky said that solid