ICMCTF 2012! - CD-Lab Application Oriented Coating Development

silica-based hydrophilic coatings in PEM fuel cells for enhanced water
management would be discussed in this talk.
3:50pm A3-2/F8-2-8 Surface morphology and catalyst activity of Sn-Pt
nanoparticles coated on anodizing aluminum oxide, C.C. Chen, C.L.
Chen, Y.S. Lai (yslai@nuu.edu.tw), National United University, Taiwan
In this work, we present the characteristics of Sn-Pt nanoparticles on the
AAO templates anodized by various electrolytes and pore widening
process. The results suggest that the specific surface area increases with the
deposition of Sn nanospheres. The growth of Sn nanospheres deposited by
sputtering is dependent on the surface roughness and the deposition time.
The contact angle between Sn nanospheres and the AAO surface increases
with the increase of surface roughness. The thickness of the Pt coating
determined by angle-resolved X-ray photoelectron spectroscopy is about 2.7
nm, equivalent to a Pt loading of 5.79 mg/cm 2 . As a result, the Sn-Pt
nanospheres on phosphoric anodized AAO show the largest electrochemical
activity area (EAA) of 57.6 m 2 Pt/g Pt. In addition, the Sn/Pt nanospheres
on oxalic anodized AAO show the EAA of 38.6 m 2 Pt/g Pt. Both of the
EAA values are larger than that of Sn-Pt nanospheres deposited on Si wafer.
Hard Coatings and Vapor Deposition Technology
Room: Royal Palm 4-6 - Session B2-2
CVD Coatings and Technologies
Moderator: S. Ruppi, Walter AG, Germany, F. Maury,
CIRIMAT, France
1:30pm B2-2-1 CVD – Opportunities and Challenges, H. Holzschuh
(helga.holzschuh@sucotec.ch), SuCoTec AG, Switzerland INVITED
Although the Chemical Vapor Deposition (CVD) technique is 160 years old
there are still opportunities and challenges. The tool manufacturing
industries have generated a growing demand for novel material applicable
for large scale production.
Due to advances in CVD technology the transfer of new coating materials
from lab scale to production size is made possible. These advances allow us
to question results generated in the last decades of CVD. They will give rise
for better understanding of the CVD processes and consequentially it will
give new chances for novel coatings.
Because of its large application potential the main focus of this work will be
on hard materials. A review of state of the art coatings and post treatments
in tool manufacturing industries will be given. But what will be the next
challenges for CVD?
2:10pm B2-2-3 SiC coatings grown by liquid injection chemical vapor
deposition using single source metalorganic precursors., G. Boisselier,
F. Maury (francis.maury@ensiacet.fr), CIRIMAT, France, F. Schuster,
CEA, France
Silicon carbide is an attractive material used for instance as protective
ceramic coating or as functional layer in electronic devices. As a result,
there is a great interest for growth processes aiming low temperatures, high
deposition rates, large-scale capacity, and other constraints imposed by the
application. To meet such requirements, SiC coatings have been grown in a
horizontal hot wall chemical vapor deposition reactor assisted by pulsed
direct liquid injection (DLI-CVD) using metalorganic compounds as single
sources. Commercial 1,3-disilabutane and polycarbosilane were used as 1:1
Si:C liquid precursors. Amorphous and stoichiometric SiC coatings were
deposited on various substrates in the temperature range 650- 750 °C and
under a total pressure of 5-50 Torr. Thickness gradients due to the
temperature profiles and the precursor depletion were observed in the
reactor axis but the thickness uniformity can be improved as a function of
the deposition conditions. Growth rates as high as 90 µm/h were obtained
using pure precursors. The injection of toluene solutions significantly
reduces the deposition rate and allows a better control of the growth rates
and of the microstructure of coatings. In that case, they exhibit a smooth
surface morphology and a very dense structure. Under the explored
conditions (reactor temperature and dewelling time of reactive species) the
decomposition rate of toluene was found negligible. As a result, the
presence of solvent vapor in the CVD reactor is not a source of carbon
contamination for the SiC coatings that keep the 1:1 stoichiometry. The
influence of the substrate temperature, the solvent and the nature of
precursor used in this DLI-CVD process is discussed and preliminary
properties are presented.
2:30pm B2-2-4 Multilayer Diamond Coatings: Theory,
Implementation in Production and Results in different Applications,
J.C. Bareiss (christian.bareiss@cemecon.de), W. Koelker, C. Schiffers, M.
Weigand, O. Lemmer, CemeCon AG, Germany
Since many years diamond coatings are a well established technique to
enhance the lifetime of cemented carbide tools in the machining of
extremely abrasive materials like graphite, carbon fibre reinforced plastics
(CFRP) and some aluminum alloys. The main advantage of crystalline
diamond films in machining applications is their outstanding hardness and
durability, but these properties also come along with an enormous
brittleness of diamond coatings. So for further improvement of the coating
and tool lifetime, we have to understand first the different failure
mechanisms, which may lead to damages and delaminations of the diamond
coating. Typical damages in diamond coatings during machining are the
formation of small cracks in the film, which may expand along the grain
boundaries and cause film delamination in large areas according to the
brittleness of diamond.
The CemeCon AG developed Multilayer CVD diamond coatings to
combine the unique durability of diamond coatings on cemented carbide
tools in machining performances with an enhanced tolerance to small cracks
and damages in the diamond film without catastrophic failure. These
multilayer diamond coatings are alternating layers of tough microcrystalline
and smooth nano-crystalline films. The achieved difference in
crystal size between these two types enables a homogeneous dissipation of
the initial crack energy by continuous change of the crack growth direction
as shown in the figure. The implementation of these multilayer coatings in
the machining of the most challenging materials like CFRP led to a further
tool performance improvement compared to completely micro- or nanocrystalline
diamond films.
CemeCon will present the theory of crack growth in these multilayer
coatings and some examples of the diamond film performance in industrial
applications.
2:50pm B2-2-5 Adhesion of the DLC film on iron based materials as a
function of gradient interlayer properties, D. Baquião, G. Faria, L. Silva
Junior, Institute for Space Research, Brazil, L. Bonetti, Clorovale
Diamantes S.A., Brazil, E. Corat, V. Trava-Airoldi (vladimir@las.inpe.br),
Institute for Space Research, Brazil
Diamond-like Carbon (DLC) films have attracted considerable interest over
due to their high hardness, low friction coefficient, high wear resistance,
high thermal conductivity, high elastic modulus, chemical inertness,
biocompatibility, and more recently because of the real possibilities of
deposition inside of the long iron based tubes for unlimited applications. In
this case very adherent DLC films can give to scientific and development
areas special opportunities to solve some problems related to transportation
of aggressive liquids like petroleum based and other minerals. The major
disadvantage of hard DLC film deposition is a relatively low adhesion of
these films on iron based substrates. To overcome the low adhesion
problems of these films on iron based substrates, different coating concepts
have been proposed, normally on high temperature condition, which is not
appropriated for iron based material structure. In this work it was proposed
an interlayer, obtained at low temperature by using low energy ion
implantation, emerging from the bulk of the substrate and overlapping with
DLC films. A convenient unique body of substrate-DLC films with
mechanical and tribological gradient properties near substrate surface was
obtained and related to its higher adhesion, lower stress, and hardness. The
interlayer and DLC films at very high growth rate were obtained by using
an enhanced asymmetrical bipolar PECVD DC pulsed power supply
system. The adhesion and hardness were evaluated by scratching test and
nano indentation, respectively. Also, a simulation of the interlayer gradient
by using TRIM/SRIM software for low energy ion implantation was
obtained with good agreement with experimental data.
3:10pm B2-2-6 Effect of the carrier gas flow rate on boron-doped
diamond synthesis using mode-conversion type microwave plasma
CVD, H.S. Shimomura (zephyros44@gmail.com), Y. Sakamoto, Chiba
Institute of Technology, Japan
Although diamond is well known an electrical insulator with a resistivity of
the order of 10^ 16 Ω・ cm, it is changed to the semiconductor by
inclusion of the dopant such as boron or phosphorus. Generally, diborane
(B2H6) or trimethyl-boron {B(CH3)3} are used as B sources to synthesize
boron-doped diamond. However, these dopants are toxic to humans. On the
other hand, trimethyl-borate {B(OCH3)3} is safety, against to B2H6 or
B(CH3)3. The investigation was carried on the effect of the carrier gas flow
rate for the boron-doped diamond synthesis using mode-conversion type
microwave plasma CVD.
The boron-doped diamond films were synthesized using mode-conversion
type microwave plasma CVD apparatus. The Si substrate was scratched by
diamond powder and then cleaned ultrasonically in acetone solution.
85 Thursday Afternoon, April 26, 2012