Appeal No. 2004-2027
Application No. 09/670,189
appealed claim 1 or 12.
We cannot agree with the examiner’s analysis and conclusion.
Warnes discloses a method of making CVD [chemical vapor
deposition] active element modified platinum aluminide diffusion
coatings on a nickel or cobalt base superalloy substrate, wherein
a platinum layer is first deposited on the substrate and then
Al+Si+Hf+ optionally Zr and/or other active elements are CVD
codeposited to produce diffusion coatings useful in, e.g.,
service applications in the hot turbine section of a gas turbine
aircraft engine. (Column 2, lines 55-64.) Warnes further
teaches:
The substrate first was electroplated with Pt (9-11
milligrams/centrimeter [sic] squared) as described
above without any diffusion heat treatment of the
platinum layer prior to CVD codeposition...The second
step was conducted at a substrate temperature of 1080º
C. using coating gas mixture comprising 4 volume %
silicon tetrachoride [sic] and aluminum trichloride
(greater than 90% by volume aluminum trichloride), 79.5
volume % hydrogen, 15 volume % Ar, and 1.5 volume %
HfCl4 and ZrCl4 [(coating gas flow rate of 200 standard
cubic feet per hour (scfh) and total pressure of 150
Torr]. The coating gas mixture was generated by
passing high purity hydrogen (e.g. less than 30 ppb
impurities) and high purity hydrogen chloride (e.g.
less than 25 ppm impurities) in mixture of hydrogen/10
volume % HCl over a high purity 99.999% pure source of
aluminum and then passing the mixture over a high
purity 99.999% pure source of silicon with both sources
at 290º C. (sources external of retort) to form a
mixture of aluminum trichloride and silicon
tetratrichloride [sic] as disclosed in copending
application Ser. Nos. 08/197,349 and 08/197,497 of
common assignee herewith, the teachings of which are
incorporated herein by reference to this end. A
5
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 Next
Last modified: November 3, 2007