Appeal No. 1998-2295
Application No. 08/435,902
and is selected from a variety of metals and metal alloys. Wolfla discloses refractory metal
alloys are suitable substrate materials however, titanium base alloy is not disclosed. (Col. 3,
ll. 15 to 40). Hodshire describes substrates useful as turbine engine blades. Hodshire
discloses suitable substrates include refractory metal alloys such as titanium alloys. (Col. 1,
ll. 14 to 17 and 52 to 59). Thus, the use of titanium-based alloys as the substrate in the
Wolfla invention would have been obvious to one of ordinary skill in the art because
titanium base alloys are known refractory metal alloys.
Wolfla discloses the coating is usually about 0.003 inches or thicker and formed from
a metal matrix and ceramic particles that include aluminum oxide, chromium oxide and
silicon dioxide. (Col. 2, ll. 29 to 36). Nickel and cobalt alloys are disclosed to be suitable
for the metal alloy matrix coating. (Col. 2, ll. 53 to 58). These disclosures meet the
limitations of claims 3, 4, 7 and 8.
The combination of Wolfla and Hodshire does not render the subject matter of claims
6, 9 and 12 obvious. These claims describe the selection of the substrate and coating so that
there is a relation of the coefficient of thermal expansion for the substrate and the coating.
Neither reference discloses or describes the need for the coefficient of thermal expansion for
the substrate and the coating to be about the same. The references also do not discuss the
determination of the coefficient of thermal expansion for the substrate and the selection of
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