Appeal No. 1998-2295
Application No. 08/435,902
BACKGROUND
Appellants’ invention relates to materials used in aircraft turbine engines. More
specifically the invention is directed to titanium based alloys coated with a protective
coating. The protective coating is composed of a mixture of matrix metal and ceramic
particles. The ceramic particles are embedded in the matrix metal. The coating is said to
provide protection against diffusionally based oxidation and hot corrosion and hot erosion.
(Specification, pp. 2 and 3). The coating is also said to avoid the creation of thermal strains
and stress that would result due to differences in thermal expansion coefficients of the
coating and metallic substrate. (Specification, p. 3). The coefficient of thermal expansion
of the coating relates to the relative amount of metallic constituents, which have a high
coefficient of thermal expansion, and the ceramic constituents, which have a low coefficient
of thermal expansion. Thus the components of the coating are selected to provide a
coefficient of thermal expansion that matches the substrate. (Specification, p. 4). Claims 1,
9 and 12, which are representative of the claimed invention, appear below:
1. An article comprising:
a substrate formed of a first metal comprising a titanium-based alloy; and
a coating directly in contact with the substrate, the coating being formed of a
mixture comprising a second metal and a ceramic, wherein the ceramic is
selected from the group consisting of an oxide, a nitride, and a silicide.
9. An article comprising:
a substrate which is an uncooled component of a gas turbine engine, the substrate
being formed of a first metal comprising a titanium-base alloy; and
-2-
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