Appeal No. 2002-1401
Application No. 09/187/226
Claims 13 and 14
The appellants’ claim 13 requires that the pore ratio of the
composite material is minimized by using aluminum nitride
particles having first and second particle sizes, wherein the
particles having the first particle size, R, are present in
3-5 times the volume concentration of the particles having the
second particle size, 3R to 5R.
The appellants argue that Premkumar “is silent regarding the
particle size that should provide the advantages of successfully
controlling the porosity of the composite material or base
material” (brief, page 14).
Actually, Premkumar discloses that substantially porosity
free metal matrix composites can be produced by using particles
having a distribution of sizes so as to obtain interstitial
filling (col. 5, lines 54-63). This disclosure of interstitial
filling would have indicated to one of ordinary skill in the art
that the small particles, which fill in the spaces between the
large particles, must be present in a relatively large volume
fraction. Given this disclosure, the optimum relative sizes and
volumes of the particles recited in the appellants’ claim 13
would have been determinable by one of ordinary skill in the art
aluminum-silicon alloy (col. 2, lines 42-44) is the same or
substantially the same as that obtained by mixing the appellants’
silicon lumps with the aluminum base material, and the appellants
have provided no evidence or argument to the contrary.
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