Appeal No. 2002-2142 Page 5
Application No. 09/276,858
Appellants have chosen to describe their invention in terms of a process of obtaining
certain physical characteristics when making a nickel base superalloy single crystal casting. For
instance, claim 1 is directed to a method of reducing as-cast metallic surface scale. But that does
not change the essence of the process which is really a method of forming a single crystal casting
by molding a nickel base superalloy of a particular composition. Wukusick describes a process
of forming single crystal castings of nickel base superalloys. In the instances that Wukusick
describes a process of making single crystal castings of compositions with the inherent properties
recited in the claim, that claim is anticipated.
Particularly, we find that claims 1-4, 9-11, 17, and 18 are anticipated by Wukusick.
Focusing on claim 1 to illustrate, we note that this claim is directed to forming single crystal
castings of nickel base superalloy containing Cr, Co, Mo, W, Ta, Al. In addition, the alloy
contains C in a concentration “high enough to substantially reduce formation of said as-cast
metallic surface scale during solidification.” According to Appellants’ specification, carbon
concentrations greater than 0.04 wt. % are effective to substantially reduce as-cast metallic scale
(specification at 7, ll. 9-13). Not only does Wukusick describe nickel base superalloy
compositions with carbon concentrations greater than 0.04 wt. % (Table I, preferred and most
preferred), those alloy compositions contain Cr, Co, Mo, W, Ta, and Al in concentrations
encompassed by the range of alloy compositions described in the specification at page 6, lines
20-25 for which an increase in carbon content of greater than 0.04 wt.% results in scale reduction
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