Appeal No. 1998-2409
Application 08/398,259
(col. 2, lines 29-50). McGill states that “the aim of the
present invention is to improve the adherence, durability and
corrosion resistance of a thermal barrier system without
affecting the prime purpose of said system, namely to reduce
substrate metal surface temperature thus allowing current high
temperature materials to operate effectively in hotter combustion
gas streams” (col. 3, line 57 - col. 4, line 2).
The examiner argues that it would have been obvious to one
of ordinary skill in the art to optimize Osozawa’s sulfur content
within Osozawa’s range of at most 10 ppm, thereby arriving at
appellants’ free sulfur content of less than about 1 ppm (answer,
pages 4-5). Appellants, however, have selected their free sulfur
content for the purpose of reducing the tendency of the
protective system to debond (specification, page 6, lines 7-11).
Osozawa, on the other hand, selected his sulfur content, which
has not been established by the examiner as being free sulfur
rather than combined or total sulfur, to improve hot workability
(col. 2, lines 46-49). The examiner has not explained why
Osozawa and McGill would have led one of ordinary skill in the
art to optimize Osozawa’s sulfur content for appellants’ purpose,
or why it reasonably appears that optimizing Osozawa’s sulfur
content for the different purpose disclosed by Osozawa would
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