Appeal No. 1999-0764
Application 08/745,199
aluminum-silicon coating on a metal substrate that uses a diffusion mixture containing
aluminum, silicon and sodium chloride as an activator (e.g., col. 6). This method differs from the
claimed method essentially in the presence of the sodium chloride instead of an ammonium
halide activator in the diffusion mixture. The examiner relies on the use of ammonium halide
and sodium chloride activators in a method of chromizing the surface of a metal substrate in
Davis ‘501 to show the interchangeability of such activators, and finds that one of ordinary skill
in this art would have substituted the ammonium halide activators for the sodium chloride
activators in the method of Krutenat because Davis ‘701 “teaches that these two compounds are
equivalent [and] thus one would expect them to behave identically” (answer, page 4).
Appellants submit that the teachings of Davis ‘501 with respect to the halide activator in
the chromizing method are not applicable to halide “activators for an aluminum and silicon
diffusion coating system,” and point to the discussion of the differences in the two methods in
the declaration of appellant Bayer3 (brief, pages 4-5; see also brief, pages 5-7, and reply brief,
pages 1-2).
The examiner does not address the issues raised by appellants, contending instead that
“one of ordinary skill in this art would have had a reasonable expectation of success in
substituting an ammonium halide activator for the sodium halide activator taught by Krutenat . . .
because a sodium activator works in an Al-Si system and a Cr system, as evidenced by Krutenat
and Davis ‘501, and this would have suggested to one of ordinary skill in the art that activators
disclosed by Davis ‘501 as equivalent to sodium chloride would be likely to work in the Al-Si
system of Krutenat” (answer, page 6). In this respect, the examiner further points to a statement
by declarant Bayer that he and others were “surprised” by the results reported in the declaration
because “[w]e expected similar results” from the ammonium chloride salts and the sodium
chloride salts (declaration, ¶ 4), and contends that “Mr. Bayer’s expectation of comparable results
using either NH4Cl or NaCl supports the Examiner’s position that one of ordinary skill in the art
would have expected an ammonium salt to work in the Al-Si system taught by Krutenat”
(answer, page 7).
3 The declaration under 37 CFR § 1.132 was submitted November 17, 1997 (Paper No. 4).
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