Ex Parte Nagaraj et al

Board of Patent Appeals and Interferences

Apr 24, 2008

11113197 (B.P.A.I. Apr. 24, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte BANGALORE A. NAGARAJ,
EVA Z. LANMAN, DEBORAH A. SCHORR,
THOMAS J. TOMLINSON, RAYMOND W. HEIDORN,
DAVID A. KASTRUP and CRAIG D. YOUNG
____________

Appeal 2008-2142
Application 11/113,197
Technology Center 1700
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Decided: April 24, 2008
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Before EDWARD C. KIMLIN, CHUNG K. PAK, and
JEFFREY T. SMITH, Administrative Patent Judges.

KIMLIN, Administrative Patent Judge.

DECISION ON APPEAL

This is an appeal from the final rejection of claims 1-11, 13-24, 39
and 40. Claims 1 and 40 are illustrative:
1. A method for applying a thermal barrier coating to an underlying
metal substrate where the metal substrate has an overlying aluminide
diffusion coating, the method comprising the steps:
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(1) roughening the aluminide diffusion coating to make it more
receptive to adherence of a plasma spray-applied overlay alloy bond coat
layer; and

(2) plasma spraying an overlay alloy bond coat material on the
roughened diffusion coating to form an overlay alloy bond coat layer.

40. A method for applying a thermal barrier coating to an underlying
metal substrate where the metal substrate has an overlaying aluminide
diffusion coating, the method comprising the steps:

(1) grit blasting the aluminide diffusion coating to remove the
diffusion coating from the metal substrate; and

(2) plasma spraying an overlay alloy bond coat material on the metal
substrate to form an overlay alloy bond coat layer.

The Examiner relies upon the following references as evidence of
obviousness:
Thermal Spraying: Practice, Theory, and Application, American Welding
Society, Inc., pages 16-19, 22 (1985).

Draghi 5,972,424 Oct. 26, 1999
Sangeeta 5,976,265 Nov. 2, 1999
Wolkers US 2003/0082297 A1 May 1, 2003

Appellants' claimed invention is directed to a method for applying, or
repairing, a thermal barrier coating on an underlying metal substrate that has
an overlaying aluminide diffusion coating. The method entails roughening
the aluminum diffusion coating, such as by grit blasting and plasma spraying
an overlay alloy bond coat material on the roughened surface. A ceramic
thermal barrier coating is plasma sprayed on the overlay alloy bond coating.

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Appealed claims 1-11, 13-24, and 39 stand rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Draghi in view of Thermal Spraying:
Practice, Theory, and Application (TS).1 Claim 40 stands rejected under
35 U.S.C. § 103(a) as being unpatentable over Wolkers in view of Sangeeta.
We have carefully considered each of Appellants' arguments for
patentability. However, we are in complete agreement with the Examiner's
reasoned analysis and application of the prior art, as well as her cogent and
thorough disposition of the arguments raised by Appellants. Accordingly,
we will adopt the Examiner's reasoning as our own in sustaining the
rejections of record, and we add the following for emphasis only.
We consider first the Examiner's § 103 rejection of claims 1-11,
13-24, and 39 over the combined teachings of Draghi and TS. Draghi,
like Appellants, discloses a method for applying and repairing a thermal
barrier coating on an underlying metal substrate where the metal substrate
has an overlaying aluminide diffusion coating and a plasma spray-applied
overlay alloy bond coat layer. While Draghi does not expressly teach
roughening the aluminide diffusion coating, the Examiner properly points
out that the reference specifically teaches performing mechanical operations
for preparing the flash coat comprising a diffusion aluminide to receive a top
coat of ceramic material (col. 6, ll. 28 et seq.). Since TS evidences that it
was known in the art to roughen a substrate to improve bonding to a
thermally sprayed coating, we are convinced that one of ordinary skill in the
art would have understood the mechanical operation of Draghi to include

1 For this rejection Appellants separately argue only claims 19-24, as a
group. Accordingly, claims 1-11, 13-18, and 39 stand or fall together, as do
claims 19-24.
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roughening. Moreover, it was notoriously well known in the art to roughen
the surface of a substrate to enhance adhesion to a subsequent coating on the
substrate since the roughening treatment provides a greater surface area for
contact with the coating. As for the claimed step of plasma spraying an
overlay alloy bond coat material on the roughened diffusion coating, Draghi
teaches that Appellants' alloy may be applied to the diffusion coating before
the ceramic layer is applied, and we find that it would have been obvious to
roughen the diffusion coating to increase bonding to the alloy layer.
Furthermore, appealed claim 1 does not require that the alloy bond coat
directly contact the diffusion coating but only that it overlay it.
Appellants cite the dictionary definition of Draghi's "peening" to
support their argument that peening is not a roughening treatment. The
Examiner, in response, cites prior art to demonstrate that peening may be
used in the art to roughen a substrate. We do not agree with Appellants that
the Examiner's citation of the prior art evidence in refutation of Appellants'
dictionary citation is tantamount to an improper reliance on new prior art
that requires a re-opening of prosecution. We concur with the Examiner that
the cited evidence is not necessary to support the Examiner's § 103 rejection
and it is entirely proper for the Examiner to cite additional evidence in
rebuttal of Appellants' definition of a term in the art.
Concerning claims 19-24, Appellants maintain that Draghi does not
teach or suggest “a thermal barrier coating applied by physical vapor
deposition (PVD) is replaced with a plasma-sprayed thermal barrier coating”
(Br. 8, second para.). However, we agree with the Examiner that Draghi
teaches that it was well known in the art to apply a ceramic thermal barrier
coating by PVD or by thermal spraying methods. Since Draghi teaches that
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plasma spraying produces a porous structure when desired, we find no error
in the Examiner's conclusion that "it would have been obvious to one of
ordinary skill in the art to replace any initial thermal barrier coating,
including those applied by physical vapor deposition, with the plasma
sprayed coating if the porous structure is desired" (Ans. sentence bridging
pages 15-16). Indeed, we find that it would have been obvious for one of
ordinary skill in the art to apply both the initial thermal barrier coating and
the replacement coating by either PVD or plasma spraying. Appellants have
proffered no objective evidence of criticality associated with the methods of
applying the initial and replacement thermal barrier coating.
Turning to the § 103 rejection of claim 40 over Wolkers in view of
Sangeeta, we subscribe to the Examiner's rationale that it would have been
obvious for one of ordinary skill in the art to use the aluminide diffusion
coating of Sangeeta to replace the alloy initial bond coating of Wolkers and
to employ grit blasting to remove the initial bond coating. As explained by
the Examiner, Wolkers expressly teaches that the initial bond coat that is
removed can be an alloy of MCrAlY “or other bond coat” (see para. 0024),
and Sangeeta provides evidence that one of ordinary skill in the art would
have reasonably expected an aluminide diffusion coating to be suitable for
the other bond coat taught by Wolkers. Since Wolkers specifically teaches
that the re-applied bond coat is the MCrAlY alloy, the skilled artisan would
have found it obvious to use the alloy to replace either the same alloy or
other bond coat of an aluminide diffusion coating. Appellants cite no
evidence of criticality with respect to replacing the initial aluminide
diffusion coating with an alloy bond coat material.
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As a final point, we note that Appellants base no argument upon
objective evidence of nonobviousness, such as unexpected results, which
would serve to rebut the inference of obviousness established by the applied
prior art.
In conclusion, based on the foregoing and the reasons well stated by
the Examiner, the Examiner's decision rejecting the appealed claims is
affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).
AFFIRMED

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