Ex parte VAKIL

Board of Patent Appeals and Interferences

Mar 10, 1998

08024034 (B.P.A.I. Mar. 10, 1998)

Application for patent filed March 1, 1993.1
1
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today (1) was not written for
publication in a law journal and (2) is not binding precedent of the Board.
Paper No. 13
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte HIMANSHU B. VAKIL
_____________
Appeal No. 94-4428
Application 08/024,0341
______________
ON BRIEF
_______________
Before JOHN D. SMITH, ELLIS and OWENS, Administrative Patent
Judges.
JOHN D. SMITH, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal pursuant to 35 USC § 134 from the final
rejection of claims 1 through 11 and 14 through 16.
Claim 1 is representative and is reproduced below:
Appeal No. 94-4428
Application 08/024,034
2
1. A method of producing a spallation-resistant
protective layer on the surface of a nickel- or cobalt-based
superalloy substrate, said method comprising the steps of:
depositing an adherent metal aluminide layer on
said substrate, the metal aluminide in said layer being nickel
or cobalt aluminide;
depositing an aluminum oxide layer on the
surface of said metal aluminide layer; and
heating said aluminum oxide layer.
The references of record relied upon by the examiner are:
Lory et al. (Lory) 4,675,089 Jun. 23, 1987
Strangman et al. (Strangman) 4,880,614 Nov. 14,
1989
Morosanu, Thin Films Science and Technology, 7, ?Thin Films by
Chemical Vapour Deposition?, pages 429-430 and 445 (1990).
Kiyono et al. (Kiyono) 59-181318 Oct. 15, 1984
(Japanese Kokai Patent)
Claims 1 through 3 and 6 through 8 stand rejected under
35 USC § 103 over Strangman in view of Lory. Claims 4 and 5
stand similarly rejected under the same section of the statute
further in view of Morosanu. Additionally, claims 9 through
11 stand rejected under 35 USC § 103 in view of the combined
teachings of Strangman, Lory, and Kiyono.
Appeal No. 94-4428
Application 08/024,034
3
We reverse.
The subject matter on appeal generally relates to the
formation of protective coatings on nickel- and cobalt-based
superalloy articles of the type used as gas turbine parts. It
is known in the prior art to deposit oxidation-resistant
coatings on the surfaces of such articles and typically, such
coatings are nickel or cobalt aluminide having surfaces which
oxidize to form an aluminum oxide (alumina) scale which is
tough, adherent and resistant to attack by oxidation
(Specification, page 1, lines 27-33). A problem with alumina
scales formed by the prior art process is that they tend to
spall from the surface of the part, largely as a result of the
difference between the coefficient of thermal expansion of the
underlying superalloy and the alumina scale (Specification,
page 2, lines 1-8). A result of such spallation is further
oxidation of the surface aluminide layer to alumina, which can
ultimately deplete the aluminum available on the surface
(Specification, page 2, lines 8-16).
Appellant’s invention is said to be based on the
discovery of a method to produce a spallation-resistant
alumina layer on an aluminided superalloy article. This is
Appeal No. 94-4428
Application 08/024,034
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achieved by the deposition of a layer of alumina on the nickel
or cobalt aluminide surface, typically by chemical vapor
deposition, followed by heat treatment, typically at a
temperature in the range of about 900-1200EC. As disclosed in
appellant’s specification at page 7, lines 18 through 21, the
heat treatment converts a mostly amorphous aluminum oxide
layer under tensile stress into a spallation-resistant
aluminum oxide layer, which is a stable form of alpha-alumina.
Appellants further indicate that it is believed that the heat
treatment causes tensile cracking of the top alumina layer,
making possible its expansion and contraction without the
production of stresses which result in spallation. Finally, a
thermal barrier coating such as a zirconia coating may be
further deposited on the alumina coated article. See, for
example, dependent claims 2 and 3.
At the outset, we note the examiner’s contention in the
Answer at page 2, which is not disputed by appellant, that the
appealed claims stand or fall together. Thus our focus in
this decision is primarily directed to the rejection of
independent claim 1 for obviousness (35 USC § 103) over
Strangman in view of Lory.
Appeal No. 94-4428
Application 08/024,034
Rather than focusing on multiple differences in multiple claims, the examiner2
should treat and focus on each claim individually. Claim 1, for example, only requires a
step of ?heating said alumina oxide layer? without any reference to temperature and time
parameters.
5
According to the examiner, Strangman teaches a method of
producing a spallation-resistant protective layer on the
surface of a nickel or cobalt based superalloy substrate
comprising, inter alia, depositing an alumina layer on the
surface of a deposited nickel or cobalt aluminide layer.
However, according to the examiner, Strangman does not
disclose heating the alumina layer at about 900-1200EC for
about 1-2 hours. See the Answer at page 3. The examiner2
further contends that it would have been obvious to one of
ordinary skill in the art to have annealed the deposited
alumina layer at a 1000EC in Strangman’s method for converting
the deposited layer into a polycrystalline layer as suggested
by the secondary reference to Levy, ?because it is well known
that high temperature annealing can enhance the formation of
the crystalline structure of CVD films?. See the Answer at
page 4, second full paragraph. The examiner further explains
in the Answer at pages 9 and 10 that it would have been
obvious to have applied the post-annealing as suggested by
Appeal No. 94-4428
Application 08/024,034
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Levy in Strangman’s process ?to crystallize the deposited
amorphous alumina films as stated in the specification, page
7, lines 14 through 31?.
Appellant points out that Strangman is directed to the
superalloy art for the formation of articles of the type used
as gas turbine parts while Lory is directed to the art of
integrated circuits. Thus appellant contends, and we agree,
that the teachings of these references cannot be legitimately
combined because they are from different arts. No disclosure
in Lory, in our view, is reasonably pertinent to the
particular problem with which appellant is involved, which
problem may be broadly characterized as the spalling of
alumina scales caused as the result of the difference between
the coefficient of thermal expansion of an underlying
superalloy structure and alumina. Again, see the
specification at page 2, lines 3 through 10. Thus, we agree
with appellant that Lory cannot be characterized as ?analogous?
art. See, for example, In re Deminski, 796 F.2d 436, 442, 230
USPQ 313, 315 (Fed. Cir. 1986); In re Wood, 599 F.2d 1032,
1036, 202 USPQ 171, 174 (CCPA 1979).
We further observe that the examiner’s contention that it
Appeal No. 94-4428
Application 08/024,034
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would have been obvious to crystallize an amorphous film in
Strangman’s process overlooks the fact that Strangman deposits
a high purity, dense chemical vapor deposition alpha alumina
layer, i.e., a crystalline layer (column 5, lines 6 through
11). In this regard, we take official notice that alpha
alumina is crystalline and is composed of fine hexagonal
crystalline plates. See Kirk-Othmer, 3rd Edition, Volume 2,
pages 218, 219 and 233-236, particularly page 233, (1978),
copy attached. Accordingly, the examiner’s rejection of the
appealed claims cannot be sustained.
We remand this application to the examiner for further
consideration of the disclosure of Strangman at column 6,
lines 13 through 18 which has apparently been overlooked by
the examiner and appellant. This disclosure appears to
suggest that an alpha alumina coated superalloy structure is
preheated prior to exposure to a ceramic coating vapor. The
examiner should determine whether such a ?preheating step?
reads on the claimed step of ?heating said aluminum oxide
layer? which is all that is required by the language of
appealed claim 1. Thus, the examiner should determine based
on the above disclosure in Strangman whether appealed claim 1
Appeal No. 94-4428
Application 08/024,034
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is unpatentable under either 35 USC
§ 102(b) or alternatively under 35 USC § 103. The examiner
may also wish to extend his search to determine whether or not
it would have been obvious to form the alpha alumina layer
described in Strangman by a process of heat treating a
deposited amorphous film. These questions are best resolved
at the examiner’s level because the examiner has greater
accessibility to the prior art, and appellant has the
opportunity to argue the issues absent the restrictions which
tie the examiner’s hands regarding a rejection made by the
Board under 37 CFR § 1.196(b).
We remind the examiner of his ability to reopen
prosecution at any time prior to issue for the purpose of
ensuring the validity of the claims. As stated by the Supreme
Court in Graham v. John Deere, 383 U.S. 1, 18, 148 USPQ 459,
467 (1966):
[I]t must be remembered that the primary
responsibility for sifting unpatentable
material lies in the Patent Office. To
await litigation is - for all practical
purposes - to debilitate the patent system.
In summary, each of the examiner’s stated rejections
Appeal No. 94-4428
Application 08/024,034
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under 35 USC § 103 is reversed. This application is remanded
to the examiner to consider the above matters. By virtue of
its ?special? status, this application requires an immediate
action,
MPEP § 708.01(d). It is important that the Board be informed
promptly of any action affecting the appeal in this case.
REVERSED and REMANDED
)
JOHN D. SMITH )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
JOAN ELLIS )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
TERRY J. OWENS )
Administrative Patent Judge )
Appeal No. 94-4428
Application 08/024,034
10
General Electric Company
CRD Patent Docket Rm 4A59
P.O. Box 8, Bldg. K-1-Salamone
Schenectady, NY 12301