Ex Parte O et al

Board of Patent Appeals and Interferences

Oct 22, 2009

10935087 (B.P.A.I. Oct. 22, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________________

Ex parte HONEYWELL INTERNATIONAL INC.
____________________

Appeal 2009-006661
Application 10/935,087
Technology Center 3700
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Decided: October 22, 2009
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Before RICHARD E. SCHAFER, JAMESON LEE, and SALLY C.
MEDLEY, Administrative Patent Judges.

LEE, Administrative Patent Judge.

DECISION ON APPEAL

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A. STATEMENT OF THE CASE
This is a decision on appeal by the real party in interest, Honeywell
International Inc. (“Honeywell”), under 35 U.S.C. § 134(a) from a final
rejection of claims 1-13, 26, and 27. We have jurisdiction under 35 U.S.C.
§ 6(b). We affirm.

References Relied on by the Examiner
Allen et al. (“Allen”) US 6,435,830 B1 Aug. 20, 2002

The Rejections on Appeal
The Examiner rejected claims 1-13, 26, and 27 under 35 U.S.C.
§ 103(a) as unpatentable over Allen.

The Invention
The invention relates to a turbine blade having a protective coating to
reduce corrosion. (Spec. 3: ¶ 0010.) In particular, “the corrosion resistant
protective coating comprises a metallic compound, such as an MCrAlY alloy
(of e.g., CoCrAlY or NiCoCrAlY).” (Spec. 8: ¶ 0033.)
Claim 1 is reproduced below (App. Br. 8 Claims App’x.):
A turbine blade comprising:

a platform having a top surface, a bottom surface, and a
peripheral sidewall between said top and bottom surfaces;

an airfoil protruding from said top surface of said platform;

a blade mount extending from said bottom surface of said
platform for attaching the turbine blade to a turbine wheel; and

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a corrosion resistant protective coating of MCrAlY on said
airfoil, said top surface, said peripheral sidewall and said bottom
surface of said platform.
B. ISSUE
Has Honeywell shown that the Examiner erred in determining that one
with ordinary skill in the art would have recognized from Allen’s teachings
that a corrosion resistant coating may be applied to components of a turbine
blade, including an airfoil and the top, bottom, and peripheral sidewall
surfaces of a platform?
C. FINDINGS OF FACT
1. Allen discloses an overlay coating of MCrAlY that is applied to
surfaces of a turbine blade to provide corrosion resistance for those surfaces.
(Allen 2:26-39.)
2. Allen further discloses that in some cases coatings can add
weight to components, and with respect to turbine blades, such added weight
may undesirably increase “blade pull.” (Id. at 1:51-54.)
3. Allen recognizes that the coatings also desirably improve
oxidation, corrosion resistance and durability of the surface to which they
are applied (Id. at 1:41-50) and may be applied to “primary gas path
surfaces” (Id. at 1:54-57).
4. In one embodiment, Allen discloses that a corrosion resistant
overlay coating is applied to portions of the turbine that are “susceptible to
stress corrosion, such as the underside of the platform 18 and the neck 19 of
a turbine blade to prevent corrosion and/or stress corrosion cracking of the
blade in these locations.” (Id. at 3:51-56.)
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5. Allen further recognizes that “[o]ther components exposed to
relatively high stress and corrosive condition would also be expected to
benefit from this invention.” (Id. at 3:59-61.)
6. In another embodiment, Allen discloses that “the airfoil portion
may be covered with a metallic overlay coating” (Id. at 5:34-36) and
specifies that the coating applied to the airfoil portion may be the same as
the MCrAlY coating that is applied to the bottom surface of the platform (Id.
at 5:39-45)
7. In describing that embodiment, Allen also states that “[o]ther
combinations of coatings, of course, are also possible and the present
invention is not intended to be limited to any particular combination of
coatings on the exposed portion(s) and the shielded portion(s) of a
component.” (Id. at 5:45-49.)
D. PRINCIPLES OF LAW
A prior art reference must be considered for everything it teaches by
way of technology and is not limited to the particular invention it is
describing and attempting to protect. EWP Corp. v. Reliance Universal Inc.,
755 F.2d 898, 907 (Fed. Cir. 1985).
E. ANALYSIS
The Examiner rejected claims 1-13, 26, and 27 as unpatentable over
Allen. Claims 1, 8, and 26 are independent claims. Claims 2-7, 9-12, and
27 are ultimately dependent on, and argued collectively with, one of claims
1, 8, and 26.
Claims 1, 8, and 26 are drawn to either a turbine blade or a turbine
wheel. Each of those claims requires a platform having a top surface, a
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bottom surface, and a peripheral sidewall between those surfaces. Each
claim also requires an airfoil protruding from the top surface of the platform.
The dispute centers on the requirement in each claim of a corrosion resistant
protective coating of MCrAlY applied to the airfoil and surfaces of the
platform. Honeywell does not argue that any other claim requirements are
not disclosed in Allen.
Claims 1 and 26 each requires “a corrosion resistant protective coating
of MCrAlY on said airfoil, said top surface, said peripheral sidewall and said
bottom surface of said platform.” (App. Br. 8, 11 Claims App’x.) Claim 8
calls for “a corrosion resistant protective coating of MCrAlY on said airfoil,
said top surface, and said peripheral sidewall of said platform.” (App. Br. 9
Claims App’x.)
The Examiner pointed to Allen as teaching a turbine blade having a
corrosion resistant coating. In particular, the Examiner found that Allen
discloses (Ans. 3:16-21):
[A] corrosion resistant protective coating of CoCrAlY on the airfoil
(col. 5, lines 33-36) and on the bottom surface of the platform (col. 3,
lines 51-54; col. 4, line 1). Allen further discloses coatings are
applied on surfaces of components of gas turbines that are directly and
not directly exposed to the turbine gas path (col. 1, lines 40-43; 58-62)
to improve oxidation and corrosion resistance to these surfaces.

In light of the teachings of Allen, the Examiner reasoned that one of
ordinary skill in the art would have been led to “provide [a] corrosion
resistant coating on the airfoil, and top surface, bottom surface and
peripheral surfaces of the platform of a turbine blade to protect the same
from corrosion.” (Ans. 5:11-13.)

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Honeywell argues (App. Br. 5:11-18):
Allen teaches the strategic application of a corrosion resistance
coating to only specific portions of a turbine blade--the underside of
the platform and the neck--in keeping with its stated object of coating
portions of turbine blades not directly exposed to the hot gas stream of
a gas turbine engine. It is respectfully submitted, however, that Allen
cannot be read so broadly as to teach or suggest the application of a
corrosion resistant coating to not only the underside of the platform
and the neck, but also to the airfoil and portions of the platform. To
the contrary, it is respectfully submitted that Allen teaches away from
coating other portions of the turbine bade, such as the top surface and
the peripheral sidewall of the platform

(Emphasis in original).

Thus, according to Honeywell, Allen’s teachings are limited to
coating only the bottom surface of a platform. Honeywell also argues that
Allen teaches away from coating additional portions of the turbine blade,
such as the airfoil and the platform’s top surface and peripheral sidewall.
Honeywell’s arguments are not persuasive. Allen discloses an overlay
coating of MCrAlY that is applied to surfaces of a turbine blade to provide
corrosion resistance for those surfaces. (Allen 2:26-39.) Allen does disclose
that in some cases coatings can add weight to components, and with respect
to turbine blades, such added weight may undesirably increase “blade pull.”
(Id. at 1:51-54.) However, Allen recognizes that the coatings also desirably
improve oxidation, corrosion resistance and durability of the surface to
which they are applied (Id. at 1:41-50) and may be applied to “primary gas
path surfaces” (Id. at 1:54-57).
In one embodiment, Allen discloses that a corrosion resistant overlay
coating is applied to portions of the turbine that are “susceptible to stress
corrosion, such as the underside of the platform 18 and the neck 19 of a
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turbine blade to prevent corrosion and/or stress corrosion cracking of the
blade in these locations.” (Id. at 3:51-56.) Allen further recognizes that
“[o]ther components exposed to relatively high stress and corrosive
condition would also be expected to benefit from this invention.” (Id. at
3:59-61.)
In another embodiment, Allen discloses that “the airfoil portion may
be covered with a metallic overlay coating” (Id. at 5:34-36) and specifies
that the coating applied to the airfoil portion may be the same as the
MCrAlY coating that is applied to the bottom surface of the platform (Id. at
5:39-45). In describing that embodiment, Allen also states that “[o]ther
combinations of coatings, of course, are also possible and the present
invention is not intended to be limited to any particular combination of
coatings on the exposed portion(s) and the shielded portion(s) of a
component.” (Id. at 5:45-49.)
In view of those teachings, we reject Honeywell’s argument that Allen
teaches away from a corrosion resistant coating applied to portions of the
turbine blade other than the bottom surface of the platform, such as the
airfoil and the top surface and peripheral sidewall of the platform. Indeed,
Allen expressly discloses an embodiment in which the airfoil, which is
exposed to gas flow within the turbine and which protrudes from the top
surface of the platform, is coated with the same MCrAlY coating as that
applied to the bottom surface of the platform.
Furthermore, one with ordinary skill in the art would have recognized
that surfaces of the platform, such as its top surface and peripheral sidewall,
which are directly adjacent to the airfoil also lie within the path of the gas
passing through the turbine. That is, those top and side surfaces of the
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platform are the type of surfaces “exposed” to gas within the turbine that are
expressly disclosed in Allen as benefiting from a coating that provides
corrosion resistance and prevents stress corrosion cracking.
Even if Allen’s invention is not specifically concerned with coating
the top surface and peripheral sidewall of the platform, a prior art reference
must be considered for everything it teaches by way of technology and is not
limited to the particular invention it is describing and attempting to protect.
EWP Corp., 755 F.2d at 907. A person of ordinary skill in the art is also a
person of ordinary creativity, not an automaton. KSR Int’l Co. v. Teleflex
Inc., 550 U.S. 398, 421 (2007). In this case, one with ordinary skill and
creativity in the art would have readily recognized from Allen’s teachings
that a coating that prevents corrosion and stress cracking for some surfaces
of a turbine blade, such as the airfoil and bottom surface of a platform,
would also provide those benefits to other surfaces such as the top surface
and peripheral wall of the platform.
For all the foregoing reasons, we sustain the rejection of claims 1-13,
26, and 27 as unpatentable over Allen.
F. CONCLUSION
Honeywell has not shown that the Examiner erred in determining that
one with ordinary skill in the art would have recognized from Allen’s
teachings that a corrosion resistant coating may be applied to components of
a turbine blade, including an airfoil and the top, bottom, and peripheral
sidewall surfaces of a platform.
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G. ORDER
The rejection of claims 1-13, 26, and 27 under 35 U.S.C. § 103(a) as
unpatentable over Allen is affirmed.

AFFIRMED

KMF

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