Ex Parte Hu et al

Board of Patent Appeals and Interferences

Jul 6, 2007

10936925 (B.P.A.I. Jul. 6, 2007)

The opinion in support of the decision being entered today
is not binding precedent of the Board.

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte YIPING HU, WILLIAM F. HEHMANN,
and FEDERICO RENTERIA
_______ _ __

Appeal 2007-1852
Application 10/936,925
Technology Center 1700
____________

Decided: July 6, 2007
____________

Before CHUNG K. PAK, CATHERINE Q. TIMM, and
LINDA M. GAUDETTE, Administrative Patent Judges.

GAUDETTE, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal from the Examiner’s final rejection of claims 10-13
and 15-18, the only claims pending in this application. We have jurisdiction
over the appeal pursuant to 35 U.S.C. § 6(b).
We affirm.
Appellants’ invention relates to methods for coating turbine engine
components, such as turbine blades, to prevent erosion due to wear,
Appeal 2007-1852
Application 10/936,925

corrosion, oxidation, thermal fatigue, foreign particle impact, and other
hazards. (Specification [0001]). The method utilizes a cold gas-dynamic
spray technique to coat high pressure turbine (HPT) component surfaces
with mixtures of MCrAlY alloys and abrasive materials. (Specification
[0012]). Independent claim 10 is illustrative of the invention:
10. A method for coating a surface of a turbine component with an
environment-resistant and wear-resistant material, comprising the step of:

forming an abrasive coating by cold gas-dynamic spraying a powder
material on the turbine component surface, the powder materia1 comprising
a mixture of:

MCrAlY powder, with M being selected from Ni, Co and mixtures
thereof, and

an abrasive powder being selected from the group consisting of
carbides, and oxides; and

heat treating the turbine component at a temperature sufficiently high
to consolidate and homogenize the abrasive coating after the cold gas-
dynamic spraying.

The Examiner relies on the following prior art references to show
unpatentability:
Matarese US 4,744,725 May 17, 1988
Benoit US 5,551,840 Sep. 3, 1996
Howard US 2002/0197155 Dec. 26, 2002
Seth US 2003/0126800 Jul. 10, 2003

The Examiner made the following rejections:
1. Claims 10-13, 15, 16, and 18 under 35 U.S.C § 103(a) as
unpatentable over Seth in view of Howard and Benoit.
2
Appeal 2007-1852
Application 10/936,925

2. Claim 17 under 35 U.S.C § 103(a) as unpatentable over Seth in
view of Howard, Benoit, and Matarese.
ISSUE
The Examiner contends that it would have been obvious to one of
ordinary skill in the art at the time of the invention to have modified Seth’s
MCrAlY cold spraying process to include the abrasive oxides or abrasive
carbides disclosed by Benoit. Appellants contend that the Examiner has
failed to establish the requisite teaching, suggestion, or motivation for this
modification within the meaning of 35 U.S.C. § 103. The issue for us to
decide is: Has the Examiner identified sufficient factual basis in the prior art
to establish that one of ordinary skill in the art would have been motivated to
combine Seth and Benoit in the manner claimed?
For the reasons discussed below, we answer this question in the
affirmative.
RELEVANT FINDINGS OF FACT
1) The cold gas dynamic spray process is referred to as a "cold
gas" process because the particles are mixed and applied at a
temperature that is well below their melting point. The kinetic
energy of the particles on impact with the target surface, rather
than particle temperature, causes the particles to plastically deform
and bond with the target surface. Therefore, bonding to the HPT
component surface takes place as a solid state process with
insufficient thermal energy to transition the solid powders to
molten droplets. (Specification [0014]).
2) In an exemplary embodiment of the invention, the MCrAlY
powder includes one or more alloys with M being Ni, Co, or
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Appeal 2007-1852
Application 10/936,925

combinations of Ni and Co. Exemplary abrasive materials include
diamond, cubic boron nitride (CBN), and various carbides and
oxides. (Specification [0016]).
3) Seth discloses that it is known in the art to electrodeposit a
coating of hard particles embedded within a matrix on the surface
of certain gas turbine engine components. (Seth [0006]).
4) Seth discloses that known metallic bond coat materials
include MCrAlY and MCrAlRe, where M may be nickel, cobalt or
iron or a mixture thereof. (Seth [0004]).
5) According to Seth, a drawback of the electrodeposition
process, as well as other similar processes employing solutions
such as electroplating or electroless plating, is lack of precise
control in the placement of abrasive particles on the blade tips.
(Seth [0007]).
6) Seth is directed to overcoming the drawbacks of the prior
art by means of a cold spray process which co-deposits hard
particles with a matrix material on the substrate. According to
Seth, the co-deposition of the matrix material and hard particles
may be effected by directing relative quantities of their constituent
particles toward the substrate surface at a velocity sufficiently
high to cause at least some of the matrix material particles to
deform and to bond to the substrate surface while entrapping at
least a portion of the hard particles within the matrix material to
form a matrix composition on the substrate. The matrix
composition forms an abrasive coating on the substrate. (Seth
[0012]).
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Appeal 2007-1852
Application 10/936,925

7) Seth teaches that the matrix material may be a MCrAlY
composition or other suitable compositions provided the matrix
material entraps the hard particles, forms a sufficient bond
strength with the substrate, is resistant to high temperatures and
oxidation, and has sufficient mechanical properties to maintain its
shape on the substrate. (Seth [0010]).
8) The hard particles utilized in Seth’s process include cubic
boron nitride, diamond or other suitable particles having an
appropriate level of hardness. (Seth [0010]). The hard particles
have an average nominal particle diameter of between about 0.005
and 0.010 inches. (Seth [0024]).
9) According to Benoit, a known problem which occurs in the
compressor and turbine sections of gas turbine engines is that the
blade tips come into proximity to the inner wall of the engine case,
rubbing the case wall, or an abradable seal or rubstrip located on
the case wall. (Benoit, col. 1, ll. 17-20).
10) Benoit discloses that a known method of extending the life
of a blade tip is to apply abrasive layers to the blade tip surface.
Methods of applying the abrasive layers include powder
metallurgy techniques, plasma spray techniques, and
electroplating techniques. (Benoit, col. 1, ll. 62-64).
11) Benoit references specific prior art techniques for providing
an abrasive layer on a blade wherein the layer is described as
abrasive particulates entrapped within or encapsulated by the
metal matrix. (See Benoit, col. 1, l. 64 – col. 2, l. 30).
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Appeal 2007-1852
Application 10/936,925

12) Benoit states that a goal of his coating method is to
deliberately place abrasive coating material on the airfoil surfaces
in the corner areas where the leading and trailing edges of the
blade intersect the blade tip surface. (Benoit, col. 2, l. 67 – col. 3,
l. 4).
13) Benoit states that the disclosed coating method is applicable
to known types of compressor and turbine blades such as those
made of a cobalt or nickel superalloy, especially a single crystal
nickel superalloy, titanium, or a titanium alloy. (Benoit, col. 3, l.
65 – col. 4, l. 2).
14) Benoit teaches that the disclosed blade tip abrasive coatings
may be applied to the blade by electroplating, plasma spraying,
powder metallurgy techniques, laser welding, and brazing.
(Benoit, col. 4, ll. 6-10).
15) In an exemplary embodiment, Benoit discloses application
of a coating to a component by electrodepositing nickel, followed
by submersion of the component in a slurry of plating solution and
particulates. (Benoit, col. 6, ll. 10-16).
16) Benoit teaches the use of CBN particulate abrasive, as well
as “the use of other abrasive materials, including but not limited to
alumina and alumina-zirconia” (col. 5, ll. 7-10), in particular
aluminum oxide/zirconium oxide and aluminum oxide (Example
1).
ANALYSIS AND CONCLUSIONS
Appellants’ traversal of the Examiner’s final rejection is based solely
on the Examiner’s proposed combination of Benoit and Seth. In particular,
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Appeal 2007-1852
Application 10/936,925

Appellants contend that the Examiner failed to establish a teaching,
suggestion, or motivation for modifying Seth’s MCrAlY cold spraying
process to include the abrasive oxides or abrasive carbides disclosed by
Benoit. (Br. 3).
Contrary to Appellants’ contention, we find that the facts and reasons
set forth by the Examiner provide a reasonable basis to conclude that one of
ordinary skill in the art would have been motivated to combine the
references in the manner claimed. Accordingly, we affirm the Examiner’s
rejection of claims 10-13 and 15-18 for the reasons well-stated in the
Examiner’s Answer.
A prima facie case of obviousness is established where the Examiner
demonstrates that the invention is nothing more than the predictable result of
a combination of familiar elements according to known methods. See KSR
Int'l Co. v. Teleflex Inc., 127 S.Ct. 1727, 1739, 82 USPQ2d 1385, 1395
(2007). In this case, the Examiner found that both Benoit and Seth are
directed to methods of extending the life of blade tips by applying abrasive
layers to the blade tip surface. (See Findings of Fact 3-6 and 10-12). Both
Benoit and Seth disclose that known methods of applying the abrasive layers
include powder metallurgy techniques, plasma spray techniques, and
electroplating techniques. (Findings of Fact 3 and 10). Benoit teaches that
alumina and alumina-zirconia are suitable abrasives for use in these
conventional processes of applying abrasive layers. (Finding of Fact 16).
Seth discloses that a cold spraying process may be used to apply abrasive
layers and provides improved results over the afore-mentioned conventional
processes. (Finding of Fact 6). Therefore, one of ordinary skill in the art
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Appeal 2007-1852
Application 10/936,925

would reasonably conclude that alumina and alumina-zirconia could be used
as the abrasive in a cold spraying process.
Accordingly, the rejection of claims 10-13, 15, 16, and 18 under
35 U.S.C. § 103(a) as unpatentable over Seth in view of Howard and Benoit
is affirmed. Because Appellants have not presented any additional
substantive arguments with respect to claim 17, the rejection of claim 17
under 35 U.S.C. § 103(a) as unpatentable over Seth in view of Howard,
Benoit, and Matarese is also 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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