Ex Parte Kebbede et al

Patent Trial and Appeal Board

Aug 4, 2016

12433090 (P.T.A.B. Aug. 4, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
12/433,090 0413012009
6147 7590 08/08/2016
GENERAL ELECTRIC COMPANY
GLOBAL RESEARCH
ONE RESEARCH CIRCLE
BLDG. Kl-3A59
NISKAYUNA, NY 12309
FIRST NAMED INVENTOR
Anteneh Kebbede
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www .uspto.gov
ATTORNEY DOCKET NO. CONFIRMATION NO.
153001-1 8384
EXAMINER
TUROCY, DAVID P
ART UNIT PAPER NUMBER
1718
NOTIFICATION DATE DELIVERY MODE
08/08/2016 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address( es):
haeckl@ge.com
gpo.mail@ge.com
Lori.e.rooney@ge.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte ANTENEH KEBBEDE, KRISHAN LUTHRA, and
GREGORY CORMAN
Appeal2014-008499
Application 12/433,090
Technology Center 1700
Before BRADLEY R. GARRIS, CHRISTOPHER L. OGDEN, and
JULIA HEANEY, Administrative Patent Judges.
HEANEY, Administrative Patent Judge.
DECISION ON APPEAL
Appellants 1 request review pursuant to 35 U.S.C. § 134(a) of a
decision of the Examiner finally rejecting claims 1-13 and 15-25 of
Application 12/433,090. We have jurisdiction under 35 U.S.C. § 6(b). We
affirm.
1 Appellants identify the real party in interest as General Electric Company.
App. Br. 2.
Appeal2014-008499
Application 12/433,090
BACKGROUND
The subject matter on appeal relates to a process for producing a
ceramic matrix composite ("CMC") article that contains a ceramic
reinforcement material in a solid ceramic matrix. The process involves
infiltrating elemental silicon, silicon boron alloy, or a combination of the
two into a porous, ceramic reinforced preform by heating, then cooling the
infiltrated preform to produce a preliminary composite structure that
contains a ceramic phase (e.g., SiC), as well as elemental silicon or silicon
alloy as a non-ceramic phase. App. Br. 3-4; Spec. 8-9. Through further
processing steps, the elemental silicon or silicon alloy is at least partially
removed from the matrix of the composite structure and converted to a
nonreactive silicon compound, so that the CMC article can withstand
temperatures above 1405 °C.
Claims 1 and 7 are illustrative and reproduced below:
1. A process for producing a ceramic matrix composite
article, the process comprising:
producing a ceramic matrix composite body containing a
ceramic reinforcement material in a solid matrix that
comprises a ceramic matrix material by
infiltrating any one of elemental silicon, or boron-
containing inorganic material consisting of silicon
boron alloy, or a combination thereof into a porous
preform comprising a ceramic reinforcement material to
form an infiltrated preform
and then cooling the infiltrated preform to produce a
ceramic matrix composite body
wherein the boron-containing inorganic material
added to the porous preform by infiltration consists
of silicon boron alloy and
wherein the ceramic matrix composite body is free
of molybdenum silicide; and then
2
Appeal2014-008499
Application 12/433,090
treating the ceramic matrix composite body by at least
partially removing solid elemental silicon and/or silicon
boron alloy from the solid matrix and
optionally reacting a remainder of the solid elemental
silicon and/or silicon boron alloy in the solid matrix to
form a refractory material,
the solid elemental silicon and/or silicon boron alloy
being sufficiently removed from the ceramic matrix
composite body to enable the ceramic matrix composite
article to withstand temperatures above 1405°C.
7. The process according to claim 1,
wherein the solid elemental silicon and/or silicon boron
alloy is at least partially removed from the solid matrix by
melting the solid elemental silicon and/or boron silicon
alloy and
drawing the molten elemental silicon and/or silicon
boron alloy from the body.
Appeal Br. 49--51 (Claims App'x) (some paragraphing and indentation
added).
REFERENCES
The Examiner relied upon the following prior art in rejecting the
claims on appeal:
Corman
("Corman '15 8")
Suyama, et al.
("Suyama")
Grossman
("Grossman")
Sonuparlak, et al.
("Sonuparlak")
US 6,403,158 Bl Jun. 11,2002
us 5,990,025 Nov. 23, 1999
us 5,571,758 Nov. 5, 1996
us 5,164,233 Nov. 17, 1992
3
Appeal2014-008499
Application 12/433,090
Corman, et al.
("Corman '762")
Kameda, et al.
("Kameda")
US 2007 /0092762 Al Apr. 26, 2007
US 6,235,379 Bl May 22, 2001
G.S. Corman & K.L. Luthra, Silicon Melt Infiltrated Ceramic
Composites, in Handbook of Ceramic Composites 99 (N arottam
P. Bansal ed., 2005) ("Silicon Melt")
Rosenloecher
("Rosenloecher")
US 2003/0178733 Al
THE REJECTIONS
Sep.25,2003
1. Claims 1-2, 4, 11-12, and 25 are rejected under 35 U.S.C.
§ 102(b) as anticipated by Corman '158. 2
2. Claims 1-6, 11, 13, 15-17, 21, and 23 are rejected under
35 U.S.C. § 103(a) as being obvious over Suyama.
3. Claims 7-10 are rejected under 35 U.S.C. § 103(a) as
being obvious over Suyama in view of Grossman.
4. Claim 12 is rejected under 35 U.S.C. § 103(a) as being
obvious over Suyama in view of Sonuparlak.
5. Claims 18-19 are rejected under 35 U.S.C. § 103(a) as
being obvious over Suyama in view of Corman '7 62.
2 In the Answer, the Examiner withdrew a rejection of claims 9-10 under 35
U.S.C. § 102(b) as anticipated by Corman '158. Ans. 13. The Examiner
also withdrew a rejection of claims 1-13 and 15-25 under 35 U.S.C. § 112,
first paragraph, for failing to comply with the written description
requirement. Id.
4
Appeal2014-008499
Application 12/433,090
6. Claims 18-20 are rejected under 35 U.S.C. § 103(a) as
being obvious over Suyama in view of Kameda.
7. Claims 18-22 are rejected under 35 U.S.C. § 103(a) as
being obvious over Suyama in view of Silicon Melt.
8. Claims 1-6, 11, 13, 15-17, 21, and 23-24 are rejected
under 35 U.S.C. § 103(a) as being obvious over Suyama in
view of Rosenloecher.
9. Claims 7-10 are rejected under 35 U.S.C. § 103(a) as
being obvious over Suyama and Rosenloecher in view of
Grossman.
10. Claims 12 and 25 are rejected under 35 U.S.C. § 103(a) as
being obvious over Suyama and Rosenloecher in view of
Sonuparlak.
11. Claims 18-19 are rejected under 35 U.S.C. § 103(a) as
being obvious over Suyama and Rosenloecher in view of
Corman '762.
12. Claims 18-20 are rejected under 35 U.S.C. § 103(a) as
being obvious over Suyama and Rosenloecher in view of
Kameda.
13. Claims 18-22 are rejected under 35 U.S.C. § 103(a) as
being obvious over Suyama and Rosenloecher in view of
Silicon Melt.
DISCUSSION
Appellants present arguments by grouping the claims into nine
groups. App. Br. 6. Having carefully reviewed Appellants' extensive briefs,
we determine that Appellants do not present distinct arguments for each of
5
Appeal2014-008499
Application 12/433,090
the nine groups, but rather focus their arguments on limitations of
independent claim 1 and present separate arguments for three groups of
dependent claims, i.e., claims 7-10, 12, and 18-21. 3 Therefore, we limit our
discussion to claim 1 and three groups of dependent claims; all other
dependent claims stand or fall with claim 1. 37 C.F.R. § 41.37(c)(l)(iv).
Further, having considered the evidence presented in this Appeal and each of
Appellants' contentions, we are not persuaded that Appellants identify
reversible error. Therefore, we affirm the rejections for the reasons
expressed by the Examiner in the Final Action and the Answer. We add the
following primarily for emphasis.
Anticipation Rejection
Appellants' arguments against the anticipation rejection focus on the
claim limitation "at least partially removing" solid elemental silicon and/or
silicon boron alloy from the matrix. Claims Appx., claims 1 and 25.
Appellants contend that Corman '158 does not disclose actual removal of
silicon or silicon boron alloy with sufficient specificity to support
anticipation. App. Br. 7. Specifically, Appellants argue that the statements
in Corman '158 that boron silicide residue "must be removed by machining"
(Corman '158 1:42) and excess silicon "requires machining" (id. 1:45) are
too vague and ambiguous because they do not disclose that machining
actually occurred, and "could be interpreted as a description of the condition
of the article rather than machining by Corman' 158." App. Br. 8.
Appellants' arguments are not persuasive of reversible error. The
Examiner finds that Corman '15 8 unequivocally discloses removing excess
3 Appellants present no distinct arguments for patentability of independent
claims 22 and 25.
6
Appeal2014-008499
Application 12/433,090
silicon or silicon boron alloy by machining; this meets the requirement in
claims 1 and 25 of "at least partially removing." Ans. 15. Appellants have
not offered evidence that a person of ordinary skill in the art would find
Corman's disclosure of machining as vague and ambiguous. App. Br. 6-10;
Reply Br. 2--4. In the absence of any such evidence, we are not persuaded
by Appellants' arguments, and conclude that a preponderance of the
evidence supports the Examiner's findings. We therefore affirm Rejection
1.
Obviousness Rejections
Rejections 2 and 8
Suyama discloses a CMC combining ceramic fibers with a silicon
carbide (SiC) matrix, for high-temperature applications such as a gas turbine
engine. Suyama col. 1, 11. 5-12, 34--3 7. Suyama specifically teaches that
"free Si disadvantageously degrades high-temperature strength" of CM Cs
because free silicon has a relatively low melting point, i.e. around 1410°C.
Id. col. 2, 11. 25-27. Suyama thus discloses reducing the amount of free
silicon in the CMC by substituting silicon in the matrix with molybdenum
(Mo) based compounds "having a general formula of Mo--Si-X," such as
molybdenum silicide (MoSb). Id. col. 2, 11. 40-53; col. 3, 11. 9-13.
Suyama's examples describe producing a CMC by infiltrating a molten Si-
Mo alloy into a preform woven from SiC continuous fibers coated with
boron nitride, to form a matrix consisting of SiC, MoSi2, and free silicon
(Example 1, col 8, 1. 57---col. 9, 1. 28), then heating the CMC to a temperature
of at least 1600°C to remove free silicon (Example 2). In Comparative
Example 1, only free silicon is infiltrated into the preform, and there is no
further heating step to remove the free silicon. Suyama col. 10, 11. 20-27.
Table 1 shows the results of bending strength tests at room temperature and
7
Appeal2014-008499
Application 12/433,090
1600°C on samples prepared according to Examples 1 and 2 and
Comparative Example 1, among others. Id., col. 11. The Examiner
determines that in view of the lower strength of Comparative Example 1 at
1600°C, a person of ordinary skill in the art would have found it obvious to
at least partially remove free silicon in the CMC process in order to achieve
better high temperature strength. Ans. 20.
Appellants argue Suyama teaches that molybdenum silicide is critical
for high temperature strength of its CMC, and thus would not motivate a
person of ordinary skill in the art to make a CMC "free of molybdenum
silicide" as recited in claims 1. App. Br. 11-13. Appellants further argue
that removing molybdenum silicide from Suyama's composite would change
Suyama's principle of operation, and that Suyama teaches against omitting
molybdenum silicide. Id. at 13.
We have reviewed each of Appellants' arguments, and find that a
preponderance of the evidence supports the Examiner's determination of
obviousness. As the Examiner notes, Suyama' s examples teach that removal
of elemental silicon is critical-not the presence of MoSi2. Ans. 21, 25.
Further, although the results for Suyama's Comparative Example 1 that is
free ofMoSi2 (as recited in claim 1) are somewhat inferior, it nonetheless
has some high temperature strength, i.e., it has an initial cracking strength of
50(F) at 1600°C (which is higher than the temperature of 1405°C recited in
claim 1). Suyama Table 1. These results support the Examiner's
determination that a person of ordinary skill in the art would have expected
predictable results in removing non-reacted silicon from a matrix that also is
free of MoSi2. Ans. 4. Moreover, somewhat inferior results do not
necessarily mean that Suyama's principle of operation would have been
changed by removal of MoSi2. Finally, although Suyama teaches using
8
Appeal2014-008499
Application 12/433,090
MoSb to provide increased high temperature strength, as the Examiner
notes, Suyama attributes strength in the high-temperature range to the
"density ratio of the matrix" and low percentage of free silicon, not to the
presence of MoSi2 . Id. (citing Suyama col. 11, 11. 34--40). 4 Therefore, a
preponderance of the evidence supports the Examiner's conclusion of
obviousness in view of Suyama, and we affirm Rejection 2.
Rosenloecher discloses infiltration of porous carbon composites to
form CMCs, particularly with SiC in the matrix. Rosenloecher i-f 1.
Rosenloecher specifically teaches that composites with metal carbide
matrices can be produced by melt infiltration using "[b ]oth the semimetals
silicon and boron" as well as iron, nickel, titanium, zirconium, vanadium,
chromium, molybdenum, and tungsten. Rosenloecher i-f 10. Additionally,
Rosenloecher describes the use of wicks, or porous bodies such as carbon
felts, "which draw in liquids by capillary action and can release them at
another point." Rosenloecher i-f 13. The Examiner determines that in view
of Rosenloecher, it would have been obvious to a person of ordinary skill in
the art to use a silicon-boron alloy as an infiltrate as a substitute for Si-Mo
infiltrates as taught by Suyama. Final Act. 12-13.
Appellants argue that Rosenloecher' s broad disclosure of metal
infiltrates (Rosenloecher i-f 10) is not sufficient evidence of predictability or
suitability of a Si-B alloy as a substitute for Si-Mo infiltrates, especially in
view of the comparative examples in Suyama. App. Br. 28, 32-34.
Appellants' argument is not persuasive of reversible error. As the Examiner
correctly finds, Rosenloecher in fact specifically identifies silicon and boron
as suitable semimetal infiltrates. Ans. 48 (citing Rosenloecher i-f 10).
4 Appellants do not respond to this finding in the Reply Brief.
9
Appeal2014-008499
Application 12/433,090
Further, the fact that a reference "discloses a multitude of effective
combinations does not render any particular formulation less obvious."
Merck & Co., Inc. v. Biocraft Labs, 874 F.2d 804, 808 (Fed. Cir. 1989).
Therefore, a preponderance of the evidence supports the Examiner's
conclusion that even if Suyama alone would not have rendered claim 1
obvious, it would have been obvious in view of the combination of Suyama
and Rosenloecher to substitute a Si-B alloy for molybdenum silicide as a
molten infiltrate in preparation of a high temperature strength CMC. Final
Act. 12-13. We therefore affirm Rejection 8.
Rejections 3 and 9
Rejections 3 and 9 are directed to claims 7-10, which relate to
specific techniques for the step of removing elemental silicon or silicon
boron alloy from the matrix, as recited in claim 1.
Grossman discloses the use of a wick for infiltration of silicon-boron
alloy into a CMC preform. Grossman col. 2, 11. 12-6; col. 4, 11. 24--26.
Grossman further teaches that "the wick is preferably carbon in the form of
carbon fibers" and that the fibers can be "tows of fine fibers in woven or
unwoven form." Grossman col. 4, 11. 17-9. The Examiner determines that it
would have been obvious to use Grossman's carbon fiber mat in Suyama's
process, in order to wick silicon away from the preform and remove
unreacted silicon with a reasonable expectation of success. Final. Act. 9.
The Examiner further determines that using Grossman's carbon fiber mat in
the combined disclosures of Suyama and Rosenloecher would have been
obvious, for the reasons set forth above. Final Act. 13.
Appellants argue that Grossman fails to provide any teaching or
suggestion that would motivate a person skilled in the art to substitute
silicon boron alloy for molybdenum silicide (App. Br. 18-19). Appellants
10
Appeal2014-008499
Application 12/433,090
further argue that using Grossman's wick to draw molten silicon away from
the composite in Suyama's process changes Grossman's principle of
operation because Grossman uses a wick to draw silicon toward a preform.
App. Br. 19-20.
Appellants' argument does not persuade us of reversible error because
it fails to take into consideration the level of ordinary skill in the art at the
time of the invention. As the Examiner correctly finds, a person of ordinary
skill would understand from Grossman's entire disclosure that a wick can be
used to draw molten silicon away from a preform, and not only toward it.
Ans. 31. Obviousness does not require an express suggestion of the claimed
invention in any or all of the references, but rather is based on what the
references taken collectively would suggest to a person of ordinary skill in
the art presumed to be familiar with them. In re Rosselet, 34 7 F .2d 84 7, 850
( CCP A 1965). In addition, Appellants' argument that the combination of
Suyama and Grossman changes Grossman's principle of operation is not
relevant to the rejections because the Examiner proposes modifying Suyama
not Grossman. Therefore, we affirm Rejections 3 and 9.
Rejections 4 and 10
Rejections 4 and 10 are directed at claims 12 and 25. Claim 12 recites
removing elemental silicon or silicon boron alloy from the matrix by
etching; Appellants do not present distinct argument for claim 25.
Sonuparlak discloses that a CMC composite may be treated by etching
"to remove at least a portion of the metallic constituent of the ceramic
composite substrate at the surface of the substrate." Sonuparlak col. 15, 11.
54---6. The Examiner determines that it would have been obvious to a person
of ordinary skill in the art to modify Suyama's process by using
Sonuparlak's method for removing metal by vaporization or etching, to
11
Appeal2014-008499
Application 12/433,090
remove silicon from the surface of the preform, because Sonuparlak
discloses advantages and predictable results associated with etching and
vaporization. Final Act. 9 (citing Sonuparlak col. 15, 11. 54--6; col. 16, 1. 44--
col. 17, 1. 3). The Examiner further determines that using Sonuparlak's
method in the combined disclosure of Suyama and Rosenloecher would have
been obvious, for the reasons set forth above. Final Act. 13-14.
Appellants argue that the Examiner does not point to "any teaching or
suggestion in Sonuparlak that would motivate one skilled in the art either to
omit molybdenum silicide or substitute silicon boron alloy." App. Br. 21,
40. In addition, Appellants argue that the failure of Sonuparlak to disclose
predictable results from etching Suyama's composites "would lead one
skilled in the art away from such methods in order to avoid any detrimental
effect." App. Br. 21-22, 40.
Appellants' arguments are not persuasive of reversible error. Arguing
against individual references cannot overcome a rejection based on a
combination of references. In re Keller, 642 F.2d 413 (CCPA 1981).
Further, the Examiner has explained that Sonuparlak discloses advantages
and predictable results associated with etching, and Appellants do not offer
technical reasoning or evidence to the contrary. Accordingly, we conclude
the preponderance of the evidence supports the Examiner's findings and
conclusions as to claims 12 and 25 and affirm Rejections 4 and 10.
Rejections 5-7 and 11-13
These rejections are directed at claims 18-21, which include
limitations relating to coating the ceramic reinforcement material with a
release agent, and retaining the release agent to allow controlled slip
between the ceramic reinforcement material and the matrix. Corman '7 62
discloses a method of protecting the outer surface of CM Cs with a protective
12
Appeal2014-008499
Application 12/433,090
layer. Corman '7 62 i-f 19. Specifically, "fibers 15 are preferably coated with
materials to impart certain desired properties to the CMC substrate 20, such
as a carbon or boron nitride interface layer (not shown) over which a SiC or
SbN4 coating (not shown) may be deposited to protect the fibers 15 during
melt infiltration." Id. i-f 20. The Examiner determines that it would have
been obvious to combine Suyama with the disclosure in Corman '7 62 of
depositing boron nitride or carbon coating onto fibers for a ceramic matrix
as well as depositing a barrier layer, to impart desired properties known to
those of ordinary skill in the art, as a predictable use of prior art elements
according to their established functions. Final Act. 9.
Kameda discloses a method "for coating a sliding layer comprising
boron nitride (BN) and the like is known in the art" and allows fibers "to
slide against the matrix by weakening the bonding between the fiber and
matrix." Kameda col. 1, 1. 65---col. 2, 1. 2. This provides improved CMC
properties including high tenacity, reliability, and heat resistance and
strength at high temperatures. Id. col. 1, 11. 21---65. Kameda further
discloses that during sintering "the reactivity of the molten Si to be
impregnated is so high that it readily reacts with the sliding layer or fiber
itself'. Id. col. 2, 11. 9-11. Final Act. 10. The Examiner determines it
would have been obvious to a person of ordinary skill in the art to provide
Kameda's boron nitride barrier layer thick enough to maintain boron nitride
on the fibers of the matrix after reactions with the infiltrated silicon because
it is a known and suitable technique with predictable results. Id. Final Act.
10.
Silicon Melt discloses that most CMC coatings are "applied to fibers
to serve as the fiber-matrix interface." Silicon Melt at 101. Moreover, the
coatings are "necessary to prevent chemical attack of the fibers during
13
Appeal2014-008499
Application 12/433,090
processing and to provide for a weak mechanical interface between the fiber
and matrix for enhanced toughness and graceful failure." Id. Silicon Melt
teaches that such coatings can include BN, although BN is subject to
degradation by molten silicon, and, so, over coatings may be used to protect
the BN layer, including SiC or ShN4. Id. Based on Silicon Melt's
disclosure of a protective coating on boron nitride and such layer reacting
with silicon infiltrate, the Examiner determines it would have been obvious
to provide an appropriate thickness of coating such that boron nitride is
maintained on the fibers following the reaction because it is a known and
suitable technique with predictable results. Final Act. 11. In addition, the
Examiner determines that Suyama discloses ceramic matrix materials are
exposed to temperatures higher than 1405°C and Silicon Melt discloses a
gas turbine, so that it would have been obvious to use Suyama's materials in
a gas turbine as recited in claim 21, with a reasonable expectation of success.
Id.
Appellants argue that none of the references would motivate a person
of ordinary skill in the art to substitute molybdenum silicide with silicon
boron alloy. App. Br. 22, 24, 42, 44. In addition, Appellants argue that the
references fail to disclose a teaching or motivation suggesting that the
combination of references would yield predictable results. App. Br. 22, 24,
42, 43, 45. Appellants argue further that Suyama teaches away from the
claimed invention. App. Br. 23, 25, 42, 43, 45.
Appellants' arguments fail to show harmful error in these obviousness
rejections. As set forth above, the Examiner provided a rational
underpinning to support the legal conclusion of obviousness. Moreover,
Appellants' argument are unsupported by evidence; for example, contrary to
Appellants' argument, Suyama in fact discloses a boron nitride coating on its
14
Appeal2014-008499
Application 12/433,090
SiC fibers. Suyama Example 1. In view of the prima facie case of
unpatentability established by the Examiner and the absence of evidence in
rebuttal offered by Appellants, we affirm Rejections 5-7 and 11-13.
CONCLUSION
We affirm the rejections of claims 1-13 and 15-25.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(l )(iv).
AFFIRMED
15