Ex Parte Lee

Patent Trial and Appeal Board

Sep 24, 2018

12569354 (P.T.A.B. Sep. 24, 2018)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
12/569,354 09/29/2009
28863 7590 09/26/2018
SHUMAKER & SIEFFERT, P.A.
1625 RADIO DRIVE
SUITE 100
WOODBURY, MN 55125
FIRST NAMED INVENTOR
KangN. Lee
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.
1106-009US01/RCA-10603 8138
EXAMINER
LANGMAN, JONATHAN C
ART UNIT PAPER NUMBER
1784
NOTIFICATION DATE DELIVERY MODE
09/26/2018 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):
pairdocketing@ssiplaw.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte KANG N. LEE
Appeal2017-009645
Application 12/569,354 1
Technology Center 1700
Before ADRIENE LEPIANE HANLON, MICHAEL P. COLAIANNI, and
AVEL YN M. ROSS, Administrative Patent Judges.
HANLON, Administrative Patent Judge.
DECISION ON APPEAL
A. STATEMENT OF THE CASE
The Appellant filed an appeal under 35 U.S.C. § 134(a) from an Examiner's
decision finally rejecting claims 1, 3-14, 16-26, 46, 47, and 50-55. Claims 33 and
3 5--4 7 are also pending but have been withdrawn from consideration. We have
jurisdiction under 35 U.S.C. § 6(b ).
We REVERSE.
1 The real party in interest is said to be Rolls-Royce Corporation. Appeal Brief
dated January 3, 2017 ("App. Br."), at 3.
Appeal2017-009645
Application 12/569,354
According to the Appellant, "[t]he invention relates to coatings for high-
temperature mechanical systems, such as gas turbine engines, and more
particularly to coatings including rare earth silicates." Spec. ,r 2. The coating
comprises, inter alia, a bond layer consisting essentially of a rare earth silicate and
a second phase, wherein the second phase comprises at least one of a silicide, a
glass ceramic, Ab03, Ti02, Hf02, HfSi04, ZrSi04, HfTi04, or ZrTi04.
Representative claim 1 is reproduced below from the Claims Appendix of
the Appeal Brief.
Claim 1. A coating comprising:
a bond layer on a ceramic substrate, the bond layer consisting
essentially of a rare earth silicate and a second phase, the second
phase comprising at least one of a silicide, a glass ceramic, Ab03,
Ti02, Hf02, HfSi04, ZrSi04, HfTi04, or ZrTi04; and
an overlay layer on the bond layer, wherein the bond layer is
between the overlay layer and substrate, and wherein the bond layer
includes up to approximately 30 percent by weight of the second
phase.
App. Br. 25.
Claim 14, the other independent claim on appeal, recites an article
comprising a ceramic substrate, a bond layer on the ceramic substrate, and an
overlay layer deposited on the bond layer, wherein the bond layer consists
essentially of a rare earth silicate and a second phase as recited in claim 1. App.
Br. 27.
The Examiner maintains the following grounds of rejection on appeal: 2
2 The Examiner withdrew the rejection of claims 1, 3-14, 16-26, 46, 4 7, and 50-55
under 35 U.S.C. § 103(a) (pre-AIA) as unpatentable over Spitsberg in view of
Eaton. Examiner's Answer dated May 5, 2017 ("Ans."), at 7-8.
2
Appeal2017-009645
Application 12/569,354
(1) claims 1, 3-10, 13, 14, 16-23, 26, 46, 47, 50, and 51 under 35 U.S.C.
§ I03(a) as unpatentable over Lee3 in view of Saak et al.; 4
(2) claims 11, 12, 24, and 25 under 35 U.S.C. § I03(a) as unpatentable
over Lee in view of Saak, and further in view of Hazel et al.; 5 and
(3) claims 1, 3-14, 16-26, 46, 47, and 50-55 under 35 U.S.C. § I03(a) as
unpatentable over Spitsberg et al. 6 in view of Eaton et al.,7 Sun et al.,8 and
Lee 151. 9
B. DISCUSSION
1. Rejections (1) and (2)
The Examiner finds Lee teaches an environmental barrier coating on a
ceramic substrate, wherein the environmental barrier coating comprises a bond
coat. Final Act. 2. 10 The Examiner directs attention to Lee Figure 10, reproduced
below in relevant part. Final Act. 3.
r
l
{b)
Topcoat
l 0¢lonat bt'lrK:I ooat r Substrat,a
(c)
r-,~~ .......... ~-~~-
t Top Coat i ;,.,~·;.,.,.,: ...... ~·-)o'"IYY,""""'-•'1;".,,..,..7¥"""
I CB.+.TC •.
t''"'' ___ "'"""''"~""'"'''""""'''""==,.:
: Bond coat •
~ _Optional bond coot ___ ••
I .
1 Sot~~'trata
[
~
3 WO 2007 /098152 A2, published August 30, 2007 ("Lee").
4 US 2006/0014029 Al, published January 19, 2006 ("Saak").
5 US 2006/0280953 Al, published December 14, 2006 ("Hazel").
6 US 2006/0280954 Al, published December 14, 2006 ("Spitsberg").
7 US 2004/0234783 Al, published November 25, 2004 ("Eaton").
8 US 2003/0113553 Al, published June 19, 2003 ("Sun").
9 US 6,759,151 Bl, issued July 6, 2004 ("Lee 151").
1° Final Office Action dated June 16, 2016.
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Appeal2017-009645
Application 12/569,354
Lee Figure 10 illustrates various embodiments incorporating
a chemical barrier into multilayer environmental barrier
coating systems.
Referring to Lee Figure 10( c ), the Examiner finds that the CB ( chemical
barrier)+ TC (top coat) layer, which is disposed between a substrate and an
overlay layer, 11 corresponds to the claimed bond layer. Final Act. 3. The
Examiner finds the top coat may be a rare earth silicate (e.g., Re2Sh07) 12 and the
chemical barrier material may be HfSi04. 13 Final Act. 3.
Lee discloses that "[ c ]ompositional grading can be created in ... CB+ TC."
Lee Fig. 10. Thus, the Examiner finds that Lee teaches a compositionally graded
mechanical mixture of Re2Sh07 (TC) and HfSi04 (CB), wherein a first phase is
Re2Si207 and a second phase is HfSi04. Final Act. 3.
Although Lee teaches that the CB+ TC layer may be compositionally graded,
the Examiner finds that Lee does not disclose the specifics of the layer, e.g., the
amount of the second phase in the layer. Final Act. 3. Therefore, the Examiner
turns to Saak.
The Examiner finds that Saak, like Lee, discloses protective coatings for
turbine components. The Examiner finds Saak discloses that "transition layers
may be used to improve compatibility between two coatings, by providing a layer
that is compositionally graded from one component of the underlying layer to
another component of the overlaying layer." Final Act. 3 (citing Saak ,r,r 14--15).
The Examiner concludes that it would have been obvious to one of ordinary
skill in the art to compositionally grade Lee's transition layer (i.e., CB+ TC layer)
11 The Examiner finds that the "Top Coat" in Lee Figure 10( c) reads on the
claimed overlay layer. Final Act. 4.
12 See Lee Figure 9.
13 See Lee Figure 9.
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Application 12/569,354
"as this is a known technique for blending layers to match CTE' s [ coefficient of
thermal expansion] and improve coating performance." Final Act. 4. The
Examiner finds that the top 30% and top 20% of Lee's modified transition layer
would have the same composition as claimed, i.e., a coating with 30 wt.% and 20
wt.%, respectively, ofHfSi04 (as a second phase) and 70 wt.% and 80 wt.%,
respectively, of rare earth disilicate (Re2Sb07 ). Final Act. 4.
The Appellant argues, inter alia, that the Examiner has failed to establish
that a compositionally graded layer including a rare earth silicate and HfSi04 (i.e.,
CB + TC layer) constitutes a layer including a first phase and a second phase as
recited in the claims on appeal. App. Br. 5. In that regard, the Appellant argues
that "Lee does not describe that a compositionally graded layer of the TC and CB
may include the TC as a first phase and the CB as a second phase in the same
layer." App. Br. 5.
The Examiner explains:
[B]y compositionally grading one of ordinary skill in the art would
add the two materials and blend. Since Lee[] does not teach solid
solutions of the mixtures, it would be understood and expected that
the components of the chemical barrier layer and the top coat would
exist as distinct phases.
Adv. Act. 2. 14
The Appellant argues:
[T]he failure of Lee to describe solid solutions of the mixtures does
not establish that it would be understood and expected that the
components of the chemical barrier layer and the top coat would exist
as distinct phases. Indeed, even assuming, arguendo, that Lee fails to
describe "solid solutions of the mixtures," the Examiner has provided
no basis for the conclusion that such a failure would result in one of
skill in the art understanding that a compositionally graded layer of
14 Advisory Action dated August 23, 2016.
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Application 12/569,354
the TC and CB may include the TC as a first phase and the CB as a
second phase in the same layer.
App. Br. 7.
In response, the Examiner directs attention to the micrograph of Lee Figure
12 and finds that HfSi04 is added to a coating by mechanical mixing. Ans. 8
( citing Lee 18, 11. 5---6). The Examiner finds that:
[W]hen HfSi04 [sic] is incorporated by mechanical mixing it remains
as a distinct phase in the layer. While [Lee Figure 12] is not showing
a depiction of a CB and a TC layer, this none the less [sic] supports
the offices [sic] position that the additives are intended to remain as
separate compounds and/or phases and that no examples in Lee teach
a solid solution mixture.
Ans. 8-9 ( emphasis added).
To the extent that Lee does not disclose solid solutions of a mixture of a rare
earth silicate (e.g., Re2Sb07) and HfSi04, Lee, likewise, does not expressly
disclose that the CB+ TC layer includes HfSi04 as a second phase. In contrast,
Lee expressly describes a mullite bond coat ( corresponding to the "Bond coat" in
Figure lO(c)) as including a "second phase" oxide. See, e.g., Lee 25, 11. 2-3. Lee
Figure 12 is said to depict HfSi04 in that bond coat (mullite + Si). Lee 5.
We recognize that Lee discloses that a chemical barrier can be mechanically
mixed with a top coat. See Lee 17, 11. 18-20 ( disclosing that "[ t ]he chemical
barrier can be incorporated [into multilayer environmental barrier coating systems]
as a discreet layer, a graded layer, a mechanical mixture with the bond coat and/or
the top coat, alternating multilayers with the bond coat and/or the top coat, or
combinations thereof'). However, the Examiner does not discuss how the mixture
is applied to the substrate in Lee Figure 10( c) to form the CB + TC layer15 and why
15 Lee discloses that "[t]he environmental barrier coatings contemplated herein
may be applied by any conventional method, such as plasma spraying, EB-PVD,
slurry-based processes, CVD, PVD, etc." Spec. 8, 11. 1-3.
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Application 12/569,354
one of ordinary skill in the art would have expected a second phase of HfSi04 to
exist after the mixture is applied.
Based on the foregoing, the Examiner has failed to establish, in the first
instance, that the claimed bond layer, consisting essentially of a rare earth silicate
and a second phase, would have been obvious to one of ordinary skill in the art
based on the combination of Lee and Saak. See In re Oetiker, 977 F.2d 1443, 1445
(Fed. Cir. 1992) (examiner bears the initial burden of presenting a prima facie case
of unpatentability). Therefore, the obviousness rejection of claims 1, 3-10, 13, 14,
16-23, 26, 46, 47, 50, and 51 is not sustained.
The Examiner does not rely on Hazel to cure the deficiency in the rejection
of claim 1 identified above. See Final Act. 4--5. Therefore, the obviousness
rejection of claims 11, 12, 24, and 25 also is not sustained.
2. Rejection (3)
Spitsberg teaches a protective coating for a turbine component comprising
silicon-containing substrate 30, higher metal silicate coating 66, outer corrosion
resistant sealant layer 74, and overlaying thermal barrier coating 80. 16 See
Spitsberg Fig. 2; 17 see also Final Act. 7. The Examiner finds that the higher metal
silicate in coating 66 reads on the claimed rare earth disilicate materials. Final Act.
7. The Examiner, however, finds Spitsberg does not disclose that the higher metal
silicate coating includes a second phase as recited in claim 1. Final Act. 7.
The Examiner finds Eaton teaches that rare earth disilicate compositions
must be carefully chosen to closely match the CTE of a substrate. Final Act. 7. To
illustrate that point, the Examiner finds Eaton discloses a silicon nitride substrate
16 The Examiner finds layers 74 and 80 correspond to the claimed overlay layer.
Final Act. 8.
17 Spitsberg discloses that layers 50 and 58 are optional. Spitsberg ,r,r 40, 41.
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Application 12/569,354
(i.e., a silicon-containing ceramic substrate within the scope of Spitsberg's silicon-
containing substrate (Spitsberg ,r 29)) having a CTE of around 3.5 and a yttrium
disilicate coating "deposited on the substrate because it has a CTE of 4 which
closely matches the underlying silicon based substrate." Final Act. 7-8.
Similarly, Sun discloses that "[i]t is important for the integrity of the final
article to maintain a compatibility between the coefficient of thermal expansion
(CTE) of the silicon containing substrate and adjacent layers and between adjacent
layers themselves." Sun ,r 3; see also Final Act. 8. Sun discloses a CTE tailoring
additive comprising NbOx, such as Nb20s, and an oxide, such as Ab03. Sun ,r,r 6,
9. The Examiner finds the additives are added in a desired amount "to tailor a
coating to have a CTE that closely matches the CTE of the substrate." Final Act.
8. Because Sun's additive adjusts the CTE of an existing coating, the Examiner
finds that "one would understand that these additives remain as distinct phases and
do not dissolve into the base line coating or form a solid solution with the base line
coating." Ans. 14.
The Examiner finds Lee 151 teaches that the CTE of rare earth silicates
increases as the ionic radius increases. Final Act. 8.
The Examiner concludes that it would have been obvious to one of ordinary
skill in the art to add a second phase ofNb20s and Ah03 to Spitsberg's rare earth
disilicate coating "to better match the CTE of the coating to the CTE of the
substrate in order to ensure that the coatings will not break down at the interfaces
due to non compatibility." 18 Final Act. 8.
18 As for the claimed amount of the second phase, the Examiner finds:
The claimed amounts would have been obvious to one of ordinary
skill in the art at the time of the present invention dependent upon the
low CTE material chosen (Al203), the CTE of the Substrate and the
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Application 12/569,354
The Appellant argues, inter alia, that the Examiner has failed to establish
that a mismatch would have existed between Spitsberg's substrate 30 and higher
metal silicate coating 66 that would have led one skilled in the art to modify
coating 66 to more closely match the CTE of substrate 30. App. Br. 19.
The Appellant's argument is persuasive of reversible error. The Examiner
does not direct us to any portion of Spitsberg disclosing that a CTE mismatch
would have been expected to exist between substrate 30 and coating 66. Rather,
the Examiner makes certain selections that arguably would result in a CTE
mismatch between the substrate and the higher metal silicate. More specifically,
the Examiner finds that typical turbine components include materials with a CTE
of 3.5, 19 and Y2Sb07 (i.e., a higher metal silicate) has a CTE of 4.0, which is said
to closely match the CTE of the turbine component. Adv. Act. 7; Final Act. 7-8.
The Examiner finds Spitsberg discloses that other higher metal silicates, such as
ytterbium silicate, are also suitable for coating 66. Spitsberg ,r 26; see also Adv.
Act. 7. The Examiner finds that Lee 151 teaches that the CTE increases as the
ionic radius increases ( e.g., when ytterbium is selected over yttrium as the rare
earth in the higher metal silicate20). Adv. Act. 7. Thus, when ytterbium silicate is
selected for Spitsberg's coating 66 and a silicon-based ceramic matrix composite
type of rare earth silicate. These are all easily optimizable conditions
well within the grasp of a routineer in the art.
Final Act. 8; see also Ans. 15.
The Appellant, however, "does not agree with the Examiner's conclusion
regarding the amount ... of second phase as being an easily optimizable
condition[] well within the grasp of a routineer in the art." App. Br. 20. It is not
necessary to address the Appellant's argument in view of our reversal on other
grounds.
19 The Examiner apparently bases this finding on a previous finding that Eaton
discloses that silicon nitride substrates have a CTE of around 3.5. Final Act. 7.
20 The Examiner does not identify the CTE of ytterbium silicate.
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Application 12/569,354
(CMC), e.g., silicon nitride, is selected for substrate 30, the Examiner finds that
one of ordinary skill in the art would have understood that Sun's additives would
be useful to lower the CTE of the higher metal silicate to match the CTE of the
substrate. Adv. Act. 7.
Spitsberg's substrate, however, is not limited to silicon nitride but rather
may be "any silicon-containing-substrate." Spitsberg ,r 29. Spitsberg also
discloses that it is important for an environmental barrier coating system, which
comprises coating 66, 21 to include a CTE compatible or closely matched with the
silicon-containing substrate. Spitsberg ,r 4. Thus, on this record, the Examiner has
failed to show, in the first instance, that one of ordinary skill in the art would have
selected ytterbium silicate to coat a silicon nitride substrate, arguably resulting in a
CTE mismatch, based on the teachings in Spitsberg. See Oetiker, 977 F .2d at 1445
( examiner bears the initial burden of presenting a prima facie case of
unpatentability). In view of that deficiency in the obviousness rejection on appeal,
there would have been no reason to modify Spitsberg' s higher metal silicate
coating with Sun's tailoring additive, which the Examiner finds corresponds to the
second phase recited in claim 1. See Ans. 14.
For the reasons set forth above, the obviousness rejection of claims 1, 3-14,
16-26, 46, 47, and 50-55 is not sustained.
C. DECISION
The Examiner's decision is reversed.
REVERSED
21 See Spitsberg ,r 41.
10