Ex Parte LeeDownload PDFPatent Trial and Appeal BoardSep 24, 201812569354 (P.T.A.B. Sep. 24, 2018) Copy Citation 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 Claims 33 and 3 5--4 7 are also pending but have been withdrawn from consideration.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. 3 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. 4 Appeal2017-009645 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. 5 Appeal2017-009645 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. 6 Appeal2017-009645 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. 7 Appeal2017-009645 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 8 Appeal2017-009645 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. 9 Appeal2017-009645 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 Copy with citationCopy as parenthetical citation