Ex Parte Berczik et alDownload PDFPatent Trial and Appeal BoardOct 29, 201312751091 (P.T.A.B. Oct. 29, 2013) Copy Citation UNITED STATES PATENT AND TRADEMARKOFFICE 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 APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 12/751,091 03/31/2010 Douglas M. Berczik 085.11464-US-AA(05-141-2) 9996 52237 7590 10/29/2013 BACHMAN & LAPOINTE, P.C. c/o CPA Global P.O. Box 52050 Minneapolis, MN 55402 EXAMINER BAREFORD, KATHERINE A ART UNIT PAPER NUMBER 1715 MAIL DATE DELIVERY MODE 10/29/2013 PAPER 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. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________ Ex parte DOUGLAS M. BERCZIK, DAVID A. LITTON, MELVIN FRELING, and KEVIN W. SCHLICHTING __________ Appeal 2012-006785 Application 12/751,091 Technology Center 1700 ____________ Before CHARLES F. WARREN, MICHAEL P. COLAIANNI, and DONNA M. PRAISS, Administrative Patent Judges. COLAIANNI, Administrative Patent Judge. DECISION ON APPEAL Appeal 2012-006785 Application 12/751,091 2 Appellants appeal under 35 U.S.C. § 134 the final rejection of claims 1-6 and 23-26. We have jurisdiction over the appeal pursuant to 35 U.S.C. § 6(b). We AFFIRM. Appellants’ invention is directed to a process for applying bond and thermal barrier coatings (Spec. para. [0002]). Claims 1, 23, 25, and 26 are illustrative: 1. A process for coating an article, comprising: applying upon at least one surface of a molybdenum based refractory metal alloy base or niobium based refractory metal alloy base substrate a bond coat layer consisting of from 60 to 90 percent by weight of a molybdenum disilicide base compound, from 10 to 40 percent by weight of silicon nitride, and optionally at least one of the following: silicon carbide and tantalum oxide; forming a functionally graded material layer comprising molybdenum disilicide, mullite and at least one of the following: silicon nitride, silicon carbide or tantalum oxide on said bond coat layer; and said functionally graded material layer forming step comprising forming said functionally graded material layer to increase in mullite composition from an interface with said bond coat layer to 100% by weight mullite at an interface with a subsequently applied thermal barrier coating layer. 23. The process of claim 1, wherein said functionally graded material layer forming step comprises forming said functionally graded material layer to have a coefficient of thermal expansion between about 3.0 x 10-6/°F and 4.5 x 10-6/0F. 25. The process of claim 1, wherein said subsequently formed thermal barrier coating comprises a material selected from the group consisting of mullite, zirconium silicate, yttrium silicate, yttrium disilicate, and magnesium aluminate spinel. 26. The process of claim 1, further comprising forming said substrate from a molybdenum base refractory metal alloy consisting of 91 weight percent to 98.5 weight percent molybdenum, Appeal 2012-006785 Application 12/751,091 3 1.5 weight percent to 4.5 weight percent silicon and 0.5 to 4.5 weight percent of boron based upon the weight of said alloy. Appellants appeal the following rejections1: 1. Claim 1, 2, 5, 6, and 23-25 are rejected under 35 U.S.C. § 103(a) as unpatentable over Lee (US 6,733,908 B1 issued May 11, 2004) in view of Chin (US 5,472,487 issued December 5, 1995). 2. Claim 26 is rejected under 35 U.S.C. § 103(a) as being unpatentable over Lee in view of Chin and Berczik (US 5,595,616 issued January 21, 1997). 3. Claims 1-6 and 23-25 are rejected under 35 U.S.C. § 103(a) as being unpatentable over Raybould (US 2005/0079343 A1 published April 14, 2005) in view of Lee, Scharman (US 5,320,909 issued June 14, 1994) and Payne (US 6,503,575 B1 issued January 7, 2003). 4. Claim 26 is rejected under 35 U.S.C. § 103(a) as being unpatentable over Raybould in view of Lee, Scharman, Payne, and Berczik. REJECTIONS (1) and (2) ISSUE Did the Examiner reversibly err in concluding that it would have been obvious to place a functionally graded material layer on the bond coat layer where the functionally graded material layer increases in mullite composition from an interface with the bond coat to 100% mullite at an interface with a subsequently applied thermal barrier coating layer as required in claim 1? We decide this issue in the affirmative. 1 The 35 U.S.C. § 112, second paragraph, rejection of claims 3 and 4 has been withdrawn by the Examiner (Ans. 4). Appeal 2012-006785 Application 12/751,091 4 FINDINGS OF FACT & ANALYSIS Appellants argue that neither Lee nor Chin teach or suggest forming a functionally graded layer between the bond coat and the thermal barrier coating (Reply Br. 4; App. Br. 11). Appellants contend that the Examiner’s explanation based upon addressing mismatch between the thermal expansion coefficients of the materials is based on hindsight (Reply Br. 4; App. Br. 11). While the Examiner finds that Lee teaches the concept of using a compositionally graded layer to control thermal expansion coefficient between layers (Ans. 19-20), Lee actually teaches forming a compositionally graded chemical barrier layer 22 between the outer layer 14 and the mullite- containing layer 20 (Lee, col. 7, ll. 47-67). The Examiner determines that one of ordinary skill in the art would have seen the benefits of providing such grading between other layers of Lee, such as between bond coat layers 20 and 24, to prevent cracking (Ans. 19). However, Lee does not indicate that there is any problem with thermal expansion coefficient mismatch between a bond coat and the thermal barrier coating. Indeed, as argued by Appellants, the only teaching to position a functionally graded material layer at the interface between the bond coat and a thermal barrier coating layer comes from Appellants’ disclosure. Accordingly, we determine that the Examiner has engaged in impermissible hindsight and reverse the Examiner’s § 103 rejections over Lee in view of Chin. Appeal 2012-006785 Application 12/751,091 5 REJECTIONS (3) and (4) ISSUES 1. Did the Examiner reversibly err in concluding that the combined teachings of Raybould, Lee, Scharman, and Payne would have rendered obvious the subject matter of claim 1? We decide this issue in the negative. 2. Did the Examiner reversibly err in concluding that the combined teachings of Raybould, Lee, Scharman, and Payne would have rendered obvious a functionally graded layer with a coefficient of thermal expansion within the range of about 3.0 x 10-6/°F to about 4.5 x 10-6/°F (claim 23) or using mullite as the thermal barrier coating (claim 25)? We decide this issue in the negative. 3. Did the Examiner reversibly err in concluding that it would have been obvious to use Berczik’s molybdenum-silicon-boron alloy as the molybdenum-silicon alloy in the process suggested by Raybould, Lee, Scharman, and Payne as recited in claim 26? We decide this issue in the negative. FINDINGS OF FACT AND ANALYSIS Issue (1): Claim 1 The Examiner’s findings and conclusions regarding Raybould, Lee, Scharman, and Payne are located on pages 11-14 of the Answer. Appellants argue that there is no reason, absent hindsight, why one of ordinary skill in the art would have replaced the silicon-based substrate of Raybould with a substrate formed from a molybdenum based refractory metal alloy or a niobium based refractory metal alloy (App. Br. 16). Appeal 2012-006785 Application 12/751,091 6 The Examiner finds that Raybould discloses using a silicon-based substrate for use in gas turbine components (Ans. 30), but does not explicitly state what materials are encompassed by the term “silicon-based” other than the exemplary citation to silicon nitride or silicon carbide (Ans. 30). The Examiner finds that Lee discloses that known silicon containing type materials for substrates in gas turbine engine components include not only silicon nitride or silicon carbide, but also silicon containing metal alloys, such as molybdenum-silicon (Ans. 30). The Examiner finds that there is no limit on what is considered “molybdenum based” or “niobium based” such that alloys with a presence of molybdenum or niobium and silicon can be considered based on either molybdenum or niobium and silicon (Ans. 31). The Examiner finds that the same issues regarding silicon oxidation that Raybould describes at paragraph 2 and solves would have been expected to be present in the specific molybdenum-silicon and niobium-silicon alloys described by Lee (Ans. 31). The Examiner determines that based on Lee’s and Raybould’s disclosures, Lee’s molybdenum-silicon alloy or niobium- silicon alloy would have been a suggested substrate for protection with Raybould’s method (Ans. 31). Appellants do not respond to these specific findings of the Examiner (Reply Br. 7-9). Appellants contend that the Examiner engaged in hindsight and that there is no reason to reconstruct Raybould in the manner that the Examiner suggests (Reply Br. 7). However, Raybould discloses that the silicon nitride and silicon carbide are merely exemplary types of silicon- based materials (paras. [0002], [0023], [0025]). Lee discloses that silicon nitride or carbide and molybdenum-silicon alloys or niobium-silicon alloys are known substrates for forming gas turbine components. Appellants’ Appeal 2012-006785 Application 12/751,091 7 argument that if molybdenum disilicide is used as the substrate then upon oxidizing the brazing composition the substrate would undesirably oxidize too is not persuasive. As noted in Raybould’s paragraph 0058, the brazing composition may contain silicon nitride, which is the same material that may comprise Raybould’s substrate. Raybould discloses that the silicon nitride in the coating is oxidized to form Si2ON2. Accordingly, using Raybould’s substrate material and brazing material oxidize does not appear to be necessarily undesirable. Or at least one of ordinary skill in the art would have known how to selectively oxidize the silicon nitride in the braze coating only. The preponderance of the evidence favors the Examiner’s determination that it would have been obvious to use Lee’s molybdenum- silicon alloy as the silicon-based substrate in Raybould’s process. Appellants argue that Raybould does not teach or suggest forming a mullite, molybdenum disilicide, and at least silicon nitride, silicon carbide, or tantalum oxide on the bond coat (App. Br. 16-17). Appellants argue that Lee’s compositionally graded layer decreases in mullite from the bond layer to the thermal barrier coating (App. Br. 17). Appellants contend that Payne fails to teach forming a functionally graded coating on a bond coat (App. Br. 17-18). Appellants’ arguments attack the disclosures of the references individually instead of addressing what the teachings of the references as a whole would have suggested to one of ordinary skill in the art. In re Keller, 642 F.2d 413, 425 (CCPA 1981). In the present case, Raybould discloses forming a thermal barrier coating 214 and that the environmental barrier coating 208 may be graded (Raybould para. [0034]). Raybould further discloses that thermal barrier coating 214 may be formed on a braze layer Appeal 2012-006785 Application 12/751,091 8 204 formed on a substrate (Raybould para. [0074]). The braze layer 204 may be formed from molybdenum disilicide and silicon nitride particles (paras. [0026] to [0027]). Payne discloses that it is desirable to provide a graded layer where a thermal oxide outer layer is attached to a metallic layer adjacent to the substrate in order to enhance the coating’s mechanical, thermal, and electrical properties (col. 4, ll. 34-50). Payne discloses that the graded layer may be either continuously graded in composition and properties or one or more layers of the coating may be maintained constant for a given thickness (col. 5, ll. 43-48). Payne discloses that the coating may be graded from a metal layer adjacent to the substrate to an oxide layer on the external surface of the coating (col. 6, ll. 10-14). Scharman teaches that it is known to use mullite as a thermal barrier coating to protecting metallic substrates in high temperature environments (col. 2, ll. 9-21). Lee, as noted supra, teaches that silicon containing materials in gas turbines includes molybdenum-silicon and niobium-silicon alloys (col. 8, ll. 18-37). The teachings of the references as a whole would have suggested forming a functionally graded layer of molybdenum disilicide, silicon nitride and mullite between a metallic layer of molybdenum disilicide and silicon nitride adjacent to a molybdenum-silicon alloy substrate and a thermal oxide outer layer of mullite. Contrary to Appellants’ argument that there would have been no reason to substitute Sharman’s mullite for Raybould’s columnar layer (Reply Br. 8), the substitution of Scharman’s mullite for Raybould’s yttria-stablizied-zirconia thermal oxide barrier material appears to be nothing more than a predictable use of a prior art element according to Appeal 2012-006785 Application 12/751,091 9 its established function (i.e., serving as a thermal barrier). KSR Int’l Co. v. Teleflex, Inc., 550 US 398, 417 (2007). We note that Raybould discloses that the thermal barrier coating 214 “may” include at least one segmented columnar ceramic layer which “may” comprise a stabilized zirconia or a stabilized hafnia (para. [0034]). Accordingly, Raybould’s thermal barrier material is not limited solely to the columnar material. While Appellants argue that there is no reason to construct Raybould’s coating with a functionally graded layer between the braze coat and the thermal barrier coating layer (App. Br. 18, Reply Br. 7), Payne, as found by the Examiner, provides that such a coating between a metallic layer adjacent a substrate and a thermal oxide barrier layer enhances the thermal, mechanical and electrical properties of the coating. The teachings of the references as a whole provide the motivation for making the combination. With respect to Appellants’ argument that Lee teaches away from having a functionally graded layer that increases in mullite content in a direction away from the substrate, the Examiner properly finds that Lee teaches the concept of providing a functionally graded chemical barrier layer 22 between two layers by increasing the amount of one component at the expense of another component so as to match the thermal expansion coefficients of the two layers being contacted by the graded layer 22 (Ans. 20). Payne reinforces the concept of applying this grading between a bond coat and thermal barrier coating. Accordingly, one of ordinary skill in the art would have understood from these teachings that the material of the functionally graded layer is varied from one concentration of a first coating material to a second concentration of a second material to control the Appeal 2012-006785 Application 12/751,091 10 thermal expansion coefficient of the graded layer and prevent cracking of the layer. We find that Lee’s teaching regarding the concentrations of the components is specifically tied to the structure of the layers being contacted by the functionally graded layer. Lee does not teach away from the claimed functionally graded layer increasing in mullite concentration. For the above, reasons we affirm the Examiner’s § 103 rejection of claims 1-6 and 24 over Raybould, Lee, Scharman, and Payne. Issue (2): Claims 23 and 25 Regarding claim 23, Appellants argue that there is no reason to optimize the thermal expansion coefficient of the graded layer because there is nothing in any of the references that requires the graded layer to have a thermal expansion coefficient within the range recited in claim 23 (App. Br. 19). However, Appellants’ arguments fail to address specifically the Examiner’s finding that the combined teachings of Raybould, Lee, Scharman, and Payne would have suggested using the same materials, in the same amounts for the graded layers such that the resulting thermal expansion coefficient would have been the same (Ans. 14). For the reasons noted supra, the preponderance of the evidence favors the Examiner’s conclusion that the teachings of Raybould, Lee, Scharman, and Payne would have been combined to arrive at the claimed process in order to control the matching of the thermal expansion coefficient between the coating layers. Based on the disclosures of the prior art, the functionally graded layer would have had a concentration that would have continuously varied throughout its thickness from a molybdenum disilicide and silicon Appeal 2012-006785 Application 12/751,091 11 nitride composition to a pure mullite composition. In so doing, one of ordinary skill in the art would have controlled and optimized the thermal expansion coefficient of the graded layer to enhance the mechanical properties of the coating as taught by Payne. In so doing, a thermal expansion coefficient within the claimed range would have been achieved as it is uncontested that the same materials and same amounts of the materials would have been used as taught by the combined teachings of the applied prior art. Regarding claim 25, Appellants argue that Raybould’s thermal barrier layer is formed from AlTaO4, an oxide of an element selected from Ta, Al, Hf, Ti, Zr, Mo, Nb, Ni, Sr, Sc, Y, Mg, Si, and the rare earth elements and there is no reason why one of ordinary skill would have substituted mullite for Raybould’s thermal barrier material (App. Br. 19). However, the Examiner’s basis for substituting Scharman’s mullite for Raybould’s thermal barrier material is based upon the predictable use of a known prior art element (i.e., mullite) according to its established function (i.e., a thermal barrier layer). KSR, 550 US at 417. (Ans. 39). Appellants do not respond or specifically challenge this position of the Examiner. Moreover, we note that Raybould discloses that the thermal barrier coating 214 “may” include at least one segmented columnar ceramic layer which “may” comprise a stabilized zirconia or a stabilized hafnia (para. [0034]). Raybould discloses that the environmental barrier coating 208 “may” be composed of AlTaO4, and oxide of an element selected from Ta, Al, Hf, Ti, Zr, Mo, Nb, Ni, Sr, Sc, Y, Mg, Si, and the rare earth elements (para. [0033]). Accordingly, Raybould’s thermal barrier material or environmental barrier coating is not limited solely to the columnar material. Appeal 2012-006785 Application 12/751,091 12 On this record, we affirm the Examiner’s § 103 rejection of claims 23 and 25 over Raybould, Lee, Scharman, and Payne. Issue (3): Claim 26 In light of the Examiner’s proposition to use Lee’s molybdenum- silicon alloy substrate in Raybould’s process, Appellants argue that the Examiner has not explained why one would then substitute Berczik’s molybdenum-silicon-boron alloy for Lee’s molybdenum-silicon alloy (App. Br. 20). Contrary to Appellants’ argument, the Examiner explains that Lee shows that it is known to use molybdenum-silicon alloys for making turbine components and that Berczik further teaches that using molybdenum-silicon- boron alloys are acceptable molybdenum-silicon alloys for use in turbines (Ans. 40). In other words, Berczik informs the teachings of Lee regarding acceptable molybdenum-silicon alloys for use in gas turbines. We do not find the Examiner engaged in impermissible hindsight in concluding that it would have been obvious to use Berczik’s molybdenum-silicon-boron alloy as the alloy for making gas turbines according to Lee and Raybould. Appellants’ argument that Raybould’s “silicon based” material excludes molybdenum-silicon alloys is not persuasive for reasons discussed supra regarding claim 1. On this record, we affirm the Examiner’s rejection of claim 26 over Raybould, Lee, Scharman, Payne, and Berczik. DECISION The Examiner’s decision is affirmed. Appeal 2012-006785 Application 12/751,091 13 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). ORDER AFFIRMED sld Copy with citationCopy as parenthetical citation