UNITED TECHNOLOGIES CORPORATIONDownload PDFPatent Trials and Appeals BoardMay 21, 202014912317 - (D) (P.T.A.B. May. 21, 2020) Copy Citation UNITED STATES PATENT AND TRADEMARK OFFICE 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. 14/912,317 02/16/2016 Michael G. ABBOTT 72389US02-U173-012237 9592 12208 7590 05/21/2020 Kinney & Lange, P.A. 312 South Third Street Minneapolis, MN 55415 EXAMINER PETERS, BRIAN O ART UNIT PAPER NUMBER 3745 NOTIFICATION DATE DELIVERY MODE 05/21/2020 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): USPatDocket@kinney.com amkoenck@kinney.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ____________________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________________ Ex parte MICHAEL G. ABBOTT, MICHAEL G. McCAFFREY, and GRANT O. COOK III __________________ Appeal 2019-006353 Application 14/912,317 Technology Center 3700 ____________________ Before JAMES P. CALVE, ANNETTE R. REIMERS, and GEORGE R. HOSKINS, Administrative Patent Judges. CALVE, Administrative Patent Judge. DECISION ON APPEAL STATEMENT OF THE CASE Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the decision of the Examiner to reject claims 1–4, 6, 7, 9–16, and 18–25, which are all the pending claims. Appeal Br. 2 (stating claims 5, 8, and 17 are cancelled). We have jurisdiction under 35 U.S.C. § 6(b). We REVERSE. 1 “Appellant” refers to “applicant” as defined in 37 C.F.R. § 1.42. Appellant identifies United Technologies Corporation as the real party in interest. Appeal Br. 2. Appeal 2019-006353 Application 14/912,317 2 CLAIMED SUBJECT MATTER Claims 1 and 14 are independent. Claim 1 is reproduced below. 1. An airfoil comprising: a ceramic core having a first surface; a skin having a second surface disposed over at least a portion of the first surface of the core, the skin comprising at least one ceramic matrix composite (CMC) material; and a plurality of bonds selected from one or both of a transient liquid phase (TLP) bond and a partial transient liquid phase (PTLP) bond disposed between the first surface and the second surface, the plurality of bonds joining the skin to the ceramic core; wherein the skin is spaced from the ceramic core by the plurality of bonds, defining a thermal protection space between the skin and the ceramic core. Appeal Br. 2 (Claims App.).2 REJECTION3 Claims 1–4, 6, 7, 9–16, and 18–25 are rejected under 35 U.S.C. § 103 as unpatentable over Jackson (US 5,626,462, iss. May 6, 1997), Merrill (US 8,137,611 B2, iss. Mar. 20, 2012), and Grant O. Cook III et al., Overview of Transient Liquid Phase and Partial Transient Liquid Phase Bonding, 46 J. Mater. Sci., 5305–5323 (2011) (hereinafter “Cook”). 2 Refers to the Appeal Brief that was filed December 22, 2017 in response to a Notice of Non-Compliant Appeal Brief, mailed December 15, 2017. All other references to the Appeal Brief are to the Appeal Brief that was filed October 2, 2017. 3 The Examiner withdrew a rejection of claims 6 and 7 under 35 U.S.C. § 112(b) for indefiniteness. See Adv. Act., mailed June 29, 2017. Appeal 2019-006353 Application 14/912,317 3 ANALYSIS Examiner’s Findings and Determinations Regarding independent claims 1 and 14, the Examiner cites Jackson for its teaching of an airfoil and method of making an airfoil including a core (airfoil support wall 40) with a first surface (outer surface 48), a skin (airfoil skin 42) with a second surface (adjacent to outer surface 48) disposed over at least a portion of the core’s first surface 48 with a plurality of bonds formed between the first and second surfaces to space core 40 from skin 42 to define a thermal protection space (internal channel 52) as illustrated in Figure 1A, but the Examiner finds that Jackson lacks a ceramic core and ceramic matrix composite (CMC) as claimed. Final Act. 3, 7. The Examiner finds that Merrill teaches a similar airfoil that bonds a ceramic core 14 to a CMC skin (shell 12) with a bond layer 18 that joins the first surface of the core 14 and second surface of the skin 12 as claimed. Id. at 3, 7; Ans. 3. The Examiner finds that the airfoil operates at temperatures higher than metal alloy materials due to the ceramic materials. Final Act. 3 (citing Merrill, 1:37–43), 7 (citing the same). The Examiner determines that it would have been obvious to modify the materials in Jackson’s airfoil to use a ceramic core and CMC skin, as taught by Merrill, “to have an airfoil that operates at higher operating temperatures than an airfoil made with metal alloy materials” due to the ceramic properties. Id. at 3–4, 7–8; Ans. 3. The Examiner finds that Cook uses transient liquid phase (TLP) and partial transient liquid phase (PTLP) bonding to bond two ceramic materials and determines that it would have been obvious to substitute Merrill’s bond with the PTLP bond of Cook to achieve a predictable result of creating a bond between two ceramic components. Final Act. 4, 8; Ans. 3. Appeal 2019-006353 Application 14/912,317 4 Appellant’s Contentions Appellant argues that Merrill’s co-processing method uses skin 12 as a mold for core 14 with monolithic bond layer 18 completely encompassing the adjacent surfaces of core 14 and skin 16 to reduce internal strain damage and delamination compared to structures using secondarily bonded elements and thus cannot be modified to produce a plurality of spaced apart bonds that form a thermal protection space as claimed in Jackson. Appeal Br. 8–9, 11– 12. Appellant argues that Merrill teaches away from a secondary bonding such as Cook’s TLP or PTLP bonding that forms a skin and core separately and then bonds the elements together by secondary bonds that reduce the bond strength and/or cause glassy phases in the bond as compared to co- processing the skin and core to form a bond layer as in Merrill. Id. at 13. Principles of Law A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. 35 U.S.C. § 103. Obviousness is a question of law based on underlying findings of fact. . . . The underlying factual findings include (1) “the scope and content of the prior art,” (2) “differences between the prior art and the claims at issue,” (3) “the level of ordinary skill in the pertinent art,” and (4) the presence of secondary considerations of nonobviousness. In re Warsaw Orthopedic, Inc., 832 F.3d 1327, 1329–30 (Fed. Cir. 2016) (citations omitted). Appeal 2019-006353 Application 14/912,317 5 Obviousness Analysis The Examiner is correct that Jackson teaches an airfoil with metallic skin 42 metallurgically bonded to an inner core (support wall 40) at multiple points to define thermal protection spaces (internal channels 52). Final Act. 3, 7; Ans. 2. The Examiner is correct that Merrill teaches a two-component airfoil comprising CMC outer skin 12 and ceramic core 14 bonded together at bond layer 18. Final Act. 3, 7; Ans. 3. However, because Merrill bonds CMC shell 12 to ceramic core 14 by co-processing, we are not persuaded that Merrill “lack[s] [a] teaching [of] a particular type of bond between the ceramic core and ceramic skin,” such that a skilled artisan would consider Cook’s teachings to bond an outer CMC shell to an inner ceramic core and define a thermal protection space therebetween. Ans. 3; see Final Act. 3–4. Merrill’s airfoil 10 comprises continuous CMC shell 12 that encases solid ceramic core 14. Merrill, 6:13–17. Merrill’s airfoil is formed by “co- processing” in which CMC shell 12 is used as a mold into which a solid core ceramic is cast. Then, shell 12 and core 14 are fired to form a sintered bond between the two materials and create a CMC/solid core airfoil that deforms better in response to internal strain and can handle differential dimensional changes resulting from sintering, drying shrinkage, densification shrinkage, and thermal expansion mismatches of materials to resist delamination during use better than prior art articles. Id. at 2:1–4:48. Merrill also forms a split line in the solid core to reduce internal strain in one dimension, to accelerate the drying process on the pressure side and suction side of the article so that sinterable species migrate to the bond line, and to relax stress at intermediate temperatures to increase the life of the article/airfoil. Id. at 4:49–5:41. We reproduce Figure 1 of Merrill with Figure 1A of Jackson below. Appeal 2019-006353 Application 14/912,317 6 Figure 1 of Merrill illustrates airfoil 10 comprising CMC shell 12 and solid core 14 with split line 16 and bond layer 18 between shell 12 and core 14. Id. at 6:13–21. Figure 1A of Jackson illustrates an airfoil comprising partially-hollow airfoil support wall 40 with an airfoil-shaped outer surface 48 to which airfoil skin 42 is metallurgically bonded to form double-walled structure 50. Jackson, 4:7–20. Appeal 2019-006353 Application 14/912,317 7 The Examiner is correct that Merrill teaches the benefits of ceramic airfoils (CMC shell and solid ceramic core) to operate at higher temperatures than metal alloys. Merrill, 1:25–40; Final Act. 3–4, 7. However, Merrill forms an airfoil of ceramic components using a co-processing method that forms a continuous sintered bond between the inner surface of outer CMC shell 12 and the outer surface of inner core 14 to manage internal strain and prevent delamination. Merrill, 2:35–5:10; Appeal Br. 9–12. If a bonding layer 18 is used, it is applied to the interior surface of CMC shell 12 to form a continuous bond between CMC shell 12 and the outer surface of inner core 14 as depicted in Figure 1 of Merrill above. Merrill, 3:9–18, 6:20–21. Merrill teaches that secondary bonding processes may be used to form a ceramic airfoil such as laying up a CMC shell on a prefired refractory core, but the bond layer strength may be less than a refractory bond formed by the co-processing method. Id. at 5:11–20. Merrill thus recognizes that an airfoil can be formed by bonding an outer CMC shell to an inner core, but teaches that co-processing provides a stronger bond. Id. Even if a skilled artisan would choose Cook’s TLP and PTLP bonds as an engineering trade off of some sort, neither Cook nor Merrill teaches to form a plurality of separated bonds between a CMC shell and ceramic core “defining a thermal protection space between the skin and the ceramic core” as claimed. We appreciate that the Examiner relies on Jackson to teach a plurality of separate metallurgical bonds that define thermal protection spaces 52 between skin 42 and core 40 as illustrated in Figure 1A above. Final Act. 3, 7. However, to make Jackson’s airfoil out of ceramic components, Merrill teaches to co-process the CMC shell and ceramic core to form a continuous, sintered bond, or, alternatively, a continuous bond layer 18, between them. Appeal 2019-006353 Application 14/912,317 8 None of the references forms an airfoil from a ceramic core that has a plurality of channels in its outer surface and a CMC shell bonded to the core by TLP/PTLP bonds. Merrill makes a ceramic airfoil by co-processing an outer CMC shell that serves as a form for a ceramic core so their adjoining surfaces are sintered together to form a continuous bond to reduce internal strain and delamination. See Appeal Br. 9–11; Merrill, 2:1–5:28. If Merrill uses a split line 16 or air channel in core 14, Merrill forms those elements inside core 14 rather than by forming spaced bonds or thermal protection spaces between shell 12 and core 14. Merrill, 1:30–33, 4:49–5:59, Fig. 1. Jackson forms channels 52 in an outer surface of inner support wall 40 to circulate a cooling gas. Jackson, 4:55–65. Merrill casts air channels inside the core to direct cooling air through the channels. Merrill, 1:25–33, Fig. 1. Forming air channels within the core allows the core to be cast inside the CMC shell with outer surface bonded to the inner surface of CMC shell as illustrated in Figure 1 of Merrill to improve strength and reduce internal strain and delamination. Merrill also forms split line 16 within solid core 14 to improve bonding and the qualities of the finished article so it deforms in response to internal strain rather than delaminates. Id. at 4:49–5:59. Merrill thus uses a particular configuration and process to make a dual-component ceramic airfoil. Even if Merrill’s CMC shell 12 is bonded to inner core 14 by TLP/PTLP bonds, as the Examiner proposes (see Final Act. 4), there is no teaching to form the TLP/PTLP bonds with spaces or channels between them as Jackson bonds support wall 40 to outer skin 42. Merrill forms a core and shell with a continuous sintered bonded surface, or if bond layer 18 is used, it forms a continuous layer along adjacent, continuous surfaces of CMC shell 12 and inner ceramic core 14. Merrill 3:9–18, 6:13–21, Fig. 1. Appeal 2019-006353 Application 14/912,317 9 The Examiner’s finding that Jackson forms plural bonds between a metal core 40 and outer skin 42 to define a thermal protection space does not explain why a skilled artisan would maintain this configuration when the shell and core are ceramic materials, and Merrill teaches to co-process and sinter them together along their entire adjoining surfaces. See Final Act. 3– 4; see also Merrill 1:64–2:13, 2:44–5:10, Figs. 1–3. If a secondary bonding process is used to join a CMC shell and ceramic core, Merrill uses a single bond layer applied to the inner surface of a CMC shell as a slurry with high sintering activity, a glass frit, or a glass-ceramic type bond layer rather than as a plurality of separate bonds that define thermal protection spaces as claimed. Merrill 3:9–18, 5:11–20, 6:13–21. Merrill teaches that secondary bond layers have lower bond strength or glassy phases compared to a bond formed by co-processing. Merrill does not teach or suggest to bond CMC shell 12 to core 14 with plural bonds that form thermal spaces between the shell and core as claimed. Id. at 5:11–20. Nor does Cook teach or suggest to use a plurality of TLP or PTLP bonds defining thermal protection spaces between a ceramic shell and core as claimed. Accordingly, we do not sustain the rejection of claims 1 and 14 or their respective dependent claims 2–4, 6, 7, 9–13, 15, 16, and 18–25. CONCLUSION Claims Rejected 35 U.S.C. § Reference(s)/ Basis Affirmed Reversed 1–4, 6, 7, 9–16, 18–25 103 Jackson, Merrill, Cook 1–4, 6, 7, 9–16, 18–25 REVERSED Copy with citationCopy as parenthetical citation