Ex Parte Frost et al

Patent Trial and Appeal BoardAug 23, 2013

11366900 (P.T.A.B. Aug. 23, 2013)

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. 11/366,900 03/01/2006 Aaron T. Frost 085.11691-US (05-464) 4221 52237 7590 08/23/2013 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 08/23/2013 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 AARON T. FROST and JOSE QUINONES ____________ Appeal 2012-003728 Application 11/366,900 Technology Center 1700 ____________ Before ANDREW HAROLD METZ, CHUNG K. PAK, and LINDA M. GAUDETTE, Administrative Patent Judges. METZ, Administrative Patent Judge. DECISION ON APPEAL Appeal 2012-003728 Application 11/366,900 2 STATEMENT OF THE CASE Appellants appeal under 35 U.S.C. § 134 from the Examiner’s decision rejecting claims 1 through 6, 8 through 13 and 25, which are all the claims remaining in the application. We have jurisdiction under 35 U.S.C. § 6. We AFFIRM. THE INVENTION Appellants’ invention is directed to a process for preparing thermal barrier coatings (TBCs) useful for protective coatings to inhibit the flow of heat into articles routinely cycled from ambient conditions up to extreme conditions such as parts used in a gas turbine. According to Appellants, air plasma sprayed TBCs are “well known” and have been used for several decades. Spec. [0002]. Appellants further represent that prior art TBCs are formed from powdered metal oxides such as yttria stabilized zirconia and are formed by heating a gas-propelled spray of the powdered metal oxide using a plasma spray torch. The spray of the molten metal oxide particles is directed onto a receiving metal surface or substrate of an article formed from, for example, high temperature Ti-based, Ni-based, or Co-based superalloy to form a layer of the TBC on the substrate. To obtain the necessary thickness the process may be repeated. Typical thickness of the final TBC is generally no greater than 0.1 inches. Id. at [0003]. Appellants disclose that a well-recognized problem with prior art TBCs is that exposure to intense heat and rapid temperature changes can cause their failure by spallation or spalling of the TBCs from the surface of Appeal 2012-003728 Application 11/366,900 3 the metal articles which the TBCs are designed to protect. Susceptibility to spallation is understood to be due primarily to the existence of horizontal cracking or in-plane (of the TBC) cracking. Horizontal cracks are known particularly to increase the susceptibility of TBCs to spallation because in- plane stresses created during the TBC deposition process or in service stresses can cause horizontal cracks to propagate and grow. Id. at [0004]. Notwithstanding the well-known problem with spallation, Appellants represent that it is also known that resistance to spallation can be improved by modifying characteristics of the coatings. For example, the performance in known stabilized zirconia TBCs is enhanced by developing a predominance of cracks normal to the TBC/article being coated interface and having a minimum of cracks parallel to said interface. Appellants cite to patents to Taylor (5,073,433) and Gray (5,830,586) as evidence of known prior art solutions to spalling of the TBC. Id. at [0005]. At page 3 of their Specification, Appellants allege to have discovered they can overcome the problems with prior art processes for applying TBCs to metal substrates by: (1) applying upon a bond coat layer a thermal barrier coat comprising particles having a particle size distribution of no less than 8 microns and no more than 88 microns; (2) heat treating said thermal barrier coating at a temperature of between about 1,800ºF to 2,200ºF for about 2 to 4 hours at a pressure of from 1x10-3 torr to 1x10-6 torr; and, (3) forming a thermal barrier coating layer having a cracking density of no more than about 20 cracks per linear inch of said coating layer. Id. at [0007]. See also Fig. 3 from Appellants’ Specification. Appeal 2012-003728 Application 11/366,900 4 Claim 1 is believed to be adequately representative of the appealed subject matter and is reproduced below for a more facile understanding of the claimed invention. 1. A process for coating an article, comprising: applying a bond coat layer onto at least one surface of an article; forming a thermal barrier coating layer having an average density value of at least 98%, a cracking density in the range of from 1 – 20 cracks per linear inch, and an average porosity of no more than 5% on said bond coat layer; said forming step comprising providing a powder having a particle size distribution in the range of from 8 to 88 microns, plasma spraying said powder upon said bond coat layer to form said thermal barrier coating layer, and heat treating said thermal barrier coating composition at a temperature of between about 1,800ºF to 2200ºF for about 2 hours to 4 hours at a pressure of about 1x10-3 torr to 1x10-6 torr. The references of record which are being relied on by the Examiner as evidence of obviousness are: Taylor et al. (Taylor) 5,520,516 May 28, 1996 Bernecki et al. (Bernecki) 5,744,777 Apr. 28, 1998 Vakil 5,902,638 May 11, 1999 Torigoe et al. (Torigoe) 6,548,161 B1 Apr. 15, 2003 THE REJECTIONS Claims 1 through 6, 12 and 13 stand rejected as being unpatentable under 35 U.S.C. § 103(a) as the subject matter claimed therein would have Appeal 2012-003728 Application 11/366,900 5 been obvious at the time Appellants made their invention from the disclosure of Taylor1 considered with Torigoe. Claims 8 through 11 stand rejected as being unpatentable under 35 U.S.C. § 103(a) as the subject matter claimed therein would have been obvious at the time Appellants made their invention from the disclosure of Taylor considered with Torigoe and Bernecki. Claim 25 stands rejected as being unpatentable under 35 U.S.C. § 103(a) as the subject matter claimed therein would have been obvious at the time Appellants made their invention from the disclosure of Taylor considered with Torigoe, and Vakil. OPINION Each of the prior art rejections before us is founded on the combination of Taylor with Torigoe. The rejection of claims 8 through 11 additionally relies on Bernecki. The rejection of claim 25 additionally relies on Vakil. Appellants rely on their arguments made with respect to the rejection of claims 1 through 6, 12 and 13 for why we should reverse the Examiner’s rejection as to claims 8 through 11 and 25. Accordingly, we shall limit our review to the rejections as they are founded on the combination of Taylor with Torigoe. The issue before us is a question of law, specifically, whether the subject matter claimed by Appellants would have been obvious in the sense of the statute to the hypothetical person of ordinary skill in the art at the time Appellants made their invention. The ultimate legal conclusion of 1 The Examiner and Appellants refer to Taylor in their Answer and Brief, respectively, as “Taylor ‘516” and “Taylor et al.” Appeal 2012-003728 Application 11/366,900 6 obviousness is based on the underlying facts in each specific case including the scope and content of the prior art, the differences between the claimed invention and the prior art and the level of ordinary skill in the relevant art. We have carefully considered the entire record before us, including Appellants’ Specification and claims, the prior art on which the Examiner has relied to reject Appellants’ claims, Appellants’ arguments in support of the patentability of their claims, the alleged errors in the Examiner’s stated rejections, the Examiner’s stated rejections and the rationale offered in support of her rejections and the Examiner’s responses to Appellants’ various arguments made in their Brief. Based on our review we conclude that the Examiner has made out a prima facie case of obviousness with respect to the claimed subject matter. Appellants urge that the Examiner erred in rejecting the claimed process because: (1) while Taylor does disclose preparing a thermal barrier coating having a density of at least 88% of the theoretical density, Taylor does not disclose an average density value of at least 98%; (2) nothing in Taylor teaches or suggests providing a powder having a particle size of from 8 to 88 microns; (3) while Taylor discloses heat treatment at a temperature in the range of from 1800ºF to 2200ºF for a period of from 2 to 4 hours, nothing in Taylor suggests the claimed pressure used in Appellants’ process. For reasons that follow we do not find Appellants’ arguments to be persuasive. Except for claims12, 13 and 25, Appellants’ process does not recite or require any particular material used to form the bond coat layer or thermal barrier coating layer in Appellants’ process. Rather, the claims recite a Appeal 2012-003728 Application 11/366,900 7 process requiring “applying a bond coat layer” and “forming a thermal barrier coating layer” wherein the “forming step” comprises providing a powder having particular physical properties, plasma spraying the powder on the bond coat layer and heat treating under reduced pressure the thermal barrier coating layer. The claims also recite that the thermal barrier coating layer as prepared by the claimed process steps has certain physical properties (“average density”, “cracking density” and “average porosity”). We find Taylor to be evidence that at the time Appellants made their invention it was known to prepare thermal barrier coating layers on metal alloys useful in gas turbines by first applying a bond coat layer on the metal alloy by conventional plasma spray techniques or other “conventional” techniques and subsequently forming a thermal barrier coating on the bond coat layer. Column 5, lines 28 through 39. See also Appellants’ discussion of the conventional techniques used in the prior art in paragraph [0017] of their Specification bridging pages 5 and 6 of the Specification. The thermal barrier layer comprises a zirconium-based oxide (column 2, lines 62-63) and the zirconium-based oxide may be stabilized with yttria, calcium oxide, cerium oxide or magnesium oxide (column 3, lines 25 through 35). The zirconium-based oxide is sized 120 Tyler mesh or finer (column 3, lines 14- 15). Taylor discloses that a heat treatment of the coating at 1800ºF to 2200ºF for a period of from 1 to 10 hours under a vacuum improves its erosion resistance (column 6, lines 23 through 46). We agree with the Examiner that the language “of at least 88% of the theoretical density” would have been understood to mean from 88% up to 100% of the theoretical density. We reject Appellants’ argument that the Appeal 2012-003728 Application 11/366,900 8 failure of Taylor to place an upper limit on the limitation “at least 88% of the theoretical density” renders Taylor “non-enabling” with respect to Appellants’ claimed average density value of “at least 98%.” In the first instance, the language “at least . . .” is well understood to mean the amount actually recited but not less than the amount recited, here 88%, or more than the recited amount. Indeed, Appellants recognize that “the phrase at least 88% only sets a lower limit.” Brief, page 8. Appellants’ average density “of at least 98%” is therefore included in Taylor’s disclosed range. In re Peterson, 315 F.3d 1325, 1329-30 (Fed. Cir. 2003)(“In cases involving overlapping ranges, we and our predecessor court have consistently held that even a slight overlap in range establishes a prima facie case of obviousness.”) Further, Appellants’ argument that Taylor is “non-enabling” with respect to the “claimed average density value” is not persuasive. Taylor’s disclosure is presumed to be enabling. In re Antor Media Corp., 689 F.3d 1282, 1288 (Fed. Cir. 2012); In re Sasse, 629 F.2d 675, 681(CCPA 1980); In re Spencer, 261 F.2d 244, 246 (CCPA 1958). Yet, on this record, Appellants have presented no persuasive argument and/or no evidence explaining why the skilled routineer would have been unable to increase the density of the coating to more than 88% of the theoretical density according to Taylor’s disclosure, without engaging in undue experimentation2. 3 2 Undue experimentation is determined based on both the nature of the invention and the state of the art. See Elan Pharm., Inc. v. Mayo Found. for Med. Educ. & Research, 346 F.3d 1051, 1055 (Fed. Cir. 2003) (quoting In re Wands, 858 F.2d 731, 737 (Fed. Cir. 1988). Appeal 2012-003728 Application 11/366,900 9 Appellants’ claims do not recite that a particle having a particle size in the range of from 8 to 88 microns is used to prepare the thermal barrier coating. Rather, the claims require a powder having a particle size distribution in the range of from 8 to 88 microns. Thus, Appellants’ claims utilize a powder comprising a mixture of particles whose particles have a range of sizes from 8 to 88 microns. Taylor’s disclosure of using a powder sized 120 Tyler mesh (around 100 microns) or less would have been understood to mean around 100 microns or less. Thus, using a powder sized finer than 120 Tyler mesh would have been understood to mean a powder sized less than 100 microns. Appellants’ claimed particle size distribution of from 8 to 88 microns is therefore included by Taylor’s disclosure of 120 Tyler mesh or finer. Peterson, 315 F.3d at1329-30. Similarly, Taylor discloses a heat treatment that, like Appellants, is performed at from 1800ºF to 2200ºF for from 1 to 10 hours under a vacuum. Taylor recognizes that the heat treatment improves the coating’s resistance to oxidation (column 6, lines 23 through 37). While Taylor does not specifically disclose the reduced pressure claimed the Examiner has relied on Torigoe as evidence that the reduced pressure described in Taylor would have been understood as including the claimed pressure range. Specifically, Torigoe describes a process as claimed wherein in order to enhance bonding strength and corrosion and erosion resistance of the coating a vacuum heat treatment of the coating is undertaken at 1000ºC (around 1800ºF) at 10-3 to 3 In any event, “a non-enabling reference may qualify as prior art for the purpose of determining obviousness under § 103.” See Symbol Techs. Inc. v. Opticon Inc., 935 F.2d 1569, 1578 (Fed. Cir. 1991) Appeal 2012-003728 Application 11/366,900 10 10-4 torr. We are satisfied that the person of ordinary skill in the art would have been motivated to use as the pressure in Taylor’s vacuum heat treating step the pressure disclosed in Torigoe’s process because both references disclose that vacuum heat treating improves the coating’s resistance to erosion and corrosion. The particular powders recited in claims 12, 13 and 25 include yttria- stabilized zirconia. Taylor’s preferred powder is a yttria-stabilized zirconia (column 5, lines 24 through 27). Thus, the prior art specifically teaches using one of Appellants’ claimed powders as the preferred powder in the prior art’s processes for forming thermal coating barriers. Appellants’ argument that there is no basis in the prior art for substituting yttria stabilized hafnia for the stabilized zirconate of Taylor in the process of claim 25 ignores the language of claim 25. Claim 25 does not require yttria- stabilized hafnia. Rather, yttria-stabilized hafnia is only one of several powders recited in claim 25, including “stabilized zirconate” and Taylor specifically describes yttria-stabilized zirconia as preferred in their process. We have carefully considered the disclosure in Appellants’ Specification in paragraphs [0026] through [0028] wherein Appellants compare a part “coated in accordance with the prior art processes” and a different part coated “utilizing a method and coating composition of the present invention.” According to Appellants, comparing the results shown in FIGS 4 and 5 shows the coatings applied by the claimed process exhibits overall improved properties compared to the prior art. We disagree. The heat treatment for the part prepared according to the process claimed by Appellants was conducted at 2,050ºF but was not heat treated at a pressure Appeal 2012-003728 Application 11/366,900 11 of from 1x10-3 torr to 1x10-6 torr. Rather, the yttria-stabilized zirconia was applied under a vacuum, a step neither recited nor required by Appellants’ claims. Moreover, the density for the two parts prepared is stated to be the “aggregate density”, “aggregate cracking density” and “aggregate porosity.” The claims recite an “average density”, “aggregate cracking density” and “aggregate porosity.” Thus, we have no way of knowing what is being compared. In presenting evidence argued to represent “unexpected” or improved results, Appellants bore the burden of demonstrating that what was being compared was truly comparable and representative of the prior art and that actual differences in properties exist between what is claimed and the prior art and that the differences are meaningful and truly “unexpected.” See In re Geisler, 116 F.3d 1465, 1470 (Fed. Cir. 1997); In re Baxter Travenol Labs., 952 F.2d 388, 392 (Fed. Cir. 1991); In re Freeman, 474 F.2d 1318, 1324 (CCPA 1973); In re Dunn, 349 F.2d 433,439 (CCPA 1965). This Appellants proffered comparison from the Specification fails to do. While all Appellants’ claims are directed to a process, all Appellants’ claims recite various physical properties (“average density”, “cracking density” and “average porosity”) for the product obtained by the claimed process. To that extent, we are satisfied that because Appellants’ coating is obtained by a process we have found to be obvious, application of the law for product-by-process claims persuades us that because Appellants’ claimed coating and the prior art coatings are prepared by substantially the same steps (“applying a bond coat”, “forming a thermal barrier coating”, “providing a powder having a particle size distribution in the range of from 8 to 88 microns”, “plasma spraying said powder upon said bond coat layer” Appeal 2012-003728 Application 11/366,900 12 and “heat treating said thermal barrier coating composition”) it would have been expected by the hypothetical person of ordinary skill in the art at the time Appellants made their invention that the products produced by the two methods would have at least been substantially the same and, therefore, prima facie obvious. We also find unpersuasive Appellants’ argument that the Examiner has provided no rationale for her argument that it would have been obvious to optimize the various parameters disclosed in the prior art to obtain coatings having the claimed physical properties. When the prior art discloses process variables described by a range of values that process would have been expected to be useful over the entire disclosed range. Moreover, presuming the hypothetical person in the relevant art is skilled not unskilled, we agree with the Examiner’s conclusion that experimenting with the disclosed prior art processes over the entire range of variables disclosed would have been well within routine experimentation by the skilled routineer. The decision of the Examiner is affirmed. 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)(iv). AFFIRMED bar