IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`
`
`In re U.S. Patent No. 7,060,360
`
`Filed:
`
`May 22, 2003
`
`Issued:
`
`June 13, 2006
`
`Inventors: Harry E. Eaton, Ellen Y. Sun, Stephen Chin
`
`Assignee: United Technologies Corporation
`
`Title:
`
`
`Bond Coat for Silicon Based Substrates
`
`
`DECLARATION OF ANDREAS M. GLAESER, PH.D.
`
`I, Andreas M. Glaeser, make this declaration in connection with the petition
`
`
`
`for inter partes review submitted by Petitioner for U.S. Patent No. 7,060,360 (“the
`
`360 Patent”). All statements made herein of my own knowledge are true, and all
`
`statements made herein based on information and belief are believed to be true.
`
`Although I am being compensated for my time in preparing this declaration, the
`
`opinions articulated herein are my own, and I have no stake in the outcome of this
`
`proceeding or any related litigation or administrative proceedings.
`
`I.
`
`INTRODUCTION
`
`1.
`
`I am making this declaration at the request of the General Electric
`
`Company in the matter of the Inter Partes Review of U.S. Patent No. 7,060,360
`
`GE-1003.001
`
`

`
`(“the 360 Patent”) to Eaton et al.
`
`2. In the preparation of this declaration, I have reviewed the relevant
`
`portions of the following documents:
`
`GE-1001
`
`U.S. Patent No. 7,060,360 to Eaton et al.
`
`GE-1002
`
`Prosecution File History of U.S. Patent No. 7,060,360
`
`GE-1005
`
`U.S. Patent No. 5,677,060 to Terentieva et al (“Terentieva”).
`
`GE-1006
`
`U.S. Patent No. 6,387,456 to Eaton et al (“Eaton 456”).
`
`GE-1007
`
`GE-1008
`
`GE-1009
`
`GE-1010
`
`GE-1011
`
`GE-1012
`
`GE-1013
`
`GE-1014
`
`GE-1015
`
`A.K. Vasudévan & J.J. Petrovic, A Comparative Overview of
`Molybdenum Disilicide Composites, Materials Science and
`Engineering, vol. A155, Nos. 1-2 (Jun. 1992), pp. 1-17.
`European Patent App. No. 1142850 A1 to Wang et al.
`(“Wang”).
`U.S. Patent No. 6,517,341 to Brun et al. (“Brun”).
`
`D.R. Clarke & C.G. Levi, Materials Design for the Next
`Generation Thermal Barrier Coatings, 33 Annu. Rev. Mater.
`Res., Apr. 18, 2003, pp. 383-417.
`K.N. Lee, Current Status of Environmental Barrier Coatings for
`Si-Based Ceramics, Surface and Coatings Technology, vols.
`133-134 (Nov. 200), pp. 1-7.
`N. Bornstein, Oxidation of Advanced Intermetallic Compounds,
`Journal de Physique IV, vol. 3, No. C9, (Dec. 1993), pp. C9-
`367-73.
`U.S. Patent No. 5,985,470 to Spitsberg et al. (“Spitsberg”).
`
`K.N. Lee et al., Environmental Barrier Coatings for Silicon-
`Based Ceramics, High Temperature Ceramic Matrix
`Composites, 4th Int’l Conf. on High Temp. Ceramic Matrix
`Composites (HT-CMC4), Oct. 1-3, 2001.
`R. Gibala et al., Mechanical behavior and interface design of
`MoSi2-based Alloys and Composites, Mater. Sci. Eng., vol.
`A155, No. 1-2 (Jun. 1992), pp. 147-158.
`
`
`
`2
`
`GE-1003.002
`
`

`
`GE-1016
`
`GE-1017
`
`GE-1018
`
`GE-1019
`
`GE-1020
`
`GE-1021
`
`GE-1022
`
`GE-1023
`
`GE-1024
`
`GE-1025
`
`GE-1026
`
`Dilip M. Shah, MoSi2 and Other Silicides as High Temperature
`Structural Materials, Superalloys, (1992), pp. 409-422.
`J.-C. Zhao & J. H. Westbrook, Ultrahigh-Temperature
`Materials for Jet Engines, MRS Bulletin, vol. 28, No. 9, (Sep.
`2003), pp. 622-26.
`M. Tsirlin et al., Experimental Investigation of Multifunctional
`Interphase Coatings on SiC Fibers for Non-Oxide High
`Temperature Resistant CMCs, High Temperature Ceramic
`Matrix Composites, 4th Int’l Conf. on High Temp. Ceramic
`Matrix Composites (HT-CMC4), Oct. 1-3, 2001.
`Nathan S. Jacobson, Corrosion of Silicon-Based Ceramics in
`Combustion Environments, J. Am. Ceram. Soc., vol. 76, No. 1,
`(Jan. 1993), pp. 3-28.
`Paul J. Jorgensen et al., Effects of Water Vapor on Oxidation of
`Silicon Carbide, J. Am. Ceram. Soc., vol. 44, No. 6 (Jun. 1961),
`pp. 258-61.
`Yongdong Xu et al., Oxidation Behavior and Mechanical
`Properties of C/SiC Composites with Si-MoSi2 Oxidation
`Protection Coating, J. Mater. Sci., vol. 34, No. 24, pp. 6009-14
`(Dec. 1999).
`S. Kamakshi Sundaram et al., Molten Glass Corrosion
`Resistance of Immersed Combustion-Heating Tube Materials in
`E-Glass, J. Am. Ceram. Soc., vol. 78, No. 7 (Jul. 1995), pp.
`1940-46.
`Y. L. Jeng, E. J. Lavernia, Review Processing of Molybdenum
`Disilicide, J. Mater. Sci., vol. 29, No. 10, pp. 2557-71 (Jan.
`1994).
`Yoshikazu Suzuki et al., Improvement in Mechanical Properties
`of Powder-Processed MoSi2 by the Addition of Sc2O3 and Y2O3,
`J. Am. Ceram. Soc., vol. 81, No. 12 (Dec. 1998), pp. 3141-49.
`J. D. Webster et al., Oxidation Protection Coatings for C/SiC
`Based on Yttrium Silicate, J. Eur. Cer. Soc., vol. 18, No. 16
`(Dec. 1998), pp. 2345-50.
`J.J. Petrovic et al., Molybdenum Disilicide Materials for Glass
`Melting Sensor Sheaths, 25th Annual Conf. on Composites,
`Advanced Ceramics, Materials, and Structures: A, Ceramic
`Engineering and Science Proceedings, vol. 22, No. 3 (Jan.
`2001), pp. 59-64.
`
`
`
`3
`
`GE-1003.003
`
`

`
`GE-1027
`
`GE-1028
`
`GE-1029
`
`H. Kahn et al., Fracture toughness of polysilicon MEMS
`devices, Sensors and Actuators, vol. 82, No. 1-3 (May 2000), pp.
`274-80.
`C.L. Muhlstein et al., A reaction-layer mechanism for the
`delayed failure of micron-scale polycrystalline silicon structural
`films subjected to high-cycle fatigue loading, Acta Materialia,
`vol. 50, No. 14 (Aug. 2002), pp. 3579-95.
`S. Kamakshi Sundaram et al., Molten Glass Corrosion
`Resistance of Immersed Combustion-Heating Tube Materials in
`Soda-Lime-Silicate Glass, J. Am. Ceram. Soc., vol. 77, No. 6
`(Jun. 1994), pp. 1613-23.
`
`
`In forming my opinions expressed below, I have considered the
`
`3.
`
`documents listed above, and my knowledge and experience based upon my work in
`
`this area as described below.
`
`4.
`
`The application that led to the issuance of the 360 Patent was filed on
`
`May 22, 2003. I am familiar with the technology at issue and am aware of the state
`
`of the art around this time. Based on the technology disclosed in the 360 Patent, a
`
`person of ordinary skill in the art (“POSITA”) would include someone who has a
`
`M.S. degree in Materials Science as well as at least 3-5 years of experience in the
`
`field of high temperature materials and composites. My analyses and opinions
`
`below are given from the perspective of a POSITA in these technologies in this
`
`timeframe, unless stated otherwise.
`
`
`
`4
`
`GE-1003.004
`
`

`
`II. QUALIFICATIONS AND COMPENSATION
`
`
`5.
`
`I am currently a Professor Emeritus in the Department of Materials
`
`Science and Engineering at the University of California, Berkeley (“Berkeley”) in
`
`Berkeley, California. I joined the faculty at Berkeley in 1981, where I
`
`concurrently served as Principal Investigator in the Materials Sciences Division of
`
`the Lawrence Berkeley Laboratory, and starting in 1998 as an adjunct professor in
`
`the Department of Preventative and Restorative Dental Sciences of the School of
`
`Dentistry at the University of California at San Francisco.
`
`6.
`
`I received a Bachelor of Science in Materials Science and Engineering
`
`from the Massachusetts Institute of Technology (MIT) in 1976, and a Sc.D. also in
`
`Materials Science and Engineering with an emphasis on Ceramics from MIT in
`
`1981.
`
`7.
`
`In 1981, I joined the faculty at Berkeley as an assistant professor of
`
`ceramic engineering and principal investigator (faculty scientist) in the Materials
`
`Sciences Division of the Lawrence Berkeley Laboratory. After being promoted to
`
`associate professor of ceramic engineering in 1988, I was promoted to full
`
`professor in the Department of Materials Science and Engineering in 1998. I
`
`taught ceramic processing, kinetics and phase transformations, phase diagrams,
`
`glass and crystalline ceramics, and thermodynamics for over thirty years, and
`
`supervised numerous graduate students on projects related to multiphase materials.
`
`
`
`5
`
`GE-1003.005
`
`

`
`8.
`
`Since 1981, my research and studies have consistently focused on
`
`surface and interface properties of ceramic materials and the role of surfaces and
`
`interfaces in ceramic processing, including work relevant to thermal barrier
`
`coatings. For the past twenty years, I have worked extensively on joining ceramics
`
`for high-temperature applications, both at Berkeley and with multiple groups of
`
`international colleagues. I have been the author of over 150 technical papers,
`
`many of which relate to multiphase materials and/or systems with heterophase
`
`interfaces, their processing, stability, and design. A listing of my technical papers
`
`is included in my curriculum vitae, which is attached as GE-1004. Furthermore, I
`
`am a named inventor on 3 patents that relate to transient liquid phase bonding and
`
`laser induced recrystallization of polycrystalline silicon including U.S. Patent Nos.
`
`4,379,020; 5,234,152; and 5,372,298.
`
`9.
`
`I am a member of the American Ceramic Society, where my
`
`contributions to the field resulted in being elected a Fellow of the American
`
`Ceramic Society. I also received the Richard M. Fulrath Award from the
`
`American Ceramic Society for my fundamental contributions in the area of
`
`ceramic-metal interfaces and joining. I am a member of the International
`
`Community for Composites Engineering. I have been recognized by the Japan
`
`Society for the Promotion of Science via three Invitation Fellowships for study and
`
`research in Japan.
`
`
`
`6
`
`GE-1003.006
`
`

`
`10.
`
`I serve or have in the past served on the International Editorial Boards
`
`of Diffusion and Defect Data, and the Journal of the Ceramic Society of Japan,
`
`and am currently on the International Editorial Board of High Temperature
`
`Materials and Processes and serve as an Editorial Board reviewer for Ceramics
`
`International. I, along with my colleague Dr. Antoni P. Tomsia, co-edited
`
`Ceramic Microstructures: Control at the Atomic Level.
`
`11.
`
`In addition to my work as a professor, I have also provided consulting
`
`services related to multiphase materials technology since 2001. My work as a
`
`consultant has included infringement assessments of technology concerning
`
`manufacture of multiphase materials, including the processing of ceramic-metal
`
`composite components used in microelectronics applications, prior art
`
`investigations and analyses involving composite material production, and failure
`
`and excessive wear assessments in a SiC-fiber-reinforced oxide matrix composite
`
`component.
`
`12.
`
` My time is billed at an hourly rate of $520.00. My compensation is
`
`not dependent on the substance of my statements in this Declaration.
`
`III. RELEVANT LEGAL STANDARDS
`
`
`13.
`
`I have been asked to provide my opinions regarding whether the
`
`claims of the 360 Patent are anticipated or rendered obvious by the prior art.
`
`14.
`
`I have been informed that prior art can include patents and printed
`
`
`
`7
`
`GE-1003.007
`
`

`
`publications that were published prior to the effective filing date of the 360 Patent,
`
`and that one skilled in the art should be viewed as having had knowledge of all
`
`prior art as of the date of invention for purposes of the invalidity analysis.
`
`15.
`
`I have been informed that in order for a prior art reference to
`
`anticipate a claim under 35 U.S.C. § 102, the reference must disclose every
`
`element of the claim. I understand that such disclosure can either be explicit or
`
`“inherent,” meaning necessarily present although not expressly described in the
`
`prior art reference.
`
`16.
`
`I have been informed that a claimed invention is not patentable under
`
`35 U.S.C. § 103 if the differences between the invention and the prior art are such
`
`that the subject matter as a whole would have been obvious to a person of ordinary
`
`skill in the art at the time the invention was made. I understand that I am not to use
`
`“hindsight” in making an obviousness determination, but that I must instead
`
`undertake my analysis from the perspective of one of ordinary skill in the art at the
`
`time of the alleged invention, with access to all relevant prior art. I understand that
`
`I am allowed to consider the prior art for all that it would have disclosed to me, as
`
`one of ordinary skill in the art, at the relevant time period. I also understand that
`
`the obviousness analysis takes into account factual inquiries including the level of
`
`ordinary skill in the art, the scope and content of the prior art, the differences
`
`between the prior art and the claimed subject matter, and any secondary
`
`
`
`8
`
`GE-1003.008
`
`

`
`considerations which may suggest the claimed invention was not obvious.
`
`17.
`
`I have been informed by legal counsel that the Supreme Court has
`
`recognized several rationales for combining references or modifying a reference to
`
`show obviousness of claimed subject matter. I understand some of these rationales
`
`include the following: combining prior art elements according to known methods
`
`to yield predictable results; simple substitution of one known element for another
`
`to obtain predictable results; use of a known technique to improve a similar device
`
`(method, or product) in a way; applying a known technique to a known device
`
`(method, or product) ready for improvement to yield predictable results; choosing
`
`from a finite number of identified, predictable solutions, with a reasonable
`
`expectation of success; and some teaching, suggestion, or motivation in the prior
`
`art that would have led a POSITA to modify the prior art reference or to combine
`
`prior art reference teachings to arrive at the claimed invention.
`
`18.
`
`I have also been informed that the Manual of Patent Examining
`
`Procedure provides that “[a] statement by an applicant in the specification or made
`
`during prosecution identifying the work of another as ‘prior art’ is an admission
`
`which can be relied upon for both anticipation and obviousness determinations,
`
`regardless of whether the admitted prior art would otherwise qualify as prior art
`
`under the statutory categories of 35 U.S.C. 102.” M.P.E.P. § 2129. The M.P.E.P.
`
`
`
`9
`
`GE-1003.009
`
`

`
`further states that “[w]here the specification identifies work done by another as
`
`‘prior art,’ the subject matter so identified is treated as admitted prior art.” Id.
`
`IV. BACKGROUND OF THE TECHNOLOGY
`
`A.
`
`Engine Materials: High-Temperature Oxidation Resistance
`
`19. The prior art teaches that the continuing need for engine components
`
`with high temperature, high-strength capabilities initially led the air- and spacecraft
`
`industries to investigate and develop materials, e.g., nickel-based superalloys,
`
`which have excellent oxidation resistance and mechanical properties for
`
`applications up to around 1000ºC. GE-1007.002; see also GE-1015.001(“There is
`
`increasing need for high-strength, oxidation-resistant materials for elevated
`
`temperature structural applications, particularly in aircraft gas turbines and
`
`spacecraft air frames.”). However, multiple limitations of superalloys led to the
`
`proposal of silicon-based ceramic materials, including SiC-SiC composites, for
`
`high temperature section components. GE-1007.002. Silicon-based ceramics are
`
`less dense and exhibit excellent oxidation resistance at temperatures between
`
`1000ºC and 1600ºC. GE-1007.002; see also GE-1009 at 1:25-28 (“These silicon-
`
`containing materials are particularly appealing because of their excellent high
`
`temperature properties and lower density.”), GE-1009 at 1:47-55 (“A primary
`
`advantage then of silicon-containing ceramics or silicon-containing composites . . .
`
`over metals is their superior high temperature durability which enable higher
`
`
`
`10
`
`GE-1003.010
`
`

`
`turbine rotor inlet temperatures. [Additionally], they exhibit low coefficient of
`
`thermal expansion and lower density in comparison to nickel-base superalloys.”).
`
`20.
`
`In addition to silicon-based ceramics, materials based on aluminide
`
`and silicide compositions were also actively investigated for use in high
`
`temperature engine applications. GE-1007.002 (describing the low densities, high
`
`melting points, and high thermal conductivities of aluminide and silicide matrix
`
`composites as attractive characteristics for use in high temperature environments).
`
`In particular, material composites designed around MoSi2
`
`1 were found to have high
`
`melting points and excellent high temperature oxidation resistance. GE-1007.005-
`
`.006. As described in the prior art, the intermetallic compound MoSi2 was first
`
`considered as a high temperature coating material for protecting ductile metal
`
`components in commercial heating applications. GE-1007.003. By the 1970s,
`
`silicides such as MoSi2 were also being considered as coating materials for gas
`
`turbine engine components. GE-1007.003.
`
`21. Despite its excellent oxidation resistance, the low temperature
`
`brittleness of MoSi2 limited its structural applications. GE-1007.007 (“The major
`
`problem impeding the use of MoSi2 is its mechanical properties.”). One way to
`
`overcome these problems is to create a MoSi2 composite material with a
`
`thermodynamically compatible second-phase reinforcement. GE-1007.007, .010;
`
`1 MoSi2 is an example of a refractory metal disilicide.
`
`
`
`11
`
`GE-1003.011
`
`

`
`see also GE-1016.003 (“Here the major driver for compositing [silicides] is lack of
`
`room temperature toughness rather than strength.”). “Many important ceramic
`
`reinforcements are thermodynamically stable with MoSi2.” GE-1007.005. Such
`
`ceramic reinforcements have been shown to improve the fracture toughness of
`
`MoSi2. GE-1007.011. Well before the filing of the 360 Patent, the prior art
`
`discloses that “[c]ontinual improvements were made in the mechanical properties
`
`of SiC-MoSi2 composites, through a number of generations of composite
`
`materials.” GE-1007.004 (describing that in the 1980s researchers began
`
`examining SiC-MoSi2 composites for aerospace applications).
`
`22. Before the 360 Patent, a person of ordinary skill in the art would have
`
`been aware of developments in both Si-based materials and competing candidates,
`
`such as MoSi2. As discussed below, a person of ordinary skill in the art also would
`
`have been aware of the similar problems facing the development of each of these
`
`categories of materials, including, for example, the need for increased toughness
`
`and for oxidation/environmental protection.
`
`B.
`
`Engine Materials: Environmental Barrier Coatings
`
`23. Structural components within the combustion and turbine sections of a
`
`gas turbine engine “are subject to a range of chemical attack processes, depending
`
`on the temperature, pressure, and chemical environment.” GE-1019.001. To
`
`survive these high temperature, highly oxidative environments, it has been well
`
`
`
`12
`
`GE-1003.012
`
`

`
`known that silicon-based materials, including Si, SiC, and Si3N4 ceramics, form a
`
`dense scale or coating of silica (SiO2), which acts as a barrier for the underlying
`
`silicon-containing material to prevent diffusion of O2.2 GE-1011.001; see also GE-
`
`1009 at 2:17-19; GE-1017.006; GE-1019.001. Additionally, it has been known in
`
`the art that MoSi2 similarly oxidizes to form a protective silica film of SiO2. See,
`
`e.g., GE-1015.001 (“In particular, MoSi2 . . . exhibits excellent high-temperature
`
`oxidation resistance because of the formation of a protective silica film . . . .”); GE-
`
`1012.006 (“Coatings based upon the compound MoSi2 differ from other silicides in
`
`that scale is composed of only silica.”); GE-1016.011 (“MoSi2 is known to form
`
`pure tetragonal SiO2.”); GE-1019.001 (applying conclusions “to all SiO2-protected
`
`materials [including] SiO2-forming alloys, such as molybdenum disilicide
`
`(MoSi2)”).
`
`24. Unfortunately, for these SiO2-protected materials, the protective scale
`
`deteriorates in the presence of water vapor such as steam. See, e.g., GE-1010.005
`
`
`2 In particular, this dense scale/coating inhibits the ingress of oxygen from the
`
`ambient atmosphere to the underlying silicon-based material. The silica scale,
`
`acting as a diffusion barrier for oxygen, thus reduces the rate at which the
`
`underlying silicon-based material oxidizes (i.e., forms additional SiO2), thereby
`
`extending the lifetime of the component in such environments.
`
`
`
`13
`
`GE-1003.013
`
`

`
`(describing the presence of steam as “partly a direct result of the generation of
`
`water during the combustion process, but in a number of designs it is a
`
`consequence of the use of steam injection to enhance turbine efficiency”); GE-
`
`1019.015-.016 (“It is accepted that water vapor induces devitrification in SiO2
`
`scales and accelerates the oxidation of SiC.”); GE-1020.001-.002 (listing papers
`
`that have found that water vapor accelerates oxidation of silicon carbide). In
`
`particular, silica volatilizes in the presence of steam to form gaseous SiO and
`
`Si(OH)x, ultimately resulting in the recession and material loss of the silicon-
`
`containing material itself. See GE-1011.003 (“The silica scale formed in high
`
`water vapor is porous, allowing the oxidation to propagate readily along the
`
`interface.”).
`
`25. Thus, well before the filing of the 360 Patent, it was known to those in
`
`the art that exposure to water vapor was detrimental to long-term stability, and that
`
`Si-based ceramics would need a protective coating to shield them from the harsh,
`
`water-containing environments found in gas turbine engines. See GE-1014.022
`
`(“[Environmental barrier coatings] are absolute necessity for the protection of Si-
`
`based ceramics from water vapor.”); GE-1011.001 (describing key issues for
`
`selecting an environmental barrier coating for silicon-based ceramics used in the
`
`hot section of gas turbine engines); see also GE-1001 at 1:10-18 (providing as
`
`Background to the 360 Patent that it was known that barrier layers were necessary
`
`
`
`14
`
`GE-1003.014
`
`

`
`to increase the service life of silicon-based ceramic components in gas turbine
`
`engines). Similarly, since MoSi2-containing protective coatings form a protective
`
`scale of essentially pure SiO2 (see supra ¶ 23), one of skill in the art would have
`
`known that additional protective layers were necessary to shield such coatings
`
`from environments in which water vapor was also present. See, e.g., GE-1019.001
`
`(indicating conclusions regarding the interaction of SiO2 in combustion
`
`environments also applies to MoSi2).
`
`26. Accordingly, the prior art teaches the use of barrier coatings for the
`
`protection of silicon-based ceramics from oxygen or water vapor, or both, present
`
`in the ambient atmosphere. See, e.g., GE-1014.023 (“BSAS was identified as a
`
`promising EBC candidate because of its close CTE match with Si-based
`
`ceramics…and low silica activity. . . .”); GE-1011.003 (“[A]n environmental
`
`overlay coating was necessary when protection from water vapor was needed.”),
`
`GE-1011.004 (“Replacing the YSZ top coat in the mullite/YSZ system with BSAS
`
`delayed the onset of accelerated oxidation in water vapor by a factor of at least
`
`two. . . .”); GE-1025.004 (“The development of protective coatings based on a SiC
`
`bonding layer combined with an outer yttrium silicate erosion resistant layer and
`
`oxygen barrier is described.”). It was also known that environmental barrier
`
`coatings could consist of multiple layers of different materials, where each layer
`
`could serve a variety of functions depending on its precise placement within the
`
`
`
`15
`
`GE-1003.015
`
`

`
`sequence of layers within the coating system. See, e.g., GE-1025.004 (“Thus,
`
`conventional coatings consist of multilayers of different materials designed to seal
`
`cracks by forming glassy phases on exposure to oxygen.”). In particular, the use of
`
`barium strontium aluminosilicate (BSAS) and yttrium silicate as a barrier layer was
`
`known in the art. GE-1001 at 1:10-24; GE-1011.004; GE-1013 at 2:38-46; GE-
`
`1014.023; GE-1025.004-.005.
`
`V. THE 360 PATENT
`
`A. Overview of the Claims
`
`27. The 360 Patent claims an article comprising a silicon-based substrate
`
`including an allegedly improved refractory metal disilicide/silicon eutectic alloy
`
`bond layer and an alkaline earth aluminosilicate environmental barrier layer. GE-
`
`1001 at 2:56-62. The specification provides that the silicon-based substrate, such
`
`as SiC-SiC composite, may have a refractory-metal disilicide/silicon two-phase
`
`bond coat layer made of MoSi2 and Si (listed as a preferred embodiment), which
`
`coats the Si-based substrate, and facilitates adhesion to an environmental barrier
`
`coating. Id. at 1:66-2:35. The 360 Patent claims an environmental barrier coating
`
`that is either barium strontium aluminosilicate (BSAS) or yttrium silicate (Id. at
`
`2:56-59), both of which protect the SiC composite substrate and bond coat from
`
`exposure to the ambient atmosphere. Further, the 360 Patent specification teaches
`
`that the two-phase microstructure of the proposed bond coat confers a higher
`
`
`
`16
`
`GE-1003.016
`
`

`
`resistance to fracture, as manifested in a higher fracture toughness (>1 MPa·m½).
`
`Id. at 1:66-2:3.
`
`28. Claim 1 of the 360 Patent is reproduced below. This claim includes
`
`well-known elements, including various barrier and bond layers used to form an
`
`environmental barrier coating:
`
`1. An article comprising a silicon based substrate,
`
`at least one environmental barrier layer selected from the group
`consisting essentially of an alkaline earth aluminosilicate based on
`barium and strontium, and yttrium silicate, and
`
`a bond layer between the substrate and the environmental barrier
`layer, the bond layer comprises an alloy comprising a refractory metal
`disilicide/silicon eutectic.
`
`
`
`
`
`29. Generally, refractory metals are characterized by their high melting
`
`points, strength at elevated temperatures, and good conductivity. The 360 Patent
`
`specification provides that “[p]referred refractory metals used in the bond layer of
`
`the present invention are selected from the group consisting of molybdenum,
`
`chromium, hafnium, niobium, tantalum, rhenium, titanium, tungsten, uranium,
`
`vanadium, yttrium and mixtures thereof [and] the most preferred refractory metal
`
`is molybdenum.” GE-1001 at 2:37-43. Additionally, the term eutectic describes a
`
`composition with a melting point minimum. The 360 Patent specification
`
`describes the claimed bond layer as being a “refractory metal disilicide/silicon
`
`
`
`17
`
`GE-1003.017
`
`

`
`eutectic [with] a melting point of greater than 1300º C.” Id. at 1:58-60.
`
`30. Dependent claims 2 and 3 require that the refractory metal disilicide is
`
`selected from the group consisting of disilicides of molybdenum, chromium,
`
`hafnium, niobium, rhenium, tantalum, titanium, tungsten, uranium, vanadium,
`
`yttrium and mixtures thereof. Id. at 2:63-3:5.
`
`31. Dependent claim 4 requires that the refractory metal disilicide/silicon
`
`eutectic have a melting point of greater than 1300º C. Id. at 3:6-8.
`
`32. Dependent claim 5 requires that the bond layer comprise a multiphase
`
`microstructure of the refractory metal disilicide/silicon eutectic and silicon. Id. at
`
`3:9-11. Dependent claim 6 further requires that the article of claim 5 have a
`
`fracture toughness greater than 1MPa·m½. Id. at 3:12-13.
`
`33. Dependent claim 7 requires that the bond layer comprise a multiphase
`
`microstructure of the refractory metal disilicide/silicon eutectic and refractory
`
`metal disilicide. Id. at 3:14-17. Dependent claim 8 further requires that the article
`
`of claim 7 have a fracture toughness greater than 1MPa·m½. Id. at 3:18-19.
`
`34. Dependent claim 9 requires that the bond layer comprise a multiphase
`
`microstructure of the refractory metal disilicide/silicon eutectic and one of silicon
`
`and refractory metal disilicide. Id. at 4:1-4. Dependent claim 10 further requires
`
`that the article of claim 9 have a fracture toughness greater than 1MPa·m½. Id. at
`
`4:5-6.
`
`
`
`18
`
`GE-1003.018
`
`

`
`35. Dependent claims 11 and 12 require the article of claims 1 and 9,
`
`respectively, to have silicon present in an amount greater than or equal to 66.7
`
`atomic percent. Id. at 4:7-12.
`
`36. Dependent claims 13 and 14 require the article of claims 1 and 9,
`
`respectively, to have silicon present in an amount greater than or equal to 80
`
`atomic percent. Id. at 4:13-18.
`
`B.
`
`Prosecution History
`
`37. The 360 Patent issued from U.S. Patent Application No. 10/443,342
`
`(“the 342 Application”), which was filed on May 22, 2003. Independent claim 1,
`
`as originally filed,3 is reproduced below:
`
`1. An article comprising a silicon based substrate and a bond layer,
`the bond layer comprises an alloy comprising a refractory metal
`disilicide/silicon eutectic.
`
`GE-1002.066.
`
`38.
`
`It is my understanding that during prosecution, the claims of the 342
`
`
`3 At the time of its filing, the 342 Application also included independent claim 15
`
`directed to “[a]n article comprising a silicon substrate and a bond layer, the bond
`
`layer comprising a multi-phase alloy having a fracture toughness greater than
`
`1MPa·m½.” GE-1002.067. However, claim 15 was dropped prior to issuance of
`
`the 360 Patent.
`
`
`
`19
`
`GE-1003.019
`
`

`
`Application were rejected by the examiner on two different occasions as
`
`anticipated by U.S. Patent No. 5,677,060 (“Terentieva”) (GE-1005). GE-
`
`1002.045-.048, .029-.033. In response to the first rejection, Applicant amended
`
`claim 1 to include “at least one barrier layer” over the bond layer, arguing that
`
`“[t]he present invention deals with the problem of accelerated oxidation of silica
`
`and silica forming materials and specifically with a bond layer providing between a
`
`silicon based substrate and an environmental barrier layer, the prior art does not
`
`teach, disclose, suggest or render obvious the subject matter as now claimed in
`
`independent claim 1.” GE-1002.041-.042. However, the examiner maintained his
`
`rejection of the claims in view of Terentieva, finding that Terentieva also discloses
`
`Applicant’s added limitation of a “barrier layer” because “Terentieva teaches that
`
`an outer layer may be present, such as alumina, silica, SiN, SiC, or zirconia glass.”
`
`GE-1002.032. According to the examiner, the refractory metal silicide coating
`
`layer disclosed in Terentieva “serves as an intermediate layer when the outer layer
`
`is present, and is therefore considered to effectively function as a bond layer.” Id.
`
`39. To overcome this rejection, Applicant amended claim 1 to specify that
`
`the barrier layer is an “environmental barrier layer selected from the group
`
`consisting essentially of an alkaline earth aluminosilicate based on barium and
`
`strontium, and yttrium silicate.” GE-1002.021. Applicant argued that Terentieva
`
`does not disclose “the environmental barrier layer of the present invention [which]
`
`
`
`20
`
`GE-1003.020
`
`

`
`is used to protect silicon carbide and silicon nitride from high temperature steam
`
`environments found in gas turbine engines.” Id. at .024-.025. The 342 Application
`
`received a Notice of Allowability on November 12, 2004. Id. at .012.
`
`C. Meaning of Certain Claim Terms
`
`40. For a non-expired patent, I have been informed by legal counsel that a
`
`claim subject to an IPR is interpreted in a manner that is consistent with the
`
`broadest reasonable interpretation in light of the specification. This means that the
`
`words of the claim are given their plain meaning unless that meaning is
`
`inconsistent with the specification. Below, I have provided a definition for certain
`
`claim terms consistent with the broadest reasonable interpretation in light of the
`
`specification.
`
`1. “refractory metal disilicide/silicon eutectic” (Claim 1 et al.)
`
`41. Claim 1 (and thus, all claims) of the 360 Patent requires a bond layer
`
`consisting of “an alloy comprising a refractory metal disilicide/silicon eutectic.”
`
`Generally, those of skill in the art would understand a “refractory metal” to be a
`
`metal with a melting point above 1850ºC. This melting point would limit the
`
`candidate metals to niobium, molybdenum, tantalum, tungsten, rhenium, titanium,
`
`vanadium, chromium, zirconium, hafnium, ruthenium, rhodium, osmium, and
`
`iridium. However, several of the “[p]referred refractory metals” listed in the 360
`
`Patent specification have melting points well below 1850ºC. For example,
`
`
`
`21
`
`GE-1003.021
`
`

`
`uranium and yttrium—both listed as “[p]referred refractory metals” by the 360
`
`Patent specification and in claims 2 and 3—fail to have melting points above 1850º
`
`C. Therefore, one of skill in the art would have underst