Patents by Inventor Shankar Sivaramakrishnan
Shankar Sivaramakrishnan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9803484Abstract: Articles, such as components for high temperature turbomachinery components, include one or more coatings bearing certain perovskite compositions resistant to incursion by liquid calcium-magnesium-aluminum-silicon-oxide (CMAS) materials during service. The CMAS-reactive material includes a perovskite-structured oxide, which comprises a) a rare earth element, b) niobium, tantalum or a combination of tantalum and niobium, and c) oxygen. The CMAS-reactive material is present in an effective amount to react with a CMAS composition at an operating temperature, thereby forming a reaction product having one or both of melting temperature and viscosity greater than that of the CMAS composition.Type: GrantFiled: December 19, 2014Date of Patent: October 31, 2017Assignee: General Electric CompanyInventors: Venkat Subramaniam Venkataramani, Shahana Chatterjee, Mohandas Nayak, Shankar Sivaramakrishnan
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Patent number: 9790587Abstract: An article including a substrate and a plurality of coatings disposed on the substrate is presented. The plurality of coatings includes a thermal barrier coating disposed on the substrate; and a protective coating including a calcium-magnesium-aluminum-silicon-oxide (CMAS)-reactive material disposed on the thermal barrier coating. The CMAS-reactive material has an orthorhombic weberite crystal structure. The CMAS-reactive material is present in the plurality of coatings in an effective amount to react with a CMAS composition at an operating temperature of the thermal barrier coating, thereby forming a reaction product having one or both of melting temperature and viscosity greater than that of the CMAS composition. A method of making the article and a related turbine engine component are also presented.Type: GrantFiled: October 28, 2014Date of Patent: October 17, 2017Assignee: General Electric CompanyInventors: Mohandas Nayak, Shankar Sivaramakrishnan, Venkat Subramaniam Venkataramani, Alok Mani Srivastava, Shahana Chatterjee
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Publication number: 20170165708Abstract: Provided herein are methods and compositions which allow for efficient inspection, maintenance and repair of ceramic coatings.Type: ApplicationFiled: December 9, 2015Publication date: June 15, 2017Inventors: Shankar Sivaramakrishnan, Wayne Charles Hasz, Kristen Hall Brosnan, James Edward Murphy
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Publication number: 20170145836Abstract: An article having a damage-tolerant thermal barrier coating includes a plurality of coating layers disposed over a substrate. The plurality of coatings comprises an inner layer and an outer layer. The outer layer is more resistant to infiltration by nominal CMAS relative to 8 weight percent yttria-stabilized zirconia at a temperature of 1300 degrees Celsius. The inner layer has, in a temperature range from about 1000 degrees Celsius to about 1200 degrees Celsius, a thermal resistance in a range from about 9×10?5 degree Kelvin per watt to about 23×10?5 degree Kelvin per watt.Type: ApplicationFiled: November 24, 2015Publication date: May 25, 2017Inventors: Shankar Sivaramakrishnan, Larry Steven Rosenzweig
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Publication number: 20170101875Abstract: A method for coating a surface of a substrate is provided. The method includes providing a suspension or a precursor comprising feedstock material suspended in a liquid medium. Further, the method includes spraying the suspension or the precursor onto the surface at a spray angle less than about 75 degrees to a tangent of the surface.Type: ApplicationFiled: December 20, 2016Publication date: April 13, 2017Inventors: Larry Steven Rosenzweig, James Anthony Ruud, Shankar Sivaramakrishnan
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Patent number: 9556505Abstract: A coating comprising a first surface and a second surface is provided. The coating includes a plurality of growth domains. An orientation of at least one growth domain of the plurality of growth domains is non-vertical with respect to the first surface of the coating. One or more growth domains of the plurality of growth domains comprise a plurality of at least partially melted and solidified particles.Type: GrantFiled: August 31, 2012Date of Patent: January 31, 2017Assignee: General Electric CompanyInventors: Larry Steven Rosenzweig, James Anthony Ruud, Shankar Sivaramakrishnan
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Publication number: 20160177746Abstract: Articles, such as components for high temperature turbomachinery components, include one or more coatings bearing certain perovskite compositions resistant to incursion by liquid calcium-magnesium-aluminum-silicon-oxide (CMAS) materials during service. The CMAS-reactive material includes a perovskite-structured oxide, which comprises a) a rare earth element, b) niobium, tantalum or a combination of tantalum and niobium, and c) oxygen. The CMAS-reactive material is present in an effective amount to react with a CMAS composition at an operating temperature, thereby forming a reaction product having one or both of melting temperature and viscosity greater than that of the CMAS composition.Type: ApplicationFiled: December 19, 2014Publication date: June 23, 2016Inventors: Venkat Subramaniam Venkataramani, Shahana Chatterjee, Mohandas Nayak, Shankar Sivaramakrishnan
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Publication number: 20160168684Abstract: Articles having coatings that are resistant to high temperature degradation are described, along with methods for making such articles. The article comprises a coating disposed on a substrate. The coating comprises a plurality of elongated surface-connected voids. The article further includes a protective agent disposed within at least some of the voids of the coating; the protective agent comprises a substance capable of chemically reacting with liquid nominal CMAS to form a solid crystalline product outside the crystallization field of said nominal CMAS. This solid crystalline product has a melting temperature greater than about 1200 degrees Celsius. The method generally includes disposing the protective agent noted above within the surface connected voids of the coating at an effective concentration to substantially prevent incursion of CMAS materials into the voids in which the protective agent is disposed.Type: ApplicationFiled: December 12, 2014Publication date: June 16, 2016Inventors: Kristen Hall Brosnan, Shahana Chaterjee, Wayne Charles Hasz, Mohandas Nayak, Digamber Gurudas Porob, Gopi Chandran Ramachandran, Larry Steven Rosenzweig, Shankar Sivaramakrishnan, Alok Mani Srivastava, Venkat Subramaniam Venkataramani
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Publication number: 20160115819Abstract: An article including a substrate and a plurality of coatings disposed on the substrate is presented. The plurality of coatings includes a thermal barrier coating disposed on the substrate; and a protective coating including a calcium-magnesium-aluminum-silicon-oxide (CMAS)-reactive material disposed on the thermal barrier coating. The CMAS-reactive material has an orthorhombic weberite crystal structure. The CMAS-reactive material is present in the plurality of coatings in an effective amount to react with a CMAS composition at an operating temperature of the thermal barrier coating, thereby forming a reaction product having one or both of melting temperature and viscosity greater than that of the CMAS composition. A method of making the article and a related turbine engine component are also presented.Type: ApplicationFiled: October 28, 2014Publication date: April 28, 2016Inventors: Mohandas Nayak, Shankar Sivaramakrishnan, Venkat Subramaniam Venkataramani, Alok Mani Srivastava, Shahana Chatterjee
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Publication number: 20160115818Abstract: An article including a substrate and a plurality of coatings disposed on the substrate is presented. The plurality of coatings includes a thermal barrier coating disposed on the substrate; and a protective coating including a calcium-magnesium-aluminum-silicon-oxide (CMAS)-reactive material disposed on the thermal barrier coating. The CMAS-reactive material includes an NZP-type material. The CMAS-reactive material is present in the plurality of coatings in an effective amount to react with a CMAS composition at an operating temperature of the thermal barrier coating, thereby forming a reaction product having one or both of melting temperature and viscosity greater than that of the CMAS composition. A method of making the article and a related turbine engine component are also presented.Type: ApplicationFiled: October 27, 2014Publication date: April 28, 2016Inventors: Digamber Gurudas Porob, Shankar Sivaramakrishnan, Venkat Subramaniam Venkataramani, Mohandas Nayak, Gopi Chandran Ramachandran
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Patent number: 9249514Abstract: An article and method of forming the article are disclosed. The article includes a substrate, an overlay bond coat deposited over the substrate and a topcoat deposited over the bond coat. The bond coat of the article includes a plasma affected region proximate to an interface between the bond coat and the topcoat, and the plasma affected region includes an elongated intergranular phase. The method of depositing includes adjusting the plasma spray conditions so as to form the plasma affected region proximate to an interface between the bond coat and the topcoat, and elongated intergranular phases in the plasma affected regions.Type: GrantFiled: August 31, 2012Date of Patent: February 2, 2016Assignee: General Electric CompanyInventors: Shankar Sivaramakrishnan, James Anthony Ruud, Curtis Alan Johnson, Larry Steven Rosenzweig
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Publication number: 20150167141Abstract: The present application provides Calcia-Magnesia-Alumina-Silica (CMAS) (or molten silicate) resistant thermal barrier coatings (TBC). The coatings include elongate growth domains of non-equiaxed, randomly arranged overlapping grains or splats. The elongate growth domains include overlapping individual, randomly distributed splats of tough and soft phases. In some embodiments, the elongate growth domains are formed via air plasma spray. In some embodiments, the tough phases are at least partially stabilized zirconia and/or hafnia compositions, and the soft phases are CMAS (or molten silicate) reactive or resistant compositions. Within each elongate growth domain, the mixture of the tough and soft phases act together to limit penetration of CMAS and also provide sufficient domain toughness to minimize cracking forces produced during crystallization of infiltrated CMAS.Type: ApplicationFiled: December 16, 2013Publication date: June 18, 2015Applicant: GENERAL ELECTRIC COMPANYInventors: Larry Steven ROSENZWEIG, James Anthony RUUD, Shankar SIVARAMAKRISHNAN
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Publication number: 20150159507Abstract: Articles for high temperature service, especially where enhanced strain tolerance coupled with resistance to ingested dust and debris (CMAS) is desirable, are provided herein. The article comprises a substrate and a multi-layered coating system disposed over the substrate. The coating system comprises a first layer comprising a first material and a second layer comprising a second material, with the first layer disposed between the second layer and the substrate. The second material is more resistant to infiltration by a nominal CMAS composition relative to 8 weight percent yttria-stabilized zirconia at a temperature of 1300 degrees Celsius. The second layer comprises a plurality of through-thickness cracks, wherein at least 90 percent of the cracks have a mean crack opening displacement, measured in a distal surface region, of up to about 5 micrometers.Type: ApplicationFiled: December 6, 2013Publication date: June 11, 2015Applicant: GENERAL ELECTRIC COMPANYInventors: Shankar Sivaramakrishnan, Lauraine Denault, Larry Steven Rosenzweig
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Publication number: 20150140353Abstract: An article and method of forming the article are disclosed. The article includes a substrate, an overlay bond coat deposited over the substrate and a topcoat deposited over the bond coat. The bond coat of the article includes a plasma affected region proximate to an interface between the bond coat and the topcoat, and the plasma affected region includes an elongated intergranular phase. The method of depositing includes adjusting the plasma spray conditions so as to form the plasma affected region proximate to an interface between the bond coat and the topcoat, and elongated intergranular phases in the plasma affected regions.Type: ApplicationFiled: August 31, 2012Publication date: May 21, 2015Applicant: GENERAL ELECTRIC COMPANYInventors: Shankar Sivaramakrishnan, James Anthony Ruud, Curtis Alan Johnson, Larry Steven Rosenzweig
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Publication number: 20140065361Abstract: A coating comprising a first surface and a second surface is provided. The coating includes a plurality of growth domains. An orientation of at least one growth domain of the plurality of growth domains is non-vertical with respect to the first surface of the coating. One or more growth domains of the plurality of growth domains comprise a plurality of at least partially melted and solidified particles.Type: ApplicationFiled: August 31, 2012Publication date: March 6, 2014Applicant: GENERAL ELECTRIC COMPANYInventors: Larry Steven Rosenzweig, James Anthony Ruud, Shankar Sivaramakrishnan