Bhupendra K Gupta

US Patent:

6434823, Aug 20, 2002

Filed:

Oct 10, 2000

Appl. No.:

09/685262

Inventors:

Bhupendra Kumar Gupta - Cincinnati OH
Wayne Ray Grady - Fairfield OH
Nripendra Nath Das - West Chester OH

Assignee:

General Electric Company - Schenectady NY

International Classification:

B23P 1500

US Classification:

298891, 298897, 2940218

Abstract:

A method is provided for repairing an article having a fissure in a metallic overlay environmental resistant coating that includes the element Al, for example an overlay coating of the MCrAlY type. The method depletes more than about 90 wt. % of the Al from an exposed coating surface within the fissure and from a coating outer surface adjacent the fissure, to a depth of at least about 7 mils, without removal of the coating and while substantially maintaining the coating thickness. Thereafter, the fissure is repaired.

US Patent:

6440496, Aug 27, 2002

Filed:

Jan 19, 2000

Appl. No.:

09/487103

Inventors:

Bhupendra K. Gupta - Cincinnati OH
Thomas E. Mantkowski - Madeira OH
Nripendra N. Das - West Chester OH
Raymond W. Heidorn - Fairfield OH

Assignee:

General Electric Company - Schenectady NY

International Classification:

C23C 1606

US Classification:

427252, 42725531, 4272557

Abstract:

A thermal barrier coating system and a method for forming the coating system on a component designed for use in a hostile thermal environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The coating system includes a diffusion aluminide bond coat whose oxide growth rate is significantly reduced to improve the spallation resistance of a thermal barrier layer by forming the bond coat to include a dispersion of aluminum, chromium, nickel, cobalt and/or platinum group metal oxides. The oxides preferably constitute about 5 to about 20 volume percent of the bond coat. A preferred method of forming the bond coat is to initiate a diffusion aluminizing process in the absence of oxygen to deposit a base layer of diffusion aluminide, and then intermittently introduce an oxygen-containing gas into the diffusion aluminizing process to form within the bond coat the desired dispersion of oxides. Thereafter, a ceramic layer is deposited on the bond coat to form a thermal barrier coating.

US Patent:

6465040, Oct 15, 2002

Filed:

Feb 6, 2001

Appl. No.:

09/777636

Inventors:

Bhupendra Kumar Gupta - Cincinnati OH
Nripendra Nath Das - West Chester OH
Lyle Timothy Rasch - Fairfield OH
Jeffrey Allen Conner - Hamilton OH
Michael James Weimer - Loveland OH

Assignee:

General Electric Company - Schenectady NY

International Classification:

B05D 312

US Classification:

427142, 427140, 427242, 427328, 427307, 427309

Abstract:

A method is provided for refurbishing a service operated metallic coating on a substrate alloy, the coating including at least within a coating outer surface at least one oxide chemically grown from at least one coating element, for example Al, and chemically bonded with the coating outer surface as a result of thermal exposure during service operation. Growth of the oxide has depleted at least a portion of the coating element from the coating. The method comprises removing the oxide from the coating outer surface while substantially retaining the metallic coating, thereby exposing in the coating outer surface at least one surface void that had been occupied by the oxide. The retained metallic coating is mechanically worked, substantially without removal of the retained coating, to close the void, providing a treated metallic coating surface over which a refurbishing coating is applied. In one form, the mechanical working provides, concurrently, a compressive stress in the substrate alloy beneath the metallic coating.

US Patent:

6503574, Jan 7, 2003

Filed:

Dec 22, 1994

Appl. No.:

08/362050

Inventors:

David William Skelly - Burnt Hills NY
Bangalore Aswatha Nagaraj - West Chester OH
David John Wortman - Hamilton OH
David Vincent Rigney - Cincinnati OH
Seetha Ramaiah Mannava - Cincinnati OH
Rudolfo Viguie - Cincinnati OH
Robert William Bruce - Loveland OH
Warren Arthur Nelson - Cincinnati OH
Curtis Alan Johnson - Schenectady NY
Bhupendra Kumar Gupta - Cincinnati OH

Assignee:

General Electric Co. - Schnectedy NY

International Classification:

B32B 904

US Classification:

427446, 4272481, 427292, 427556, 427250, 427309, 427585, 427258, 427327, 427596, 427264, 427328, 427270, 427405, 427275, 427422, 427287, 427427

Abstract:

An article having a substrate is protected by a thermal barrier coating system. An interfacial layer contacts the upper surface of the substrate. The interfacial layer may comprise a bond coat only, or a bond coat and an overlay coat. The interfacial layer has on its upper surface a preselected, controllable pattern of three-dimensional features, such as grooves in a parallel array or in two angularly offset arrays. The features are formed by an ablation process using an ultraviolet laser such as an excimer laser. A ceramic thermal barrier coating is deposited over the pattern of features on the upper surface of the interfacial layer.

US Patent:

6555179, Apr 29, 2003

Filed:

Mar 17, 2000

Appl. No.:

09/527270

Inventors:

Jim D. Reeves - Cincinnati OH
Bhupendra K. Gupta - Cincinnati OH
Nripendra N. Das - West Chester OH

Assignee:

General Electric Company - Schenectady NY

International Classification:

C23C 406

US Classification:

427454, 427456, 427252, 427253

Abstract:

A thermal barrier coating system and a method for forming the coating system on an article designed for use in a hostile thermal environment. The method is particularly directed to a coating system that includes a plasma-sprayed MCrAlY bond coat on which a thermal-insulating APS ceramic layer is deposited, in which the oxidation resistance of the bond coat and the spallation resistance of the ceramic layer are substantially increased by vapor phase aluminizing the bond coat. The bond coat is deposited to have a surface area ratio of at least 1. 4 and a surface roughness of at least 300 inch Ra in order to promote the adhesion of the ceramic layer. The bond coat is then overcoat aluminized using a vapor phase process that does not alter the surface area ratio of the bond coat. This process is carried out at relatively low temperatures that promote inward diffusion of aluminum relative to outward diffusion of the bond coat constituents, particularly nickel and other refractory elements. The process conditions also provide sufficient vapor phase activity at the surface of the bond coat that promote aluminum atomic movement through the bond coat.

US Patent:

6800376, Oct 5, 2004

Filed:

Sep 30, 2002

Appl. No.:

10/262113

Inventors:

Bhupendra Kumar Gupta - Cincinnati OH
Nripendra Nath Das - West Chester OH
Lyle Timothy Rasch - Fairfield OH
Jeffrey Allen Conner - Hamilton OH
Michael James Weimer - Loveland OH

Assignee:

General Electric Company - Schenectady NY

International Classification:

B32B 1500

US Classification:

428612, 428632, 428650, 428679, 428680, 428681, 416241 R

Abstract:

A method is provided for refurbishing a service operated metallic coating on a substrate alloy, the coating including at least within a coating outer surface at least one oxide chemically grown from at least one coating element, for example Al, and chemically bonded with the coating outer surface as a result of thermal exposure during service operation. Growth of the oxide has depleted at least a portion of the coating element from the coating. The method comprises removing the oxide from the coating outer surface while substantially retaining the metallic coating, thereby exposing in the coating outer surface at least one surface void that had been occupied by the oxide. The retained metallic coating is mechanically worked, substantially without removal of the retained coating, to close the void, providing a treated metallic coating surface over which a refurbishing coating is applied. In one form, the mechanical working provides, concurrently, a compressive stress in the substrate alloy beneath the metallic coating.

US Patent:

6892931, May 17, 2005

Filed:

Dec 27, 2002

Appl. No.:

10/330420

Inventors:

Marek Steplewski - Pharr TX, US
Bhupendra K. Gupta - Cincinnati OH, US

Assignee:

General Electric Company - Schenectady NY

International Classification:

B23K031/02

US Classification:

228119, 228170, 228182, 2940216, 29889

Abstract:

A method facilitates replacing a portion of a gas turbine engine turbine support. The turbine support includes a body including a forward leg, an aft leg, and a mounting flange that each extend radially outwardly from the body. The forward leg is axially upstream from the aft leg and the mounting flange. The mounting flange is substantially axially aligned with respect to the aft leg. The method comprises cutting through at least one of the body, the aft leg, and the mounting flange, removing the forward leg and at least a portion of the body that is upstream from the cut from the engine, and coupling a replacement spad to the portion of the turbine support that is downstream from the cut.

US Patent:

7060366, Jun 13, 2006

Filed:

Feb 19, 2003

Appl. No.:

10/371744

Inventors:

Bhupendra Kumar Gupta - Cincinnati OH, US
Wayne Ray Grady - Fairfield OH, US
Lyle Timothy Rasch - Fairfield OH, US
Thomas Joseph Kelly - Cincinnati OH, US
Nripendra Nath Das - West Chester OH, US

Assignee:

General Electric Company - Schenectady NY

International Classification:

B32B 15/04
F03B 3/12

US Classification:

428632, 428679, 428680, 428666, 428650, 416241 R

Abstract:

A coated article has a metallic substrate with a substrate composition, and a metallic coating overlying and contacting the metallic substrate. The metallic coating has a metallic-coating composition different from the substrate composition. A protective coating overlies and contacts the metallic coating. The protective coating includes a chromium aluminide layer overlying and contacting the metallic coating, and optionally a thermal barrier coating overlying and contacting the chromium aluminide layer. This structure may be used to restore a key dimension of an article that has previously been in service and to protect the article as well.