Natraj C Iyer

US Patent:

47235896, Feb 9, 1988

Filed:

May 19, 1986

Appl. No.:

6/864611

Inventors:

Natraj C. Iyer - Monroeville PA
Alan T. Male - Murrysville PA

Assignee:

Westinghouse Electric Corp. - Pittsburgh PA

International Classification:

B22D 2300

US Classification:

164 46

Abstract:

A low pressure plasma or laser spray metal deposition process for the manufacture of a vacuum interrupter contact with a tailored composition gradient through the thickness of the contact.

US Patent:

51209187, Jun 9, 1992

Filed:

Nov 19, 1990

Appl. No.:

7/615109

Inventors:

Robert L. Thomas - Horseheads NY
Natraj C. Iyer - Columbia SC
Allan J. Bamford - late of Horseheads NY

Assignee:

Westinghouse Electric Corp. - Pittsburgh PA

International Classification:

H01H 3366

US Classification:

200144B

Abstract:

Copper-chromium contacts and copper-ferrous material shields are used in vacuum circuit interrupters. The copper chromium contacts include a specific copper-iron non-abutting section, and an abutting layer preferably of copper-chromium with a layer thickness that constitutes about 50% of the total thickness of the contact which constitutes the abutting section of the contact structure. The shield for the contacts, are preferably formed of copper-ferrous material and "X" in which 1%-50% is ferrous material, and "X"=chromium 0% to 30% and ferrous material plus "X" is less than 60% of the total shield. The contacts and shields are formed by a powder metallurgical procedure.

US Patent:

51686201, Dec 8, 1992

Filed:

Nov 15, 1990

Appl. No.:

7/614796

Inventors:

Paul E. Denney - State College PA
Natraj C. Iyer - Columbia SC
William F. Hannan - Monroeville Boro PA

Assignee:

Westinghouse Electric Corp. - Pittsburgh PA

International Classification:

H01R 4304

US Classification:

29597

Abstract:

A composite brush to shunt attachment wherein a volatile component of a composite but mostly metallic brush, used for current collection purposes, does not upon welding or brazing, adversely affect the formation of the interfacial bond with a conductive shunt which carries the current from the zone of the brush. The brush to shunt attachment for a brush material of copper-graphite composite and a shunt of copper, or substituting silver for copper as an alternative, is made through a hot isostatic pressing (HIP). The HIP process includes applying high pressure and temperature simultaneously at the brush to shunt interface, after it has been isolated or canned in a metal casing in which the air adjacent to the interface has been evacuated and the interfacial area has been sealed before the application of pressure and temperature.

US Patent:

47662743, Aug 23, 1988

Filed:

Jan 25, 1988

Appl. No.:

7/147420

Inventors:

Natraj C. Iyer - Monroeville PA
Alan T. Male - Murrysville Borough PA
Sidney J. Cherry - Elmira NY
Robert E. Gainer - Monroeville Boro. PA

Assignee:

Westinghouse Electric Corp. - Pittsburgh PA

International Classification:

H01H 3366

US Classification:

200144B

Abstract:

A powdered metallurgical procedure for forming chromium copper contacts used in vacuum circuit interrupters, in which prealloyed powder formed by mixing to copper, chromium of between two to thirty-seven weight percent is rapidly solidified after melting at about 1100. degree. C. to 1500. degree. C. This powder may be blended with additional chromium of between 12 to 50 weight percent with a maximum of fifty-five weight percent of chromium in the final contact structure. This blended mixture may then be either (i) cold pressed at 100,000 psig. and vacuum sintered at 800. degree. to 1400. degree. C. ; or (ii) be subjected to hot isostatic pressure of 10,000 to 30,000 psig. at between 700. degree. C. to 1080. degree. C. ; or (iii) containing the blended copper-chromium powder and the additional chromium powder into an evacuated can and hot extruding the can between 400. degree. C. to 900. degree. C. , to form the contacts.

US Patent:

49098411, Mar 20, 1990

Filed:

Jun 30, 1989

Appl. No.:

7/374330

Inventors:

Natraj C. Iyer - Monroeville PA
Alan T. Male - Murrysville Boro PA
William R. Lovic - New Kensington PA

Assignee:

Westinghouse Electric Corp. - Pittsburgh PA

International Classification:

C22C 2912

US Classification:

75233

Abstract:

A process of hot pressing of materials to form articles or compacts is characterized by the steps: (A) providing a compactable particulate mixture; (B) uniaxially pressing the particles without heating to provide article or compact (22); (C) placing at least one article or compact (22) in an open pan (31) having an insertable frame (32) with edge surfaces (34) that are not significantly pressure deformable, where the inside side surfaces of the frame are parallel to the central axis B--B of the open pan, and where each article or compact is surrounded by fine particles of a separating material; (D) evacuating air from the container and sealing the articles or compacts inside the container by means of top lid (36); (E) hot pressing the compacts at a pressure from 352. 5 kg/cm. sup. 2 to 3,172 kg/cm. sup. 2 to provide simultaneous hot pressing and densification of the articles or compacts; (F) gradually cooling and releasing the pressure; and, (G) separating the articles or compacts from the container, where there is no heating of the compacts in the process before step (E).

US Patent:

48102890, Mar 7, 1989

Filed:

Apr 4, 1988

Appl. No.:

7/177274

Inventors:

Norman S. Hoyer - Mt. Lebanon PA
Natraj C. Iyer - Monroeville PA

Assignee:

Westinghouse Electric Corp. - Pittsburgh PA

International Classification:

C22C 2912

US Classification:

75232

Abstract:

A process of hot isostatic pressing of powders to form electrical contacts is characterized by the steps: (A) mixing powders, 1 in the Drawing, from metal containing powder or metal containing powder plus carbon powder, where at least one of Ag and Cu is present, (B) thermal cleaning treatment of the powder, 2 in the Drawing, (C) granulating the thermally treated powder, 3 in the Drawing, (D) uniaxially pressing the powders without heating, 5 in the Drawing, to provide a compact, (E) placing at least one compact in a pressure-transmitting, pressure-deformable container, 6 in the Drawing, and surrounding each compact with fine particles of a separating material, (F) evacuating air from the container, 7 in the Drawing, (G) sealing the compacts inside the container, 8 in the Drawing, (H) hot isostatic pressing, 9 in the Drawing, the compacts through the pressure transmitting material at a pressure from 352 kg/cm. sup. 2 to 2,115 kg/cm. sup. 2 and a temperature from 0. 5. degree. C. to 100. degree. C.

US Patent:

49784870, Dec 18, 1990

Filed:

Jan 13, 1989

Appl. No.:

7/296654

Inventors:

Elmer E. Eiffler - Glenshaw PA
Natraj C. Iyer - Monroeville PA
Alan T. Male - Murrysville PA
David J. Boes - Monroeville PA

Assignee:

Westinghouse Electric Corp. - Pittsburgh PA

International Classification:

B05D 312

US Classification:

264 60

Abstract:

An annular chromium carbide coating on an annular sealing surface of a stainless steel sealing assembly component for use in a nuclear reactor coolant pump, is treated by encasing at least the chromium carbide coating on the stainless steel sealing surface by applying a metallic cover thereover, evacuating the atmosphere between the cover and the coating on the sealing surface, hot isostatic pressing the stainless steel sealing assembly component and the chromium carbide coating thereon encased by the cover, cooling the sealing assembly component and the coating thereon encased by the cover, and after cooling thereof removing the cover from the coating. The result is a chromium carbide coating on the sealing component substrate densified substantially to its full theoretical density (greater than 99%) and metallurgically bonded by the hot isostatic pressing to the substrate exterior surface.

US Patent:

49279858, May 22, 1990

Filed:

Aug 12, 1988

Appl. No.:

7/231040

Inventors:

Natraj C. Iyer - Monroeville PA
Walter J. Carr - Wilkins Twp., Allegheny County PA
Alan T. Male - Murrysville PA

Assignee:

Westinghouse Electric Corp. - Pittsburgh PA

International Classification:

H01B 1200

US Classification:

1741251

Abstract:

A composite hyperconductor for use at cryogenic temperatures and particularly well suited for AC applications employs at least one filament of conductor having an extremely low electrical resistance at cryogenic temperatures, a strengthening matrix surrounding the conductor, and a barrier for electrically insulating the conductor from the matrix while providing for efficient heat transfer therebetween and/or serving as a diffusion barrier to prevent contamination of the high purity conductor during processing. The preferred composite hyperconductor for space applications comprises an ultra high purity aluminum conducting filament, a aluminum alloy matrix and a boron nitride barrier.