Sylvia L Johnson

US Patent:

8409491, Apr 2, 2013

Filed:

Aug 22, 2011

Appl. No.:

13/215206

Inventors:

Margaret M Stackpoole - Santa Clara CA, US
Matthew J Gasch - Sacramento CA, US
Michael W Olson - Sunnyvale CA, US
Ian W. Hamby - Seattle WA, US
Sylvia M Johnson - Piedmont CA, US

Assignee:

The United States of America as Represented by the Administrator of the National Aeronautics & Space Administration (NASA) - Washington DC

International Classification:

B28B 1/00
B28B 3/00
B28B 5/00
C04B 33/32
C04B 35/00
B32B 9/00
B32B 19/00

US Classification:

264624, 264625, 264626, 428698, 428699, 501 952, 501 962

Abstract:

A tough ultra-high temperature ceramic (UHTC) composite comprises grains of UHTC matrix material, such as HfB, ZrBor other metal boride, carbide, nitride, etc. , surrounded by a uniform distribution of acicular high aspect ratio reinforcement ceramic rods or whiskers, such as of SiC, is formed from uniformly mixing a powder of the UHTC material and a pre-ceramic polymer selected to form the desired reinforcement species, then thermally consolidating the mixture by hot pressing. The acicular reinforcement rods may make up from 5 to 30 vol % of the resulting microstructure.

US Patent:

20020011439, Jan 31, 2002

Filed:

Feb 28, 2001

Appl. No.:

09/794332

Inventors:

Yigal Blum - San Jose CA, US
Sylvia Johnson - Piedmont CA, US
Huiyong Chen - San Jose CA, US

International Classification:

B01D039/20
B05D003/02
B05D005/00

US Classification:

210/490000, 210/510100, 427/376200, 427/243000

Abstract:

A Porous ceramic filter and its method of production are disclosed. The ceramic filter has at least one porous layer (or skin) made of a binder formed of a cured ceramic powder and a preceramic or pyrolyzed ceramic precursor optionally containing a source of zirconia. In some embodiments, the binder is formed of the zirconia source only. The presence of the zirconia gives a skin with good mechanical strength and corrosion resistance to both acidic and basic solutions.

US Patent:

56352506, Jun 3, 1997

Filed:

May 9, 1995

Appl. No.:

8/437722

Inventors:

Yigal D. Blum - San Jose CA
Sylvia M. Johnson - Piedmont CA
Michael I. Gusman - Palo Alto CA

Assignee:

SRI International - Menlo Park CA

International Classification:

B05D 302

US Classification:

427387

Abstract:

A method is provided for preparing ceramic precursors from hydridosiloxane starting materials and then pyrolyzing these precursors to give rise to silicious ceramic materials. Si--H bonds present in the hydridosiloxane starting materials are catalytically activated, and the activated hydrogen atoms may then be replaced with nonhydrogen substituents. These preceramic materials are pyrolyzed in a selected atmosphere to give the desired ceramic product. Ceramic products which may be prepared by this technique include silica, silicon oxynitride, silicon carbide, metal silicates, and mullite.

US Patent:

49754157, Dec 4, 1990

Filed:

Jul 10, 1987

Appl. No.:

7/071977

Inventors:

Michael I. Gusman - Palo Alto CA
Sylvia M. Johnson - Piedmont CA

Assignee:

SRI - International - Menlo Park CA

International Classification:

C01F 1700
C01G 302

US Classification:

505 1

Abstract:

The present invention pertains to a method of preparing particles of superconducting ceramic powders, which method comprises: (a) dissolving the soluble salts of the cations in aqueous medium; (b) obtaining a solution having pH of between about 4 and 7 by optionally treating the aqueous medium with ammonia, or ammonium hydroxide; (c) atomizing the solution of step (b) onto liquid nitrogen at about -196. degree. C. ; (d) removing the liquid nitrogen by evaporation; (e) removing the water by sublimation at reduced pressure; (f) heating the solid residue of step (e) at 40-60. degree. C. at reduced pressure; (g) calcining the solid residue in flowing oxygen or air at temperature of between about 200. degree. to 895. degree. C. ; and (h) cooling the solid at a temperature of between about 900. degree. C. and ambient temperature in sufficient air or oxygen and recovering the superconducting powder having an average diameter of between about 0.

US Patent:

51225050, Jun 16, 1992

Filed:

Oct 1, 1990

Appl. No.:

7/591036

Inventors:

Michael Gusman - Palo Alto CA
Gilbert Tong - Union City CA
Angel Sanjurjo - San Jose CA
Sylvia M. Johnson - Piedmont CA
Robert Lamoreaux - San Jose CA

Assignee:

SRI International - Menlo Park CA

International Classification:

H01L 3912

US Classification:

505 1

Abstract:

The present invention relates to an improved process to produce an essentially carbon-free nitrate of an alkali metal, alkaline earth metal, transition metal, lanthanide metal, actinide metal, metal, or mixtures thereof, which process comprises: Contacting an anhydrous composition of an alkali metal, alkaline earth metal, transition metal, lanthanide metal, actinide metal, or mixtures thereof substituted with an organic or an inorganic carbon-containing substitute with flowing nitrogen dioxide, dinitrogen tetroxide or mixtures thereof at a temperature of between about 40. degree. to 150. degree. C. under anhydrous conditions for a time and at a pressure effective to form the nitrate of the alkaline metal, alkaline earth metal, transition metal, lanthanide metal, actinide metal, or mixtures thereof, essentially free of any carbon containing contaminant. Materials produced by this improved process are useful as electrical superconductors, e. g. YBa. sub. 2 Cu. sub. 3 O. sub. 7, or as high performance advanced materials, e. g. BaTiO. sub.

US Patent:

48866520, Dec 12, 1989

Filed:

Apr 22, 1988

Appl. No.:

7/185132

Inventors:

Gopala Krishnan - Sunnyvalle CA
Michael Gusman - Palo Alto CA
Sylvia M. Johnson - Piedmont CA
David J. Rowcliffe - Stockholm, SE
Hajime Nakano - Osaka, JP

Assignee:

Osaka Gas Co., Ltd. - Osaka

International Classification:

C01B 3130
C01B 3136

US Classification:

423439

Abstract:

Production of carbide shapes of silicon, titanium or vanadium by reaction of carbon with the metal in liquid phase such being carried out by heating a mixture of particles of carbon and particles of the metal rapidly to the melting point of the metal, thereby minimizing solid state reaction, and holding at a temperature and for a time sufficient to cause reaction. The metal and carbon particles are about 0. 05 to 10 mm in diameter. An organic binder is used which volatilizes or dissociates upon heating.