Patents by Inventor Stephen Chwastiak
Stephen Chwastiak 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: 5945062Abstract: The invention includes a process for producing a reaction bonded silicon carbide composite reinforced with coated silicon carbide fibers which is suitable for high temperature applications. The process includes the steps of coating SiC fibers with AlN, BN or TiB.sub.2 ; treating the coated fibers with a mixture of SiC powder, water and a surfactant; preparing a slurry comprising SiC powder and water; infiltrating the coated fibers with the slurry to form a cast; drying the cast to form a green body; and reaction bonding the green body to form a dense SiC fiber reinforced reaction bonded matrix composite.The invention further includes a SiC fiber reinforced SiC composite comprising a reaction bonded SiC matrix, a SiC fiber reinforcement possessing thermal stability at high temperatures and an interface coating on the fibers having chemical and mechanical compatibility with the SiC matrix and with the SiC fibers.Type: GrantFiled: February 17, 1998Date of Patent: August 31, 1999Assignee: The Carborundum CompanyInventors: Stephen Chwastiak, Sai-Kwing Lau, Carl H. McMurtry, Gajawalli V. Srinivasan
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Patent number: 5871685Abstract: Provided is a fast and efficient method of burnishing a brake pad. The brake pad is contacted with a heat source having a power density greater than about 270 Mw/m.sup.2. Also provided is pre-burnished brake pad having an increased coefficient of friction.Type: GrantFiled: February 17, 1995Date of Patent: February 16, 1999Assignee: Performance Friction Corp.Inventors: Stephen Chwastiak, Jens H. S. Lamba, Donald L. Burgoon
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Patent number: 5817432Abstract: The invention includes a process for producing a reaction bonded silicon carbide composite reinforced with coated silicon carbide fibers which is suitable for high temperature applications. The process includes the steps of coating SiC fibers with AlN, BN or TiB.sub.2 ; treating the coated fibers with a mixture of SiC powder, water and a surfactant; preparing a slurry comprising SiC powder and water; infiltrating the coated fibers with the slurry to form a cast; drying the cast to form a green body; and reaction bonding the green body to form a dense SiC fiber reinforced reaction bonded matrix composite.The invention further includes a SiC fiber reinforced SiC composite comprising a reaction bonded SiC matrix, a SiC fiber reinforcement possessing thermal stability at high temperatures and an interface coating on the fibers having chemical and mechanical compatibility with the SiC matrix and with the SiC fibers.Type: GrantFiled: August 16, 1996Date of Patent: October 6, 1998Assignee: The Carborundum CompanyInventors: Stephen Chwastiak, Sai-Kwing Lau, Carl H. McMurtry, Gajawalli V. Srinivasan
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Patent number: 5693402Abstract: Provided is a pre-burnished brake pad that has been contacted with a heat source having a power in the range of 250 Mw/m.sup.2 to about 500 Mw/m.sup.2.Type: GrantFiled: August 29, 1995Date of Patent: December 2, 1997Assignee: Performance Friction CorporationInventors: Stephen Chwastiak, Jens H. S. Lamba, Donald L. Burgoon
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Patent number: 5643514Abstract: The invention includes a process for producing a reaction bonded silicon carbide composite reinforced with coated silicon carbide fibers which is suitable for high temperature applications. The process includes the steps of coating SiC fibers with AlN, BN or TiB.sub.2 ; treating the coated fibers with a mixture of SiC powder, water and a surfactant; preparing a slurry comprising SiC powder and water; infiltrating the coated fibers with the slurry to form a cast; drying the cast to form a green body; and reaction bonding the green body to form a dense SiC fiber reinforced reaction bonded matrix composite.The invention further includes a SiC fiber reinforced SiC composite comprising a reaction bonded SiC matrix, a SiC fiber reinforcement possessing thermal stability at high temperatures and an interface coating on the fibers having chemical and mechanical compatibility with the SiC matrix and with the SiC fibers.Type: GrantFiled: May 22, 1995Date of Patent: July 1, 1997Assignee: The Carborundum CompanyInventors: Stephen Chwastiak, Sai-Kwing Lau, Carl H. McMurtry, Gajawalli V. Srinivasan
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Patent number: 5635430Abstract: Silicon carbide sintered bodies having controlled porosity in the range of about 2 to 12 vol %. in which the pores are generally spherical and about 50 to 500 microns in diameter, are prepared from raw batches containing a polymer fugitive. Sintered bodies in the form of mechanical seal members exhibit lower power consumption at low PV and, in addition, lower wear rates at high PV in comparison to commercially available silicon carbide seal members.Type: GrantFiled: June 1, 1995Date of Patent: June 3, 1997Assignee: The Carborundum CompanyInventors: Ramesh Divakar, Sai-Kwing Lau, Stephen Chwastiak
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Patent number: 5296311Abstract: The invention provides silicon carbide fiber-reinforced, reaction-bonded silicon carbide composites suitable for high temperature applications in which the silicon carbide fiber is coated with AlN, BN or TiB.sub.2. The composites offer superior fracture toughness which is ascribed to fiber pullout. The invention also includes a process for making the composites.Type: GrantFiled: March 17, 1992Date of Patent: March 22, 1994Assignee: The Carborundum CompanyInventors: Carl H. McMurtry, Sa-Kwing Lau, Gajawalli V. Srinivasan, Stephen Chwastiak
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Patent number: 5202105Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.Type: GrantFiled: July 5, 1990Date of Patent: April 13, 1993Assignee: Stemcor CorporationInventors: Wolfgang D. G. Boecker, Stephen Chwastiak, Tadeusz M. Korzekwa, Sai-Kwing Lau
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Patent number: 5002905Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.Type: GrantFiled: April 22, 1988Date of Patent: March 26, 1991Assignee: Stemcor CorporationInventors: Wolfgang D. G. Boecker, Stephen Chwastiak, Tadeusz M. Korzekwa, Sai-Kwing Lau
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Patent number: 4981665Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.Type: GrantFiled: April 22, 1988Date of Patent: January 1, 1991Assignee: Stemcor CorporationInventors: Wolfgang D. G. Boecker, Stephen Chwastiak, Tadeusz M. Korzekwa, Sai-Kwing Lau
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Patent number: 4756895Abstract: Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100.degree. C. to 2500.degree. C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.Type: GrantFiled: August 22, 1986Date of Patent: July 12, 1988Assignee: Stemcor CorporationInventors: Wolfgang D. G. Boecker, Stephen Chwastiak, Tadeusz M. Korzekwa, Sai-Kwing Lau
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Patent number: 4209500Abstract: A low molecular weight, anisotropic pitch consisting of essentially 100 percent mesophase and suitable for spinning into continuous filaments can be prepared by passing an inert gas through an isotropic carbonaceous pitch at a rate of at least 4.0 scfh. per pound of pitch while heating the pitch at a temperature of from about 380.degree. C. to about 430.degree. C. to produce mesophase and simultaneously agitating the pitch so as to produce a homogeneous emulsion of the mesophase produced and the remaining non-mesophase portion of the pitch, said heating and agitation being continued until the pitch has been essentially completely converted to mesophase and the emulsion has been transformed into an essentially single phase system. When examined under polarized light, the pitches of the present invention are seen to consist of a single phase which is essentially completely anisotropic.Type: GrantFiled: October 3, 1977Date of Patent: June 24, 1980Assignee: Union Carbide CorporationInventor: Stephen Chwastiak