Aluminum Company of America

Westinghouse Electric Corporation

Electric Power Research Institute Incorporated

United States of America As Represented by the Secretary of the Air Force

Other

The United States of America As Represented by the United States

Tapan K Gupta

Jau-Ho Jean

William G Carlson

Andrew S Sweetana, Jr

William D Straub

William N Lawless

Donald D Blewitt

George J Bich

Shih M Ho

Joseph C Osterhout

Richard E Kothmann

Douglas M Mattox

Herbert E Pietsch

Gerald B Boyette

Philip L Hower

A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 5.0 and a TCE of 2.0-4.0 ppm/c. The composition is formed from a mixture comprising 25-50 weight percent of a low temperature glass selected from the group consisting of borosilicate glass, zinc borate glass and combinations thereof, 50-75 weight percent of a high temperature glass selected from the group consisting of high silica glass, titanium silicate glass and combinations thereof, and 1-10 weight percent of ceramic material having a particle size of less than about 3 microns. The mixture can be combined with a polymeric binder to produce an unfired green tape which is co-fireable with high conductivity metallurgies such as gold, silver and silver/palladium. A preferred ceramic material is colloidal alumina.

Suppression of crystal growth in low dielectric inorganic composition

A ceramic composition for forming ceramic dielectric body having a dielectric constant of less than about 5.5 and a TCE of less than about 5.0 ppm/.degree.C. The composition comprises a mixture of finely divided particles of 10-90 vol. % borosilicate glass and 10-90 vol. % of a material selected from the group consisting of Ga.sub.2 O.sub.3, Ga.sub.2 SiO.sub.5, Ga.sub.2 TiO.sub.5, GaAs, GaPO.sub.4 and any gallium-contained compounds to inhibit the formation of crystalline forms of silica. The composition can be used with a polymeric binder to produce an unfired green tape which is co-fireable with high conductivity metallurgies such as gold, silver and silver/palladium.

Devitrification inhibitor in low dielectric borosilicate glass

A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 5.5 and a TCE of less than about 3.5 ppm/.degree.C. The composition comprises a mixture of finely divided particles of 20-80 vol. % borosilicate glass and 20-80 vol. % of Al.sub.x B.sub.y O.sub.z wherein x is in the range of 4 to 22, y is in the range of 2 to 5, and z is in the range of 9 to 36. The Al.sub.x B.sub.y O.sub.z inhibits the formation of crystalline forms of silica. The composition can be used with a polymeric binder to produce an unfired green tape which is co-fireable with high conductivity metallurgies such as gold, silver and silver/palladium.

Aluminum borate devitrification inhibitor in low dielectric borosilicate

A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 4.2. The composition comprises a mixture of finely divided particles of 25-50 vol. % borosilicate glass and 50-75 vol. % high silica glass. The composition can be used with a polymeric binder to produce an unfired green tape which is co-fireable with high conductivity metallurgies such as gold, silver and silver/palladium.

Low dielectric inorganic composition for multilayer ceramic package

A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 4.2 and a TCE of less than about 4.0 ppm/c. The composition comprises a mixture of finely divided particles of 25-50 vol. % borosilicate glass and 50-75 vol. % high silica glass and sufficient amounts of crystalline ceramic material to inhibit the formation of crystalline forms of silica. The composition can be used with a polymeric binder to produce an unfired green tape which is co-fireable with high conductivity metallurgies such as gold, silver and silver/palladium.

Crystal growth inhibitor for glassy low dielectric inorganic composition

The composite insulation coating consists of a mixture of glass and ceramic oxide(s), coated onto a wire by conventional wire enameling techniques followed by heat treatment at 600.degree.-850.degree. C. The enamel when initially applied, the 'green' coat slurry, consists of four components: (1) the glass, (2) an inorganic filler (ceramic oxide powder, (3) an organic binder and (4) an organic solvent. The glasses can be selected from several commercial glasses (Corning 7570 and 7050) as well as Westinghouse glasses A-508, M 3072 and M 3073. None of these glasses contain lead or boron, allowing for nuclear applications. Suitable ceramic fillers are alumina, and the CeramPhysics, Inc. ceramics SC1C and SC1A. Organic binder materials and solvents are used. It is preferable that a copper wire to be coated with Ni, Inconel or Cr prior to coating with the subject insulation. For superconductors, the brittle nature of Nb.sub.3 Sn wire and the high reaction temperature (.about.700.degree. C.) required to form it preclude the use of standard organic insulation systems. The inorganic insulation with SC1C and SC1A ceramics, characterized by unusually high specific heats and thermal conductivities at cryogenic temperatures, offers the opportunity of providing increased enthalpy stabilization in a superconducting winding. The glass and ceramic is chosen so that the vitrification temperature of the composite coincides with the reaction temperature of 600.degree.-800 .degree. C. The most successful glasses meeting this criterion are A-508 and M3072.

Method of coating superconductors with inorganic insulation

A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 5.5 and a TCE of less than about 4.5 ppm/.degree. C. The composition comprises a mixture of finely divided particles of 25-50 vol. % borosilicate glass 40-75 vol. % silica glass and 1-40 wt. % of a material selected from the group consisting of Ga.sub.2 O.sub.3, Ga.sub.2 SiO.sub.5, Ga.sub.2 TiO.sub.5, GaAs, GaPO.sub.4 and any gallium-contained compounds to inhibit the formation of crystalline forms of silica. The composition can be used with a polymeric binder to produce an unfired green tape which is co-fireable with high conductivity metallurgies such as gold, silver and silver/palladium.

Gallium-containing glassy low dielectric ceramic compositions

The need for high current, high field, low loss, stable superconductors has led to the development of multifilamentary Nb.sub.3 Sn as the most promising candidate for use in superconducting machines. However, the brittle nature of Nb.sub.3 Sn and the high reaction temperature (.about.700.degree. C.) required to form it preclude the use of standard organic insulation systems. A recently developed class of high temperature dielectric materials which are characterized by unusually large specific heats and thermal conductivities at cryogenic temperatures offers the opportunity of providing increased enthalpy stabilization in a superconducting winding, as well as the required dielectric strength. The inorganic insulation system consists of a composite glass and ceramic powder vitrified at a temperature which coincides with the superconducting formation temperature of 600.degree.-800.degree. C. The glass and the ceramic is chosen in such a way that the vitrification temperature of the composite coincides with the reaction temperature of 600.degree.-800.degree. C. The most successful glasses meeting this criterion are two Westinghouse glasses designated A-508 and M3072. Suitable ceramic fillers are Al.sub.2 O.sub.3 and the Ceram Physics, Inc. ceramics SClC and SClA. Organic binders and solvents are used. Cladding with, e.g., nickel is preferable for the copper layer of Nb.sub.3 Sn wire.

Inorganic wire insulation for super-conducting wire

A glass-ceramic composition for forming a glass-ceramic dielectric body having a dielectric constant of less than about 4.5, a firing temperature of less than about 950.degree. C. and a sintered density of greater than 95% theoretical density. The composition is formed from a mixture consisting essentially of finely divided particles of 40-50 vol. % borosilicate glass and 50-60 vol. % cordierite. The borosilicate glass comprises approximately 20-35 wt. % B.sub.2 O.sub.3 and approximately 60-75 wt. % SiO.sub.2. The exact particle size ratio of the cordierite to borosilicate glass that is used will depend on the proportions of the components, the desired fired density and the firing temperature. The mixture is fired at a temperature of less than 1000.degree. C.

Dielectric composition containing cordierite and glass

A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 4.5 and a TCE of less than about 4.0 ppm/c. The composition comprises a mixture of 20-50 wt. % borosilicate glass 40-75 wt. % of a glass selected from the group consisting of glass containing 95-98 wt. % silica, titanium silicate glass and combinations thereof and sufficient amounts of gallium to inhibit the formation of crystalline forms of silica. The composition can be combined with a polymeric binder to produce an unfired green tape which is co-fireable with high conductivity metallurgies such as gold, silver and silver/palladium.

Gallium crystal growth inhibitor for glassy low dielectric inorganic

A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 4.2 at 1 MHz and a linear thermal expansion coefficient of 2.5-3.0 ppm/.degree.C. from room temperature to 200.degree. C. The composition comprises a mixture of finely divided particles of 20-50 wt. % borosilicate glass, 40-75 wt. % titanium silicate glass and sufficient amounts of crystalline ceramic material to inhibit the formation of crystalline forms of silica. The composition can be used with a polymeric binder to produce an unfired green tape which is co-fireable with high conductivity metallurgies such as gold, silver and silver/palladium.

A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 4.2 at 1 MHz and a linear thermal expansion coefficient of 2.5-3.0 ppm/.degree. C. from room temperature to 200.degree. C. The composition comprises a mixture of finely divided particles of 25-50 vol. % borosilicate glass and 50-75 vol. % titanium silicate glass. The composition can be used with a polymeric binder to produce an unfired green tape which is co-fireable with high conductivity metallurgies such as gold, silver and silver/palladium.

A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 4.2 and a TCE of less than about 4.0 ppm/c. The composition comprises a mixture of finely divided particles of 25-50 weight percent borosilicate glass and 50-75 weight percent high silica glass and 1-25 weight percent sufficient of crystalline ceramic material to inhibit the formation of crystalline forms of silica. The high silica glass contains essentially 0.5-1 wt. % alumina, 1-5 wt. % B.sub.2 O and approximately 95-98 wt. % SiO.sub.2. The mixture is fired at a temperature of less than 1000.degree. C.

A ceramic composition for forming a ceramic dielectric body having a dielectric constant of less than about 4.2. The composition is formed from a mixture of finely divided particles of 25-50 vol. % borosilicate glass and 50-75 vol. % high silica glass. The borosilicate glass comprises approximately 20-35 wt. % B.sub.2 O.sub.3 and approximately 60-80 wt. % SiO.sub.2. The high silica glass contains essentially 0.5-1 wt. % alumina, 1-5 wt. % B.sub.2 O.sub.3 and approximately 95-98 wt. % SiO.sub.2. The composition can be fired at a temperature of less than 1000.degree. C.

A nonlinear resistor which exhibits substantial temperature independence over a wide range of temperatures, including low temperatures, is provided. The resistor is formed of a zinc oxide-based ceramic composition which exhibits nonlinear voltage/current characteristics and is essentially unafffected by magnetic fields. The nonlinear resistor provides protection for electrical devices in a circuit from voltage surges and/or transients. In a preferred form, the resistor is manufactured as a multilayer capacitor-type device.

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Monroeville, PA, United States of America

Tapan K Gupta