Westinghouse Electric Corporation

Northrop Grumman Systems Corporation

Electric Power Research Institute Incorporated

Other

US Government As Represented by the Secretary of the Army

Norhtrop Grumman Corporation

Northrop Grumman Cropration

Kenneth C Radford

Deborah P Partlow

Stephen R Gurkovich

Andrew J Piloto

Andrew S Sweetana, Jr

Robert G Johnson

Karl F Schoch, Jr

Alex E Bailey

Theodore R Vasilow

Lyon Mandelcorn

Beryl H Parks

William G Clark, Jr

Geoffrey Barlow

Robert L Miller

William G Carlson

Ian L Wilson

James M Pope

James F Roach

Jeffrey Charles Bowker

Don E Harrison

Robert R Fuller

Larry R Eisenstatt

Peter J Kuchirka

Shih-Ming Ho

Philip A Panackal

Bruce M Argall

William C Carlson

Paul P Frank

Nicholas Papadakis

Jay E Lane

John Bowers

Jay Edgar Lane

Eileen M Wojtal

Eugene R Danielson

Herbert W Keller

Thermal interface materials are essential for proper operation of electronic assemblies. They are used between surface mount components and printed wiring boards and between printed wiring boards and metal heat sinks. Their function is to bond the components together and allow good heat transfer between the parts being bonded. The approach disclosed in this invention is a fully-cured, flexible, filled elastomer that is coated on both sides with a partially cured, filled adhesive, which can be conveniently made by a low cost tape casting process. This unique approach offers a combination of good adhesion to both bonding surfaces, good heat transfer, compliance to accommodate mismatched coefficient of thermal expansion, rework capability, control of flow of the adhesive during cure, and easy handling of uncured material.

Thermal interface material for electronic assemblies

There is disclosed herein a high voltage and high temperature power electronics capacitor which comprises one or more insulator layers of mica paper, and one or more metal conductor layers, all dispersed in a pressurized environment of a nonreactive and high voltage strength gas maintained at near ambient to about 405.2 kPa of pressure. The insulator and conductor layers are isolated and separated from one another by the alternating placement of conductor layers between said insulator layers. These capacitors are readily packaged for commercial use in containers or housings of almost any geometric form and any material of construction. Moreover, low inductance ceramic bushings can be employed on these containers for establishing external electrical contacts. These capacitors can be economically manufactured and used in large commercial volumes with currently available materials and production methods.

Method of making a power electronics capacitor

A capacitor module having a solid dielectric is cleared in a gaseous environment having an electric strength greater than that of air at a pressure of one atmosphere. A plurality of such cleared capacitor modules is formed into a stack which itself is then cleared by the same clearing process. During intended operation in an electric circuit, the capacitor arrangement would be maintained in such gaseous environment having an electric strength greater than that of air at a pressure of one atmosphere.

Capacitor arrangement and method of stabilizing same

An oxide ceramic composite suitable for fabricating components of combustion turbines and similar high temperature environments. The composite is fabricated by dispersing metal particles in a fiber preform and infiltrating the fiber preform with sol-gel matrix precursor material. Alternatively, the metal particles are mixed into the sol-gel matrix precursor material and the preform is infiltrated with the mixture. Later in the fabrication process, the metal particles oxidize and become oxidized metal when the sol-gel matrix precursor material is sintered. The oxidized metal has more volume and mass than the metal particles. As a result, the oxidized metal contributes to increasing the density of the composite so that it is suitable for use in combustion turbines and similar high temperature environments.

Process of making oxide ceramic composites

Materials and methods for the fabrication of high density, low temperature fired microwave ferrites for use in microwave power devices, transmission line elements, isolators, circulators, and phase shifters. Very fine (sub-micron) ferrite powders made by sol-gel methods are mixed with solvents and binders then tape-cast. Ferrite tapes in the unfired state are cut into complex shapes and may be provided with via holes. These ferrite sheets are fired discretely, or are laminated, cofired with printed metal pastes, or other active and passive ceramic tapes.

Process for fabricating a microwave power device

We disclose a fabrication method for integrating passive devices such as capacitors, resistors and circulators into ceramic packages for electronic systems. The method utilizes a glass or glass/ceramic as a bonding agent which is incorporated as one of the layers in the multilayer package. The integration of such passive devices eliminates the tedious mounting of these devices on the package, permitting a smaller, more reliable, less expensive and lighter weight product. This method allows the integration of passive devices having firing temperatures far different from that of the ceramic package itself, permitting combinations of materials that cannot be densified, or cofired together.

Post-firing method for integrating passive devices into ceramic

The invention provides for an electronic package having a buried passive component such as a capacitor therein, and a method for fabricating the same. The electronic package preferably includes a passive component portion which includes a plurality of layers of high K dielectric material, a signal processing portion which includes a plurality of layers of low K dielectric material, and at least one buffer layer interposed between the passive component portion and the signal processing portion. Metallization is preferably printed upon at least one of the layers of high K dielectric material and at least one of the layers of low K dielectric material. Preferably, the layers are co-fired at a temperature below approximately 1200.degree. C. to form the electronic package and each of the buffer layers contains approximately 25 to 100% barium compound. Via conductors may also be provided through the buffer layers to electrically couple the passive component portion and the signal processing portion and the metallization and the via conductors may be selected from highly conductive materials such as gold, silver, copper and alloys thereof.

Electronic package having buried passive components

A method for forming a low temperature cofired ceramic package which is made using a multi-layered densified spherical powder formed via a sol-gel process. This densified powder is formed from layers of SiO.sub.2 reacted with trimethyl borate. The spherical powder has a preselected particle size and boron content sufficient to render the low temperature cofired ceramic package fully dense, even in the presence of a second phase filler ceramic, at a sintering temperature below 1000.degree. C. Binder material is added to the spherical powder and ceramic filler to form a plurality of tapes. A ceramic assembly is then formed by layering the plurality of tapes upon one another and firing the ceramic assembly at a temperature below 1025.degree. C. to form a fully dense cofired ceramic package. In order to form the multi-layered densified spherical powder, a silica core, which is formed using a sol-gel process, is reacted with trimethyl borate. An additional layer of silica is provided upon the reacted product which, in turn, is reacted with trimethyl borate. This process is continued until a spherical powder of desired size is formed.

Method for manufacturing a low loss, low temperature cofired ceramic

A ceramic capacitor suitable for high energy density and high temperature application is disclosed. Such a capacitor is prepared by producing the selected ceramic powder via the sol-gel process forming the capacitor to the desired shape with the resulting powder using tape casting technology and firing the 'green' form so produced.

High power capacitor

A dual mode radar transparency allowing passage of both RF radiation and IR radiation comprises an aerogel base and ceramic skin overlaying the aerogel base. The aerogel base comprises a low density ceramic material. A method of fabricating a dual mode radar transparency allowing passage of both RF radiation and IR radiation comprises the steps of preparing a colloidal dispersion of a ceramic material in a medium, increasing a concentration of the colloidal dispersion by evaporation to create a suspension, and placing the suspension in a mold. The suspension is solidified to form an aerogel and the aerogel is joined to a ceramic skin.

Dual mode radar transparency and method of fabricating same

A multi-layer capacitor comprising a stack of sheet electrodes with an insulating dielectric layer sandwiched between these layers is disclosed. The dielectric layer formed on the electrode is prepared by the 'sol-gel' process.

High capacitance thin film capacitor

A battery, having a plurality of cells stacked in series. Each of the cells having a positive electrode, a negative electrode and a separator that contain an electrolyte. The battery utilizes a thin section of carbon provided between adjacent cells as the bipolar walls. The bipolar wall may be a thin, preferably flexible, sheet of graphite. The carbon bipolar wall may also be formed by tape casting.

Carbon bipolar walls for batteries and method for producing same

A vanadium oxide compound having the formula VO.sub.2 is disclosed for the purpose of selectively shielding an electromagnetic transmitter or receiver. Vanadium oxide exhibits a marked and rapid transition from dielectric and transparent to electromagnetic radiation to metallic and impervious to such radiation at a specific temperature, 68.degree. C. The compound is preferably mounted as a thin layer on a substrate which has been specifically selected for the desired application. The transmission of radiation is then temperature selected. The preferred method of deposition is an organic hydrolysis reaction.

Method of preparing a switchable shield

Optical and electromagnetic field

A method of manufacturing a varistor utilizes preselected amounts of ZnO which are combined with specified amounts of additives including B, Na, Bi.sub.2 O.sub.3 and BaO to form a variety of compositions. Each composition is pressed into a disc. The disc is then sintered at a first selected temperature. Afterwards, the disc is annealed at a second selected temperature. The specific compositions disclosed render a varistor with improved high temperature performance when the annealing step is followed with a low temperature tempering cycle at approximately 250.degree. C.

Surge stability improvement of zinc oxide varistor discs

Growing community of inventors

North Huntingdon, PA, United States of America

Kenneth C Radford