General Electric Company

Cts Corporation

The United States of America As Represented by the United States

Wayne D Pasco

Frederic Joseph Klug

Ronald H Arendt

Richard J Charles

Stephan P Mitoff

Charles D Greskovich

Marcus P Borom

Svante Prochazka

Paul Steven Svec

Stephen L Dole

Raymond G Blair

Randel N Simons

Edward J Rombach

Michael Francis Xavier Gigliotti

Michael A Newell

David R Heine

Glenn W Ledder

A method of forming metallization patterns on a block of dielectric material wherein the entire surface area of the dielectric block is encased with a conductive material and unwanted conductive metal is ablatively etched from a designated surface area of the dielectric block to form desired metallized circuit patterns.

Ablative method for forming RF ceramic block filters

A ceramic casting shell mold having a pre-selected shape comprises alternate, repeating layers of a ceramic coating material and a ceramic stucco, defining a total thickness of the shell mold; and a ceramic-based reinforcing sheet disposed in the alternate, repeating layers of coating material and stucco at an intermediate thickness. The ceramic-based reinforcing sheet comprises a one-piece monolithic, integral body, which comprises a pattern of holes that enhance bonding between the ceramic-based reinforcing sheet and adjacent ones of the alternate, repeating layers of ceramic coating material. The ceramic-based reinforcing sheet conforms to the shape of the mold and providing structural reinforcement to the mold.

Reinforced ceramic shell molds, and related processes

Ablative RF ceramic block filters

A ceramic filter with recessed shield 200 is provided. Filter 200 contains a filter body with a block of dielectric material having a top surface 202, a bottom surface 204, and side surfaces 206, 208, 210 and 212 respectively. Filter 200 also has a plurality of metallized through-holes 214 extending from the top surface 202 to the bottom surface 204 defining resonators. Each of the resonators has a corresponding plurality of embedded receptacles 220, which contain an unmetallized area therein, adjacent to the plurality of metallized through-holes 214, providing a ring of isolation 222. A recessed channel 224 extends perpendicularly across each of the plurality of embedded receptacles 220 and has a groove 226 therein which is complementarily configured to receive a metallic shield 228. The metallic shield 228 is disposed in the recessed channel 224 and is connected to the metallization layer of the plurality of embedded receptacles 220. The metallic shield 228 is attached to the dielectric block with a design that reduces the size and volume of the filter 200.

Ceramic filter with recessed shield

An aluminum nitride ceramic body with a thermal conductivity of at least 0.5 W/cm.K at 25.degree. C. is produced by shaping a particulate mixture of aluminum nitride powder and an additive selected from the group consisting of CaF.sub.2, SrF.sub.2, BaF.sub.2 and mixtures thereof into a compact and liquid phase sintering the compact.

Alkaline earth fluoride additive for sintering aluminum nitride

A process for producing an hermetic feedthrough in a ceramic substrate by providing a sheet of liquid phase sinterable ceramic composition having a feedthrough hole, filling the feedthrough hole with refractory metal metallization material, firing the resulting structure to produce a sintered substrate and adherent metallization wherein the metallization is comprised of continuous phases of refractory metal and glass, contacting the refractory metal with electrically conductive intrusion metal and heating the resulting structure to a temperature at which the glassy phase is fluid, the refractory metal is solid, and the intrusion metal is liquid whereby the liquid metal preferentially wets the refractory metal, migrates into the metallization displacing glass and, upon subsequent solidification, partially or wholly occupies the volume space originally containing the continuous glass phase.

Hermetic feedthrough in ceramic substrate

An aluminum nitride ceramic body with a thermal conductivity of at least 0.5 W/cm.multidot.K at 25.degree. C. is produced by shaping a particulate mixture of aluminum nitride powder and an additive selected from the group consisting of YF.sub.3, ScF.sub.3, LF.sub.3 where L is La, Ce, Pr, Nd, Sm, Gd, Dy, Ho and Er and a mixture thereof into a compact and liquid phase sintering the compact.

Rare earth fluoride additive for sintering aluminum nitride

Method of making hermetic feedthrough in ceramic substrate

A process for increasing electrical conductance of a metallization on a ceramic substrate wherein the metallization is an intermixture of continuous phases of refractory metal and glass which comprises contacting the refractory metal with an electrically conductive intrusion metal and heating the resulting structure to a temperature at which the glassy phase is fluid, the refractory metal is solid, and the intrusion metal is liquid whereby the liquid metal preferentially wets the refractory metal, migrates into the metallization displacing glass and, upon subsequent solidification, partially or wholly occupies the volume space originally containing the continuous glass phase.

Secondary metallization by glass displacement in ceramic substrate

A cofired structure comprised of a refractory metal metallization supported by a substrate free of large voids is produced by forming a liquid phase sinterable ceramic composition containing SiO.sub.2 in some form and a sulfate of an alkali metal and/or an alkaline earth metal, admixing the composition with an organic binding medium, shaping the mixture into a thin sheet, contacting the sheet with refractory metal metallization material, and cofiring the resulting structure whereby the free carbon produced by pyrolysis of the organic medium is removed by reaction with the sulfate before closed porosity is initiated.

Process for cofiring structure comprised of ceramic substrate and

A process of making a porous carbonate-containing structure for use in a molten carbonate fuel cell, wherein a suitable porous structure is prepared having disposed therein a metal salt selected from the alkali metals and the alkaline earth metals or mixtures thereof with at least a portion of the salt being a monobasic organic acid salt. The monobasic acid salt is converted to the carbonate in situ by heating in the presence of oxygen. Both electrode and electrolyte structures can be prepared. Formic acid is preferred.

Process for making structure for a MCFC

A particulate mixture of an alkali metal carbonate solvent, titanium oxide, and an alkaline earth reactant selected from the group consisting of barium oxide, strontium oxide, and mixtures thereof, is heated to melt the alkali metal carbonate solvent in which the reactants dissolve and react precipitating a titanate selected from the group consisting of barium titanate, strontium titanate and mixtures thereof.

Molten salt synthesis of barium and/or strontium titanate powder

An alumina investment casting mold has a microstructure characterized by the porous nature of the interconnecting alumina grains which is indicative of alumina-silica molds fired in a reducing atmosphere to remove the silica.

Alumina shell molds used for investment casting in directional

A method of firing alumina-based ceramic core compacts includes firing the compact in a controlled atmosphere in a closed retort whereby at least a portion of the gas of the controlled atmosphere is caused to flow down, around and through the porous compact by aspiration.

Method for firing low density graphite/alumina compacts and cores

A reactant fugitive filler material is employed in a material composition which includes alumina-based ceramics of one or more particle sizes. The reactant fugitive material provides sufficient reactant material at an elevated temperature to form a fired ceramic article which has a porous microstructure in which the grain morphology is characteristic of grains which have undergone vapor phase transport action.

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Ballston Lake, NY, United States of America

Wayne D Pasco