Gte Laboratories Incorporated

F Joseph Reid

Han J Kim

William H Rhodes

J Thomas Smith

Carr L Quackenbush

Frederick J Scimeca

Polycrystalline ceramic bodies of Si.sub.3 N.sub.4 when prepared to obtain an intergranular phase which is substantially crystalline, exhibits significantly improved mechanical strength at elevated temperatures above 1,000.degree. C. up to 1600.degree. C. over bodies having glass-containing intergranular phases.

S13N4 Having high temperature strength and method

An article of manufacture comprising a substantially transparent high density polycrystalline yttria-based body consisting essentially of yttria and from 0.1 to 5 wt. % MgO or from 0.1 to 5 wt. % MgAl.sub.2 O.sub.4. Transparent yttria-based bodies according to this invention are particularly useful as envelopes for high pressure sodium vapor lamps.

Transparent yttria ceramics containing magnesia or magnesium aluminate

An article of manufacture is provided comprising a substantially transparent high density polycrystalline yttria-base body consisting essentially of yttria and from about 0.01 to 5 wt. % alumina. A method for preparing the transparent yttria doped with alumina is also provided comprising admixing alumina or a precursor thereof with yttria or a precursor thereof, drying the admixed powders, calcining the admixed powders and pressing the calcined powders into a desired shape and thereafter sintering the shaped powder for about 1/4 to six hours at a temperature above the eutectic temperature at a sufficiently low oxygen atmosphere to prevent oxidative contaminants.

Transparent yttria ceramics and method for producing same

An article of manufacture is provided comprising a substantially transparent high density polycrystalline yttria-base body consisting essentially of yttria and from about 0.01 to 5 wt. % alumina. A method for preparing the transparent yttria doped with alumina is also provided comprising admixing alumina or a precursor thereof with yttria or a precursor thereof, drying the admixed powders, calcining the admixed powders and pressing the calcined powders into a desired shape and thereafter sintering the shaped powder for about 1/4 to 6 hours at a temperature above the eutectic temperature at a sufficiently low oxygen atmosphere to prevent oxidative contaminants.

This application describes the step-wise application of heat during the sintering of a mixture of silver and cadmium oxide to give an alloy having improved characteristics. These alloys are useful as electric contacts in high electric current applications.

Process for preparing silver-cadmium oxide alloys

This application describes a method of preparing cadmium-containing refractory metal-silver alloys by using a liquid phase sintering technique featuring a cadmium vapor over-pressure. The resultant alloys are useful as electric contacts in high electric current applications.

Process for preparing refractory metal-silver-cadmium alloys

This application describes the addition of an alkali metal, generally in the form of a salt thereof, to a mixture of silver and cadmium oxide, prior to the sintering step, to improve the as-sintered densities of the resultant alloy material.

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Acton, MA, United States of America

F Joseph Reid