Gte Products Corporation

Gte Sylvania Incorporated

Geoffrey L Harris

Edward R Kimmel

Clarence D Vanderpool

Joseph E Ritsko

Howard L Acla

Mary E Shaffer

William Scheithauer, Jr

James Q Steigelman

Thomas R Pinkowski

David R Moyle

Robert F Northrop

Roger B Bargainnier

Glenn A Shaffer, Deceased

By Irene Charland, Administrator Dbn Cta

Christopher A Kronenwetter

A method is disclosed for producing tungsten carbide and a cemented tungsten carbide article therefrom which consists essentially of forming a uniform mixture of tungsten metal powder and carbon wherein the tungsten metal powder has an aveage particle size of from about 1 to about 4 micrometers in diameter, wherein the surface area of the carbon is no greater than about 12 m.sup.2 /g, and wherein the amount of the carbon is sufficient to react with essentially all of the tungsten to produce tungsten carbide in the subsequent heating step, heating the mixture in a non-oxidizing atmosphere at a temperature of at least about 1200.degree. C. for a sufficient time to produce tungsten carbide wherein the amount of free carbon is less than about 0.05% by weight and wherein the tungsten carbide has an average particle size of from about 1 to about 4 micrometers in diameter, forming a uniform second mixture of the tungsten carbide powder, a wax binder, and cobalt powder wherein the cobalt content of the second mixture is from about 3% to about 20% by weight of the second mixture, forming a green article from the second mixture, and sintering the green article at a temperature of from about 1400.degree. C. to about 1300.degree. C. to produce the cemented tungsten carbide article wherein the microstructure of the cemented tungsten carbide article exhibits an average of no more than 1 grain having a particle size of greater than about 7 micrometers in diameter per about 0.15 cm.sup.2 of surface of the article.

Method for producing tungsten carbide and cemented tungsten carbide

Tungsten carbide is produced by mixing tungsten oxide or ammonium paratungstate with carbon to form a mixture which is substantially reduced in a non-reducing atmosphere in the presence of sufficient carbon to produce a carbon content in the resulting mixture of less than seven percent by weight, and adding sufficient carbon to the resulting reduced mixture to increase the carbon content to at least the stoichiometric amount needed to form monotungsten carbide prior to carburization of the mixture to monotungsten carbide.

Method of producing monotungsten carbide powder

A uniform, large size tungsten powder having properties which make it suitable for producing large size tungsten carbide powder is produced by doping a tungsten oxide starting powder with a lithium compound prior to reduction

Method of producing tungsten and tungsten carbide powder

A flexible sheet of a top layer of nickel brazing alloy particles overcast on a tapecast base layer of tungsten carbide particles, the brazing alloy particles and carbide particles each dispersed in and supported by an organic binder matrix, when placed on a substrate dewaxed and heated to about 1100.degree. C., forms a braze infiltrated hardfacing coating of tungsten carbide particles in a braze alloy matrix, which coating is metallurgically bonded to and enhances the hardness and wear resistance of the coated substrate.

Flexible bilayered sheet, one layer of which contains abrasive particles

Extra fine cobalt metal powder (up to about 0.8 microns) having less than 100 parts per million cation impurities is produced by a process in which cobalt pentammine chloride is digested in a dilute ammonium hydroxide solution to form a black precipitate, which is separated and heated in a hydrogen atmosphere to reduce the precipitate directly to cobalt metal powder. The cobalt pentammine chloride may be obtained by digesting a cobalt source in hydrochloric acid, adding ammonium hydroxide, oxidizing the cobaltous ion to cobaltic ion, and reducing the pH with hydrochloric acid to less than 1.0 in order to precipitate cobalt pentammine chloride. The final cobalt metal powder is useful, for example, as a starting material in the manufacture of cemented carbides.

Method for producing extra fine cobalt metal powder

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Monroeton, PA, United States of America

Geoffrey L Harris