Osram Sylvania Inc.

Gte Products Corporation

Other

David L Houck

Michael J Scheithauer

Leonid P Dorfman

Nelson E Kopatz

Sanjay Sampath

Muktesh Paliwal

Vidhu Anand

Thomas A Wolfe

Raj P Singh

David J Port

Joseph E Ritsko

Michael R Pierce

Jeffrey N Dann

Frank J Venskytis

Scott A Braymiller

Anna T Spitsberg

Gail T Meyers

Richard F Cheney

James R Spencer

Howard L Acla

Jack E Vanderpool

Raj Pal Singh Gaur

Jen S Lee

Dennis C Smouse

Clarke D Davis

Frank D Kinney

James O Steigelman

A novel molybdenum compound, ammonium dodecamolybdomolybdate (AMM), is described which may be used in the manufacture of molybdenum metal and molybdenum carbide powders. The molybdenum compound is a dodecaheteropoly acid salt having a Keggin-type structure wherein molybdenum resides in both the hetero as well as peripheral atomic positions. The novel compound has the general formula (NH)MoMoO&#xb7;6HO. Because of its low solubility, the compound can be crystallized efficiently and at a high purity from ammonium molybdate solutions.

Ammonium dodecamolybdomolybdate and method of making

A Mo&#x2014;Cu composite powder is provided which is comprised of individual finite particles each having a copper phase and a molybdenum phase wherein the molybdenum phase substantially encapsulates the copper phase. The composite powder may be consolidated by conventional P/M techniques and sintered without copper bleedout according to the method described herein to produce Mo&#x2014;Cu pseudoalloy articles having very good shape retention, a high sintered density, and a fine microstructure.

Mo-Cu composite powder

Mo-Cu Composite powder

An electrochemical displacement-deposition method for making composite metal powders is described. The method is carried out by combining tungsten or molybdenum metal particles with particles of silver oxide or copper oxide in an aqueous hydroxide solution. Heat is applied to the solution to cause the oxide particles to convert to silver or copper metal particles which are substantially adhered to the refractory metal particles. Unlike conventional methods, it is not necessary to heat the oxide powders to a very high temperature in a reducing atmosphere in order to form the composite metal powder.

Electrochemical displacement-deposition method for making composite metal powders

A novel molybdenum compound, ammonium dodecamolybdomolybdate (AMM), is described which may be used in the manufacture of molybdenum metal and molybdenum carbide powders. The molybdenum compound is a dodecaheteropoly acid salt having a Keggin-type structure wherein molybdenum resides in both the hetero as well as peripheral atomic positions. The novel compound has the general formula (NH ) Mo MoO .6H O. Because of its low solubility, the compound can be crystallized efficiently and at a high purity from ammonium molybdate solutions.

A method for spheridizing silicon metal particles is described. The method involves injecting irregular silicon metal particles into a high-temperature plasma reactor to melt at least 50 weight percent of the particles. The molten droplets are solidified to form substantially spherical silicon particles having a thin SiO coating which may be removed by treating with a weak hydroxide solution.

Method of spheridizing silicon metal powders

A W&mdash;Cu&mdash;Ni alloy having thermophysical properties suitable for use in electrical contacts and electrodes is described. The alloy is formed by direct sintering of a powder blend comprising a tungsten-copper composite powder and a nickel powder. The tungsten-copper composite powder component of the blend comprises individual dual phase particles having a copper phase and a tungsten phase wherein the tungsten phase substantially encapsulates the copper phase. The method for direct sintering the W&mdash;Cu&mdash;Ni alloy substantially eliminates the formation of brittle intermetallics and slumping during sintering.

Alloy for electrical contacts and electrodes and method of making

A high performance W--Cu composite powder is provided which is composed of individual particles having a tungsten phase and a copper phase wherein the tungsten phase substantially encapsulates the copper phase. The tungsten-coated copper composite powder may be pressed and sintered into W--Cu pseudoalloy articles having a homogeneous distribution of W and Cu phases without experiencing copper bleedout or it may be used in ceramic metallization for the electronics industry.

Tungsten-copper composite powder

A high performance W--Cu composite powder which is composed of individual particles having a tungsten phase and a copper phase wherein the tungsten phase substantially encapsulates the copper phase. The tungsten-coated copper composite powder may be pressed and sintered into W--Cu pseudoalloy articles having a homogeneous distribution of W and Cu phases without experiencing copper bleedout or it may be used in ceramic metallization for the electronics industry.

A method of making flowable tungsten/copper composite powder by milling an aqueous slurry of a mixture of the desired weight ratio of tungsten powder and copper oxide powder and, optionally, a small amount of cobalt powder, spray-drying the slurry to form spherical, flowable agglomerates, and reducing the agglomerates in a hydrogen atmosphere.

Method of making flowable tungsten/copper composite powder

A method for making a tungsten-copper composite oxide wherein an amount of an ammonium tungstate and an amount of an oxide or hydroxide of copper are combined without milling to form a mixture. The unmilled mixture is then dehydrated and fired at a temperature and for a time sufficient to form the tungsten-copper composite oxide.

Method of making tungsten-copper composite oxides

A method of making a tungsten-copper composite oxide wherein an amount of an oxide of tungsten and an amount of an oxide of copper are combined to form a mixture, the oxide of tungsten or the oxide of copper, or both, being in a hydrated form. The mixture is then milled, dehydrated and fired at a temperature and for a time sufficient to form the tungsten-copper composite oxide, the time sufficient to form the tungsten-copper composite oxide being at least about one-half the time sufficient to form the tungsten-copper composite oxide from a mixture of tungsten trioxide, WO.sub.3, and cupric oxide, CuO, under substantially similar conditions.

A method is disclosed for producing an agglomerated molybdenum plasma spray powder with a controlled level of oxygen which comprises forming a relatively uniform mixture of agglomerated powders containing molybdenum dioxide and one or more ammonium-containing compounds of molybdenum wherein the mixture has an oxygen content of greater than about 25% by weight and reducing the mixture in a moving bed furnace at a temperature of from about 700.degree. C. to about 1000.degree. C. for a sufficient time to remove a portion of the oxygen therefrom and form reduced molybdenum powder agglomerates having an oxygen content of no greater than about 25% by weight. The reduction takes place in the direction from the outside surface of the agglometates to the inside surface.

Method for controlling the oxygen content in agglomerated molybdenum

A method is disclosed for preparing an intimate mixture of powders of nickel-chromium-boron-silicon alloy, molybdenum metal powder, and Cr.sub.3 C.sub.2 /NiCr alloy suitable for thermal spray coatings which comprises milling a starting mixture of the above two alloys with molybdenum powder to produce a milled mixture wherein the average particle size is less than about 10 micrometers in diameter, forming an aqueous slurry of the resulting milled mixture and a binder which can be an ammoniacal molybdate compound or polyvinyl alcohol, and agglomerating the milled mixture and binder. The intimate mixture and binder may be sintered in a reducing atmosphere at a temperature of about 800.degree. C. to 950.degree. C. for a sufficient time to form a sintered partially alloyed mixture wherein the bulk density is greater than about 1.2 g/cc. The resulting sintered mixture may be entrained in an inert carrier gas, passed into a plasma flame wherein the plasma gas can be argon or a mixture of argon and hydrogen, and maintained in the plasma flame for a sufficient time to melt essentially all of the powder particles of the sintered mixture to form spherical particles of the melted portion, and to further alloy the sintered mixture, and cooled.

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Towanda, PA, United States of America

David L Houck