The Dow Chemical Company

Glenn A Eisman

Alan W Weimer

Gene A Cochran

John P Henley

Robert D Door

Stephen D Dunmead

Donald R Beaman

Kevin J Nilsen

Daniel F Carroll

David W Susnitzky

Yu-Min Tsou

William G Moore

David A Dunn

Selim Yalvac

Robert A Kirchhoff

Kevin E Howard

Lloyd E Alexander

Brian M Banker

Matthew R Kesterson

The invention is a process for the preparation of coated nitride powder, comprising contacting one or more metal complex(es), organo-aluminum material, optionally one or more silicon compounds or mixtures thereof, with nitride powder under conditions such that coated nitride powder is formed. A metal complex is a metal-containing system which is soluble in a host liquid. The process of the invention is a process for making coated nitride powder and obtaining the desirable properties of coated nitride powder, while maintaining the desirable properties of the uncoated powder, such as good thermal conductivity, for use in electronic applications. In another aspect, the invention is a coated nitride powder which has the advantageous properties of the uncoated powder and is a desirable alternative to current nitride coatings.

Method of preparing coated nitride powder and the coated powder produced

Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.

Silicon nitride/silicon carbide composite densified materials prepared

Carbothermally reduce a metal oxide to its corresponding metal nitride or metal carbide powder in a vertical gravity flow reactor by adding precursor pellets containing the metal oxide, a thermally decomposed binder material and carbon or a source of carbon directly to a heated reaction zone within the reactor. The pellets form a pellet bed, the top of which must be maintained within the heated reaction zone. The binder material is a blend of wheat and corn starches, optionally in conjunction with another binder such as melamine. The binder material thermally decomposes to a carbonaceous residue which functions both as an additional source of carbon and as a binder for the precursor pellets. The reactor may be modified by adding an internal vent line to remove volatile materials from the heated reaction zone before they have an opportunity to condense on internal reactor surfaces.

Moving bed process for carbothermally synthesizing nonoxide ceramic

Silicon carbide/silicon nitride composites are prepared by carbothermal reduction of crystalline silica powder, carbon powder and optionally crsytalline silicon nitride powder. The crystalline silicon carbide portion of the composite has a mean number diameter less than about 700 nanometers and contains nitrogen.

Method for producing silicon nitride/silicon carbide composite

Silicon nitride/silicon carbide composite powders

An electrochemical cell having at least one electrode containing a carbon fiber paper coated with an uncoagulated mixture of binder and catalytically active metal particles provides superior voltage characteristics at catalyst/binder ratios of about 2/1 to about 25/1.

Electrochemical cell having an electrode containing a carbon fiber paper

A method for making submicrometer metallic carbides and submicrometer solid solution metallic carbides from sources of at least one metallic oxide and carbon involves the rapid heating of a reactive particulate mixture of at least one metallic oxide and carbon in order to achieve a resulting particulate size of less than 1 micrometer. Submicrometer sized metallic carbides and solid solution metallic carbides have found great use in commercial ceramic applications. It has been found that the smaller sized particles produce a product having superior toughness and hardness. In addition, the submicrometer sized solid solution metallic carbide resulting from this method is also disclosed.

Method for making submicrometer carbides, submicrometer solid solution

A supported catalyst useful in the preparation of an electrode for an electrochemical cell which comprises the residue remaining after heating at about 500.degree. to about 800.degree. C. a transition metal and a polymer such as polyvinylpyridine all adsorbed on a support material. Useful electrodes are prepared by combining the supported catalyst with a current collector.

Electrochemical cell electrode

An ion exchange membrane/electrode assembly having increased efficiency in proton exchange processes as the result of membrane hydration processing comprising heating a membrane/electrode assembly at elevated temperature and pressure so as to provide increased hydration levels of the membrane.

Ion exchange membrane/electrode assembly having increased efficiency in

Rapidly heat powdered aluminum, an admixture of powdered aluminum and a compatible solid material, a powdered admixture of alumina and carbon, or aluminum nitride powder having a surface area lower than desired in the presence of a source of nitrogen at a temperature of 2473 to 3073K to produce aluminum nitride, then promptly quench the aluminum nitride product. The product has a surface area of greater than 10 m.sup.2 /g, preferably greater than 15 m.sup.2 /g.

Process for preparing ultrafine aluminum nitride powder

A supported catalyst useful in the preparation of an electrode for an electrochemical cell which comprises the residue remaining after heating at about 500.degree. to about 700.degree. C. a transition metal and a polymer such as polyvinylpyridine all adsorbed on a support material. Useful electrodes are prepared by combining the supported catalyst with a current collector.

An ion exchange membrane or ion exchange membrane/electrode assembly having increased efficiency in proton exchange processes as the result of membrane hydration processing comprising heating a hermetically sealed membrane or membrane/electrode assembly at elevated temperature and pressure so as to provide increased hydration levels of the membrane.

Ion exchange membrane having increased efficiency in proton exchange

A method for rejuvenating a membrane or diaphragm from an electrochemical cell which comprises the steps of treating the membrane or disphragm with an inorganic acid at an elevated temperature so as to dissolve metallic particles and then optionally treating the membrane or diaphragm with a basic solution. Metals dissolved in the acid solution can be recovered by conventional methods.

Method for the recovery of metals from the membrane of electrochemical

Rapidly heat powdered aluminum in the presence of a source of nitrogen at a temperature of 1873 to 2373 K. to produce aluminum nitride, then promptly quench the aluminum nitride product. The product has a surface area between 2 and 8 square meters per gram and an oxygen content of less than 1.2 weight percent.

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Midland, MI, United States of America

Glenn A Eisman