The Dow Chemical Company

Omg Americas, Inc.

Other

Stephen D Dunmead

Alan W Weimer

Daniel F Carroll

Glenn A Eisman

William G Moore

Kevin J Nilsen

Kevin E Howard

Robert Thomas Nilsson

Donald R Beaman

Gene A Cochran

David W Susnitzky

Michael J Romanowski

Richard T Fox

John P Henley

Ellen M Dubensky

Hobart A Barker

Kevin C Morse

Uday V Deshmukh

Aleksander Jozef Pyzik

Harold E Rossow

Jack J Ott

Jacob A Johnson

Theresa A Guiton

Kauko J Karpale

Timothy L Allen

Karen J Buechler

Gabrielle R Lasher

Joseph F Repman

David D Mossner

Pat J DeLuca

Tom J Bunnelle

Joe F Repman

Stephen A Anderson

A method of converting metal-containing or metal alloy-containing compounds into a metal or metal alloy by rapidly heating the metal-containing or metal alloy-containing compound to an elevated temperature to instigate conversion and holding the metal-containing or metal alloy-containing compound at the elevated temperature for a time sufficient to effect formation of the metal or metal alloy is an efficient and economical method of producing metals and metal alloys.

Rapid conversion of metal-containing compounds to form metals or metal alloys

A transition metal carbide is formed from a precursor mixture comprising at least one of the group consisting of: a transition metal, a transition metal carbide and a transition metal oxide. The precursor mixture may contain the desired transition metal carbide (e.g., WC), but if the desired transition metal carbide is present in the precursor mixture, there is necessarily a significant amount of another compound such as a transition metal oxide, undesired carbide (e.g., W C) or transition metal. The method involves forming an admixture by mixing the precursor mixture with a sufficient amount of carbon to carburize the precursor mixture to the transition metal carbide and reacting the admixture in an inert or reducing atmosphere at a temperature for a time sufficient to convert the admixture to the transition metal carbide, wherein the admixture is reacted in the presence of a means to enhance transfer of heat into the admixture, an inert or reducing gas flowing through at least a portion of the admixture or combination thereof.

Method to produce a transition metal carbide from a partially reduced transition metal compound

A transition metal carbide-Group VIII metal powder comprising discrete particles of a transition metal carbide and Group VIII metal wherein: substantially all of the particles have a size of at most 0.4 micrometer; the transition metal carbide is selected from carbides of the group consisting of tungsten, titanium, tantalum, molybdenum, zirconium, hafnium, vanadium, niobium, chromium, mixtures and solid solutions thereof; and the Group VIII metal is selected from the group consisting of iron, cobalt, nickel, mixtures and solid solutions thereof. Said powders are produced by heating an admixture comprising a finishing source of carbon (e.g., acetylene black), a source of a group VIII metal (e.g., Co.sub.3 O.sub.4), and a particulate precursor to a temperature of about 1173 K to about 1773 K for a time sufficient to form a transition metal carbide-Group VIII metal powder, wherein at least about 25% by weight of the carbide precursor is carburized in forming the transition metal carbide of the transition metal carbide-Group VIII metal powder. The particulate precursor generally contains less than 2.5% oxygen by weight and contains compounds which undergo carburization such as a transition metal (e.g., W), lower valence transition metal carbide (W.sub.2 C) to form the transition metal carbide (e.g., WC)-Group VIII metal powder.

Metallic-carbide-group VIII metal powder and preparation methods thereof

A transition metal carbide (e.g., WC) is prepared by the following steps. A carbon-precursor mixture is formed by mixing a precursor comprised of (i) a transition metal oxide (e.g., WO.sub.x) and (ii) a material selected from the group consisting of: a transition metal (e.g., W); a transition metal carbide (e.g., WC) and a substoichiometric carbide (W.sub.2 C), in the presence of a source of carbon (e.g., carbon black) in an amount sufficient to form a reduced mixture comprised of the transition metal carbide and substoichiometric transition metal carbide, wherein the amount of the transition metal oxide and transition metal is essentially zero in said reduced mixture. The carbon-precursor mixture is heated in a reducing atmosphere (e.g., 5 percent hydrogen in argon) to a reducing temperature and for a time sufficient to produce the reduced mixture. The reduced mixture is milled in the presence of a source of carbon in an amount sufficient to carburize the substoichiometric transition metal carbide to form the transition metal upon heating in a reducing atmosphere. Finally, the milled reduced mixture is heated in a reducing atmosphere to a carburizing temperature that is greater than the reducing temperature for a time sufficient to carburize the substoichiometric transition metal carbide to form the transition metal carbide of this invention (e.g., WC).

Method to produce a transition metal carbide from a partially reduced

A submicrometer transition metal carbonitride is produced having the formula:

Method for making submicrometer transition metal carbonitrides

Metallic-carbide group VIII metal powder and preparation methods thereof

Aluminum nitride powder, aluminum nitride platelets, powdered solid solutions of aluminum nitride and at least one other ceramic material such as silicon carbide, and composites of aluminum nitride and transition metal borides or carbides are prepared by combustion synthesis at low gaseous nitrogen pressures. Porous bodies of aluminum nitride or composites of aluminum nitride and transition metal borides or carbides are also prepared by combustion synthesis at these pressures. The porous bodies are suitable for infiltration, either as formed or after being coated with at least one layer of a silicate material, by polymers or metals. The powders are also suitable for preparing dense sintered bodies. The aluminum nitride powder is also used to prepare AlN sintered bodies.

Aluminum nitride, aluminum nitride containing solid solutions and

Ceramic-ceramic and ceramic-metal composite materials are disclosed which contain at least two ceramic phases and at least one metallic phase. At least one of these ceramic phases is a metal boride or mixture of metal borides and another of the ceramic phases is a metallic nitride, metallic carbide, or a mixture of metallic nitride and a metallic carbide. These composite materials may be made by a combustion synthesis process which includes the step of igniting a mixture of at least one element selected from titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, aluminum and silicon, or a combination of two or more thereof, at least one boron compound selected from boron nitride, boron carbide, or a combination thereof and an ignition temperature reducing amount of a metal selected from iron, cobalt, nickel, copper, aluminum, silicon, palladium, platinum, silver, gold, ruthenium, rhodium, osmium, and iridium, or a mixture of two or more thereof, provided that at least one of the aforementioned elements is different from at least one of the aforementioned metals. This process permits a high degree of control over the microstructure of the product and relatively low pressures are required to obtain high composite material density. A densified product having high density and a finely grained microstructure may be obtained by applying mechanical pressure during combustion synthesis. The composites have improved hardness, toughness, strength, resistance to wear, and resistance to catastrophic failure.

Single step synthesis and densification of ceramic-ceramic and

A tungsten carbide-containing material in which the tungsten carbide has the general formula, W.sub.x C, wherein x is greater than one and less than two and the material has less than 0.20 weight percent cobalt, a density of at least about 97% of its theoretical density, and a Vickers hardness of at least about 2400 kg/mm.sup.2.

Sintered WC-containing materials

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

A method of forming a low level carbon high-density tungsten carbide-containing material includes sintering a preform which contains tungsten carbide powder and has a composition such that the resulting sintered material has at most 6.05 weight percent tungsten-bound carbon based on the total weight of tungsten and tungsten-bound carbon. This low level of carbon may be achieved by, prior to the sintering step, oxidizing the tungsten carbide powder sufficiently to achieve the desired substoichiometric carbon level in the sintered product or by adding a carbon-lowering material selected from the group consisting of tungsten, ditungsten carbide, and tungsten oxide. Optionally, other materials can be present in the preform such as carbon-getter metals and compounds thereof. The carbon-getter metals are those metals of which the carbides thereof are more thermodynamically stable than monotungsten carbide.

Methods for making WC-containing bodies

A multi-phase cemented ceramic article, method of making same, and the material thereof is disclosed which is useful for machining and forming of metals, including ferrous metals, titanium, aluminum and other metals. The article and its material preferably includes novel microstructures including platelets, a range of grain sizes which yields superior hardness and other characteristics, and a lower tungsten concentration within the binder phase than has been seen in the prior art. The preferred composition includes ultrafine WC, an ultrafine solid solution of (Ti, Ta, W)C, and a cobalt binder. Platelets are formed in-situ, eliminating the need to add them during manufacture for improving toughness.

Cemented ceramic article made from ultrafine solid solution powders,

A method of making metallic carbide powders includes heating a non-static solid reactant mixture of a metal oxide and a source of carbon to a first elevated temperature which is sufficient to cause at least partial carburization of the mixture. The heating is performed in a non-reducing atmosphere having a total pressure of at least one atmosphere for a sufficient time to form a partially-carburized mixture. The source of carbon is employed at a level which is less than the stoichiometric amount needed to produce the metallic carbide. The method may further include admixing a sufficient level of a source of carbon to the partially-carburized mixture to form an adjusted mixture having a total carbon content of the stoichiometric amount needed to make the metallic carbide and carburizing the adjusted mixture in a hydrogen-containing atmosphere at a second elevated temperature which is sufficient to cause the adjusted mixture to form the metallic carbide having a particle size of less than 0.2 micrometers in diameter.

Method of making metallic carbide powders

Densified micrograin refractory metal or solid solution solution (mixed

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Midland, MI, United States of America

Stephen D Dunmead