Sumitomo Electric Industries, Limited

Minol Nakano

Akio Hara

Masaya Miyake

Takaharu Yamamoto

Mitsuo Kodama

Masaaki Tobioka

Tsuyoshi Asai

Takeshi Asai

This invention relates to a hard alloy comprising two phases: a hard phase consisting of at least one compound having a crystal structure of simple hexagonal MC type (M: metal; C: carbon) selected from the group consisting of mixed carbides, carbonitrides and carboxynitrides of molybdenum and tungsten, and a binder phase consisting of at least one element selected from the group consisting of iron, cobalt and nickel. The hard phase is prepared by carburizing an (Mo, W) alloy obtained by reducing oxides of molybdenum and tungsten with a particle size of at most 1 micron, is composed of coarse particles with a mean particle size of at least 3 microns, and has a uniform molybdenum to tungsten ratio in the particles. The hard alloy has a gross composition within the range of the shaded portion ABCDEA in FIG. 1.

Hard alloy containing molybdenum

The present invention relates to a process for the production of a solid solution constructed of at least one hard phase having a crystal structure of simple hexagonal type and selected from mixed carbides or carbonitrides of molybdenum and tungsten, which process comprises preparing an alloy powder consisting of a solid solution of molybdenum and tungsten, adding to the alloy powder carbon in an amount necessary for forming (Mo, W).sub.2 C and/or (Mo, W).sub.2 (CN), heating the mixture at a temperature at which (Mo, W).sub.2 C and/or (Mo, W).sub.2 (CN) is stable, adding to the (Mo, W).sub.2 C and/or (Mo, W).sub.2 (CN) carbon in an amount necessary for forming (Mo, W)C and/or (Mo, W)(CN) optionally with an iron group metal and then heating the mixture at a temperature at which (Mo, W)C and/or (Mo, W)(CN) is stable.

Process for the production of a hard solid solution containing molybdenum

This invention relates to a hard alloy comprising a hard phase consisting of at least one compound having a crystal structure of simple hexagonal MC type (M: metal; C: carbon) selected from the group consisting of mixed carbides, carbonitrides and carboxynitrides of molybdenum and tungsten as a predominant component, and a binder phase consisting of at least one element selected from the group consisting of iron, cobalt, nickel and chromium, in which a hard phase consisting of a compound of M.sub.2 C type having a crystal structure of hexagonal type is evenly dispersed.

Hard alloy containing molybdenum and tungsten

The present invention relates to a process for the production of an alloy powder (Mo, W) for powder metallurgy, which comprises chemically or mechanically mixing molybdenum and tungsten in the form of compounds and reducing the mixed powder with hydrogen, and a process for the production of a hard solid solution (Mo, W)C from the alloy powder (Mo, W), which comprises carburizing the alloy powder (Mo, W).

Method of making alloy and carbide powders of molybdenum and tungsten

This invention relates to a process for the production of a solid solution of compounds consisting of, in combination, at least 10 mol %, based on all metallic components, of molybdenum, at least one metallic element selected from the Group IVa, Va and VIa elements of the Periodic Table and at least one of non-metallic elements, which comprises mixing the metallic elements in the form of compounds or solutions thereof, adding carbon, optionally with at least one of non-metallic elements to the mixture, subjecting the resulting mixture to a reducing reaction with carbon and then subjecting to a solid solution-forming treatment in a reducing, carburizing or nitriding atmosphere.

Process for the production of a hard solid solution

This invention relates to surface-coated cemented carbide articles having a monolayer or multilayer consisting of one or more materials selected from oxides, carbides, nitrides and mixtures or compounds thereof, the most interior layer, in contact with the surface of the cemented carbide substrate, consisting of one or more materials selected from carbides and carbonitrides of Group IVa, Va and VIa elements, wherein the thickness of a decarburized layer (.eta. phase) present between the cemented carbide substrate and most interior coating layer is 0.5 micron or less in a case where the curvature of the interface is zero and the lattice constant of the binder metal of the coated cemented carbide article, as a mean value from the interface to 50 microns, is not more than that of the iron group metal solid solution by 0.005 A or more.

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Itami, Japan

Minol Nakano