A method of manufacture comprising: controlling provision of a first mould part including an inner surface defining a first cavity, the inner surface of the first mould part comprising a plurality of first grooves; controlling provision of a second mould part including an inner surface defining a second cavity, the inner surface of the second mould part comprising a plurality of second grooves; controlling coupling of the first mould part and the second mould part, the first cavity and the second cavity forming a third cavity, the plurality of first grooves and the plurality of second grooves forming a double helical pattern; controlling provision of a powder to the third cavity; and controlling cold isostatic pressing of the powder within the third cavity to form a double helical gear.

A method of fabricating a metal matrix composite (MMC) tool includes coating at least a portion of an interior of a mold assembly with one or more layers of a material coating, where the mold assembly defines at least a portion of an infiltration chamber. Reinforcing materials are deposited into the infiltration chamber, and infiltrated with a binder material. One or more layers of the material coating may then be reacted with the binder material to form an outer shell on selected outer surfaces of the MMC tool.

A composite is obtained by press-molding a mixed powder comprising 20-50 vol % of a metal powder and 50-80 vol % of a diamond powder for which a first peak in a volumetric distribution of particle size lies at 5-25 m, and a second peak lies at 55-195 m, and a ratio between the area of a volumetric distribution of particle sizes of 1-35 m and the area of a volumetric distribution of particle sizes of 45-205 m is from 1:9 to 4:6, thereby obtaining a composite having a high thermal conductivity and a coefficient of thermal expansion close to that of semiconductor devices, which is easy to mold into a prescribed shape.

A composite is obtained by press-molding a mixed powder comprising 20-50 vol % of a metal powder and 50-80 vol % of a diamond powder for which a first peak in a volumetric distribution of particle size lies at 5-25 m, and a second peak lies at 55-195 m, and a ratio between the area of a volumetric distribution of particle sizes of 1-35 m and the area of a volumetric distribution of particle sizes of 45-205 m is from 1:9 to 4:6, thereby obtaining a composite having a high thermal conductivity and a coefficient of thermal expansion close to that of semiconductor devices, which is easy to mold into a prescribed shape.

An object of the invention is to provide a method that is for manufacturing a powder magnetic core through simple compression molding and capable of manufacturing a complicatedly shaped powder magnetic core with reliable high strength and insulating properties. The invention is directed to a method for manufacturing a powder magnetic core with a metallic soft magnetic material powder, the method including: a first step including mixing a soft magnetic material powder and a binder; a second step including compression molding the mixture obtained after the first step; a third step including performing at least one of grinding and cutting on the compact obtained after the second step; and a fourth step including heat-treating the compact after the third step, wherein in the fourth step, the compact is heat-treated so that an oxide layer containing an element constituting the soft magnetic material powder is formed on the surface of the soft magnetic material powder.

An object of the invention is to provide a method that is for manufacturing a powder magnetic core through simple compression molding and capable of manufacturing a complicatedly shaped powder magnetic core with reliable high strength and insulating properties. The invention is directed to a method for manufacturing a powder magnetic core with a metallic soft magnetic material powder, the method including: a first step including mixing a soft magnetic material powder and a binder; a second step including compression molding the mixture obtained after the first step; a third step including performing at least one of grinding and cutting on the compact obtained after the second step; and a fourth step including heat-treating the compact after the third step, wherein in the fourth step, the compact is heat-treated so that an oxide layer containing an element constituting the soft magnetic material powder is formed on the surface of the soft magnetic material powder.

A method for manufacturing a powder for magnetic cores includes: a calcination step for heating a first powder composed of an iron alloy containing Si at 975? C. to 1175? C. to obtain a calcined body; a cracking step for disintegrating the calcined body to obtain a second powder; and a powder annealing step for annealing the second powder to obtain a third powder. The powder annealing step is performed, for example, by heating the second powder at 550? C. to 850? C. The third powder is composed, for example, of soft magnetic particles satisfying an average particle diameter of 50 to 250 ?m, an average crystal particle diameter of 30 to 100 ?m, and an average particle hardness of 100 to 190 Hv. Such a dust core is suitable, for example, when used in an alternating magnetic field having a frequency of 1 to 3 kHz.

A method for manufacturing a powder for magnetic cores includes: a calcination step for heating a first powder composed of an iron alloy containing Si at 975? C. to 1175? C. to obtain a calcined body; a cracking step for disintegrating the calcined body to obtain a second powder; and a powder annealing step for annealing the second powder to obtain a third powder. The powder annealing step is performed, for example, by heating the second powder at 550? C. to 850? C. The third powder is composed, for example, of soft magnetic particles satisfying an average particle diameter of 50 to 250 ?m, an average crystal particle diameter of 30 to 100 ?m, and an average particle hardness of 100 to 190 Hv. Such a dust core is suitable, for example, when used in an alternating magnetic field having a frequency of 1 to 3 kHz.

A sintered compact having a density of 7.5 g/cm.sup.3 or more is formed by mixed powder. The mixed powder is obtained by mixing graphite powder having an average particle diameter of 8 m or less and diffusion alloyed steel powder. The ratio of the graphite powder is from 0.05 wt % to 0.35 wt % with respect to 100 wt % of the diffusion alloyed steel powder. Or, the mixed powder is obtained by mixing the graphite powder and completely alloyed steel powder. The ratio of the graphite powder is from 0.15 wt % to 0.35 wt % with respect to 100 wt % of the completely alloyed steel powder.

A cermet and a cutting tool are provided which have high wear resistance and high fracture resistance at a cutting edge even in a mode of cutting where the cutting edge comes to have a high temperature. A cermet 1 includes a hard phase 2 including a carbonitride of one or more kinds of metals selected from Group 4, Group 5, and Group 6 metals of the periodic table including at least Ti and a binder phase 3 containing W and at least one kind of a metal selected from Co and Ni, wherein the binder phase 3 includes a first binder phase 4 in which a mass ratio of W to a total amount of Co and Ni (W/(Co+Ni)) is 0.8 or less and a second binder phase 5 in which a mass ratio of W to a total amount of Co and Ni (W/(Co+Ni)) is 1.2 or more.