A method for finely powdering tungsten powder, which includes: a process for classifying a material tungsten powder into a fine powder having a relatively small average particle diameter and a coarse powder having a relatively large average particle diameter; an oxidation process for forming an oxide film on the particle surface of the coarse powder; and an alkali treatment process for removing the oxide film formed in the oxidation process and a natural oxide film formed on the fine powder with an alkali aqueous solution. Also disclosed is a method for producing ultrafine tungsten powder, which includes obtaining tungsten powder having an average particle diameter of 0.04 to 0.4 μm and a BET specific surface area of 5 to 15 m.sup.2/g by the above method for finely powdering.

A system and a method for selectively coating a substrate includes a removable mask including a magnetic member having a first surface contour shaped to conform to the outside surface of the substrate and a magnetizable member having a second surface contour shaped to conform to the inside surface of the substrate. The method for coating the substrate includes magnetically coupling a removable mask to at least one surface of the substrate; forming a coating of a coating material on the at least one surface of the substrate with the magnetically coupled removable mask using a bath containing the coating material; and selectively decoupling the removable mask from the at least one coated surface to reveal a portion of the coated surface without the coating.

A system and a method for selectively coating a substrate includes a removable mask including a magnetic member having a first surface contour shaped to conform to the outside surface of the substrate and a magnetizable member having a second surface contour shaped to conform to the inside surface of the substrate. The method for coating the substrate includes magnetically coupling a removable mask to at least one surface of the substrate; forming a coating of a coating material on the at least one surface of the substrate with the magnetically coupled removable mask using a bath containing the coating material; and selectively decoupling the removable mask from the at least one coated surface to reveal a portion of the coated surface without the coating.

An FeNi ordered alloy contained in a magnetic material has an L1.sub.0 ordered structure, is doped with an light element, and is provided as a granular particle. A method for manufacturing a magnetic material including an FeNi ordered alloy having an L1.sub.0 ordered structure includes preparing an FeNi ordered alloy provided as a granular particle, and doping a light element into the FeNi ordered alloy.

A steel for a carburizing and a carburized steel component having a steel portion and a carburized layer with a thickness of more than 0.4 mm to less than 2 mm which is formed on an outside of the steel portion. A chemical composition of the steel for the carburizing and the steel portion of the carburized steel component satisfies simultaneously equations of a hardness parameter, a hardenability parameter, and a TiC precipitation parameter.

A steel for a carburizing and a carburized steel component having a steel portion and a carburized layer with a thickness of more than 0.4 mm to less than 2 mm which is formed on an outside of the steel portion. A chemical composition of the steel for the carburizing and the steel portion of the carburized steel component satisfies simultaneously equations of a hardness parameter, a hardenability parameter, and a TiC precipitation parameter.

A steel for a carburizing and a carburized steel component having a steel portion and a carburized layer with a thickness of more than 0.4 mm to less than 2 mm which is formed on an outside of the steel portion. A chemical composition of the steel for the carburizing and the steel portion of the carburized steel component satisfies simultaneously equations of a hardness parameter, a hardenability parameter, and an AlN precipitation parameter.

A steel for a carburizing and a carburized steel component having a steel portion and a carburized layer with a thickness of more than 0.4 mm to less than 2 mm which is formed on an outside of the steel portion. A chemical composition of the steel for the carburizing and the steel portion of the carburized steel component satisfies simultaneously equations of a hardness parameter, a hardenability parameter, and an AlN precipitation parameter.

Provide a metal surface reforming method enabling metallic products with superior characteristics such as surface hardness, heat resistance, corrosion resistance, high temperature oxidation, high temperature corrosion, and environmental corrosion and the like.

Halogenation treatment of heating and retaining a base material in an atmosphere containing a halogen based gas is performed on a base material of iron based metal or nickel based metal, then nitride processing of heating and retaining the halogenated base material described above in an atmosphere containing a nitrogen source gas is performed, then chromizing treatment is performed by placing the nitrided base material in a powder containing metal chromium powder to form a surface reformed layer on the base material described above. These metallic products obtained have high hardness, superior heat resistance and corrosion resistance, and exhibit superior performance in high temperature oxidation, high temperature corrosion, erosion, and cavitation and the like environments. Further, the metallic products described above exhibit superior performance in acid or alkali environments, neutral environments, and corrosive environments such as chlorides like salt water.

A high surface-pressure resistant component includes a steel having a composition containing, in mass %, 0.17-0.23% of C, 0.80-1.00% of Si, 0.65-1.00% of Mn, 0.030% or less of P, 0.030% or less of S, 0.01-1.00% of Cu, 0.01-3.00% of Ni, and 0.80-1.00% of Cr, with the remainder being Fe and unavoidable impurities, in which the surface layer C concentration of a carburized and quenched layer is 0.70-0.80% in mass %.