A process for producing nickel particles comprises the steps of: melting a nickel source to produce a melt; and powderizing molten nickel contained in the melt by an atomization method comprising atomizing a gas or an aqueous medium onto the melt, thereby producing nickel particles having purity of 90% or more. In the production process, it is also possible to melt a metal that is more likely to be oxidized than nickel together with the nickel source and then remove an oxide of the metal which is produced as the result of the melting.

A method of fabricating a material having a high concentration of a carbide constituent. The method may comprise adding a carbide source to a biocompatible material in which a weight of the carbide source is at least approximately 10% of the total weight, heating the carbide source and the biocompatible material to a predetermined temperature to melt the biocompatible material and allow the carbide source to go into solution to form a molten homogeneous solution, and impinging the molten homogeneous solution with a high pressure fluid to form spray atomized powder having carbide particles. The size of a particle of carbide in the atomized powder may be approximately 900 nanometers or less. The biocompatible material may be cobalt chrome, the carbide source may be graphite, and the fluid may be a gas or a liquid.

Provided is a low thermal expansion alloy that contains, in mass %, not more than 0.015% of C, not more than 0.10% of Si, not more than 0.15% of Mn, 35.0-37.0% of Ni, and less than 2.0% of Co. Ni+0.8Co is 35.0-37.0%, and the remaining portion is Fe and unavoidable impurities. The low thermal expansion alloy has a solidification structure in which the secondary dendrite-arm spacing is 5 μm or less, has an average thermal expansion coefficient in a range of 0±0.2 ppm/° C. at 100° C. to −70° C., and has an Ms point of −196° C. or less.

Provided is a low thermal expansion alloy that contains, in mass %, not more than 0.015% of C, not more than 0.10% of Si, not more than 0.15% of Mn, 35.0-37.0% of Ni, and less than 2.0% of Co. Ni+0.8Co is 35.0-37.0%, and the remaining portion is Fe and unavoidable impurities. The low thermal expansion alloy has a solidification structure in which the secondary dendrite-arm spacing is 5 μm or less, has an average thermal expansion coefficient in a range of 0±0.2 ppm/° C. at 100° C. to −70° C., and has an Ms point of −196° C. or less.

An object is to provide an alloy composition that has a sufficient melting point for casting of an aluminum alloy, also has high hardness, and can suppress an occurrence of galling. The alloy composition of the present invention includes: a Mo—Cr-based dendritic structure 3; and a Ni—Al-based interdendritic structure 5 that fills a periphery of the Mo—Cr-based dendritic structure 3. The alloy composition of the present invention can adopt a chemical composition I in which when Mo+Cr+Ni+Al=100 at. % holds, Ni+Al=15 to 50 at. % and Mo+Cr=50 to 85 at. % hold; or a chemical composition II in which Ni+Al=40 to 70 at. % and Mo+Cr=30 to 60 at. % hold.

The invention relates to an alloy produced by powder metallurgy and having a non-amorphous matrix, the alloy consists of in weight % (wt. %): C 0-2.5 Si 0-2.5 Mn 0-15 Cr 0-25 Mo 4-35 B 0.2-2.8 optional elements, balance Fe and/or Ni apart from impurities, wherein the alloy comprises 3-35 volume % hard phase particles, the hard phase particles comprises at least one of borides, nitrides, carbides and/or combinations thereof, at least 90% of the hard phase particles have a size of less than 5 μm and at least 50% of the hard phase particles have a size in the range of 0.3-3 μm.

The invention relates to an alloy produced by powder metallurgy and having a non-amorphous matrix, the alloy consists of in weight % (wt. %): C 0-2.5 Si 0-2.5 Mn 0-15 Cr 0-25 Mo 4-35 B 0.2-2.8 optional elements, balance Fe and/or Ni apart from impurities, wherein the alloy comprises 3-35 volume % hard phase particles, the hard phase particles comprises at least one of borides, nitrides, carbides and/or combinations thereof, at least 90% of the hard phase particles have a size of less than 5 μm and at least 50% of the hard phase particles have a size in the range of 0.3-3 μm.

An L10-FeNi magnetic powder has an average particle size of 50 nm to 1 μm, and an average value of sphericity P of 0.9 or more. The sphericity P is defined as P=Ls/Lr, where Lr is a perimeter of an L10-FeNi magnetic powder particle on an image of a microscope, and Ls is a perimeter of a perfect circle that has a same area as the L10-FeNi magnetic powder particle on the image for which Lr is calculated.

An L10-FeNi magnetic powder has an average particle size of 50 nm to 1 μm, and an average value of sphericity P of 0.9 or more. The sphericity P is defined as P=Ls/Lr, where Lr is a perimeter of an L10-FeNi magnetic powder particle on an image of a microscope, and Ls is a perimeter of a perfect circle that has a same area as the L10-FeNi magnetic powder particle on the image for which Lr is calculated.

A metal powder for powder metallurgy according to the invention contains Co as a principal component, Cr in a proportion of 25 to 32 mass %, Ni in a proportion of 5 to 15 mass %, Fe in a proportion of 0.5 to 2 mass %, W in a proportion of 4 to 10 mass %, Si in a proportion of 0.3 mass % to 1.5 mass %, and C in a proportion of 0.05 mass % to 0.8 mass %, wherein when one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta is defined as a first element, and one element selected from the group and having a higher group number in the periodic table than that of the first element or having the same group number as that of the first element and a higher period number than that of the first element is defined as a second element, the first element is contained in a proportion of 0.01 to 0.5 mass %, and the second element is contained in a proportion of 0.01 to 0.5 mass %.