Metal powder particles for use in additive manufacturing are made by removing material from the surface of the particles using wet chemical etching to create a nanoscale texturing of the surface, increasing absorptivity by the metal powder particles of incident laser light and maintaining flowability. The nanoscale texturing has sub-wavelength features at laser wavelengths in the range 800-1100 nm. The particles are substantially spherical and have mean diameters in the range 10-70 μm.

Metal powder particles for use in additive manufacturing are made by removing material from the surface of the particles using wet chemical etching to create a nanoscale texturing of the surface, increasing absorptivity by the metal powder particles of incident laser light and maintaining flowability. The nanoscale texturing has sub-wavelength features at laser wavelengths in the range 800-1100 nm. The particles are substantially spherical and have mean diameters in the range 10-70 μm.

A metal magnetic powder is constituted by metal magnetic grains that each include: a metal phase where the percentage of Fe at its center part is 98 percent by mass or higher, while the mass percentage of Fe at its contour part is lower than that at the center part; and an oxide film covering the metal phase, so as to inhibit oxidation of Fe contained in the metal phase, despite the high content percentage of Fe in the metal phase.

A metal magnetic powder is constituted by metal magnetic grains that each include: a metal phase where the percentage of Fe at its center part is 98 percent by mass or higher, while the mass percentage of Fe at its contour part is lower than that at the center part; and an oxide film covering the metal phase, so as to inhibit oxidation of Fe contained in the metal phase, despite the high content percentage of Fe in the metal phase.

A metal magnetic powder is constituted by metal magnetic grains that each include: a metal phase where the mass percentage of Fe at its center part is lower than that at its contour part; and an oxide film covering the metal phase so as to allow the magnetic body resistant to magnetic saturation and low in iron loss.

A metal magnetic powder is constituted by metal magnetic grains that each include: a metal phase where the mass percentage of Fe at its center part is lower than that at its contour part; and an oxide film covering the metal phase so as to allow the magnetic body resistant to magnetic saturation and low in iron loss.

A samarium-iron-nitrogen alloy powder according to one embodiment of the present invention is characterized in that a value obtained by dividing the hydrogen content of the samarium-iron-nitrogen alloy powder by the BET specific surface area of the samarium-iron-nitrogen alloy powder is less than or equal to 400 ppm/(m.sup.2/g), and a value obtained by dividing the oxygen content of the samarium-iron-nitrogen alloy powder by the BET specific surface area of the samarium-iron-nitrogen alloy powder is less than or equal to 11,000 ppm/(m.sup.2/g).

A samarium-iron-nitrogen alloy powder according to one embodiment of the present invention is characterized in that a value obtained by dividing the hydrogen content of the samarium-iron-nitrogen alloy powder by the BET specific surface area of the samarium-iron-nitrogen alloy powder is less than or equal to 400 ppm/(m.sup.2/g), and a value obtained by dividing the oxygen content of the samarium-iron-nitrogen alloy powder by the BET specific surface area of the samarium-iron-nitrogen alloy powder is less than or equal to 11,000 ppm/(m.sup.2/g).

A samarium-iron-nitrogen alloy powder according to one embodiment of the present invention is characterized in that a value obtained by dividing the hydrogen content of the samarium-iron-nitrogen alloy powder by the BET specific surface area of the samarium-iron-nitrogen alloy powder is less than or equal to 400 ppm/(m.sup.2/g), and a value obtained by dividing the oxygen content of the samarium-iron-nitrogen alloy powder by the BET specific surface area of the samarium-iron-nitrogen alloy powder is less than or equal to 11,000 ppm/(m.sup.2/g).

There are provided reactive metal powder in-flight heat treatment processes. For example, such processes comprise providing a reactive metal powder; and contacting the reactive metal powder with at least one additive gas while carrying out said in-flight heat treatment process, thereby obtaining a raw reactive metal powder.