The formation of metal and metal-nitride composite ultrafine powder (UFP) using a plasma jet method was examined. Pure elemental powder of Al, Fe, Cr, Cu, Ni, Si, Ti and pre-mixed elemental powders of Al-Cu, Al-Ni, Ni-Ti, Al-Ti, Si-Ti were injected into the plasma jet of Ar-N2 working gas. The main results obtained were as follows; (1) When UFP was produced from pure metal powders of Cu, Fe, Ni and Si, nitride UFP did not form at all. On the other hand, UFP of A1N, Cr
2N and TiN was formed from pure metal powders of Al, Cr and Ti, respectively. (2) Formation of nitride UFP of Si, Cr, Al, Ti was not enhanced by using working gas containing a small amount of H
2 On the contrary, AIN was eliminated by using working gas containing a small amount of H
2. (3) The structure of composite UFP of Cu-AlN and Ni-A1N consisted of two different particle types. In one type, a number of hemispherical particles was attached on the surface of a hexagonal prismatic particle. In the second type, a spherical particle was attached on one side of a cylindrical particle. (4) The structure of ultrafine composite particles of Ni-TiN consisted of three different particle types. One type was dumbbell-like and second type was dice-like morphologies. In the last type, one or two large hemispherical particles were attached on faces of a cubic particle. (5) When UFP was produced from pre-mixed powder of the Si-Ti system, string-shaped UFP was observed.
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