Spatial composition distribution of a Ni-Cu binary alloy powder in a thermal plasma process

Abstract

The composition of nanoparticles obtained by a thermal plasma process was quantitatively investigated using a Ni-Cu isomorphous alloy system. Specifically, a Ni-Cu alloy nanopowder with an average particle diameter of ~ 70 nm was prepared by the thermal plasma process and the particle composition was investigated. As the lattice constant follows the Vegard's law, a nanopowder with an average composition equivalent to the predefined composition was successfully obtained. According to the EDS analysis obtained from each particle, the standard deviation of composition distribution was 7.7 at% as a powder. The computational study indicated that each particle has a homogeneous composition because of the nanoparticle formation via nanodroplet and that a composition distribution of 1.05 at% is estimated in the powder. Further, the spatial composition distribution of the alloy powder in the reaction chamber was experimentally studied by trapping the powder at a certain location, and the results indicated that the composition distribution of the powder varied spatially.