Preparation of cobalt nanoparticles by direct current arc plasma evaporation method

Abstract In order to prepare cemented carbides with excellent mechanical properties, the cobalt nanoparticles were prepared by direct current (DC) arc plasma evaporation method for the first time and the effect of three adjustable parameters (current, filling pressure and the pressure ratio of hydrogen to argon ( P H2 / P Ar )) was investigated on the average diameter and the productivity through L 16 (4 3 ) orthogonal experiment in this paper. The crystalline structure, chemical composition, morphology, and particle size distribution of the samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray fluorescence analysis (XRF) and selected area electron diffraction (SAED), respectively. The results indicated that the cobalt nanoparticles achieved a high purity of 99.933 wt.% with a spherical shape, and the cobalt nanoparticles had a cubic crystal structure with a slight shrinkage in the lattice parameters. Both the average diameter and the productivity were increased with the increase of the three parameters, but the average diameter decreased when the value of P H2 / P Ar varied from 2/3 to 1. Under different technical parameters, the average diameter varied from 28 nm to 70 nm and the productivity varied from 43 g/h to 324 g/h.