INFLUENCE OF MECHANOFUSED CARBIDE-OXIDE AND CARBIDE-METAL POWDERS ON PLASMA SPRAYED DEPOSITS

摘要

Silicon carbide particles have been covered with an alumina or a stainless steel shell by the mechanofusion process in order to avoid or at least to limit their chemical decomposition during their flight in a plasma jet flowing in air. It was found that the mechanical energy input induced a spherical shape of the final composite particles with a controlled shell thickness. However the SiC particles still retained some evidence of prismatic geometry because no milling effect or formation of new phases occurring during the mechanofusion process could be detected. The new spherical-shaped composite particles were sprayed in air with a D.C. plasma gun working with an Ar/H_2 mixture as plasma forming gas. The influence of the chemical composition of the covering layer on the plasma sprayed deposit properties is discussed in this paper.