Silicon carbide particles have been covered with an alumina or stainlees 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 is found that the mechanical energy input induces a nearly rounded shape of the final composite particles with a controlled composite size. However the SiC inner particles still retain some evidence of prismatic geometry due to neither a milling effect nor the formation of new phases that usually takes place during the mechanofusion process. The new roundly-shaped composite particles were sprayed in air with a direct current plasma gun working with an Ar/H-2 mixture as plasma forming gas. The influence of the chemical composition of the protective shell on the thermal spraying deposit properties is also discussed in this paper.