Effects of structure and processing technique on the properties of thermal spray WC–Co and NiCrAl/WC–Co coatings

Single-layered coatings of WC–Co and multi-layered coatings of NiCrAl/WC–Co were manufactured by high-velocity oxy-fuel (HVOF) and detonation spraying (DS) techniques. The residual stress, mechanical properties, and wear resistance of these coatings were evaluated and the effects of coating structure and spraying method on coating properties were analyzed. Experimental results show that the coatings made by HVOF excel corresponding DS coatings with respect to mechanical and thermal shock properties. Both the spraying method and coating structure affect the residual stress markedly. Compared with the single-layered coatings, multi-layered ones exhibit better wear resistance under light-load conditions.