Abrasive wear behavior of bimodal WC-CoCr coatings sprayed by high velocity oxy-fuel

WC-CoCr composite coatings in bimodal and conventional structures were deposited by high velocity oxy-fuel (HVOF), respectively. The microstructure, microhardness, and fracture toughness of the coatings with different WC particle size distributions were studied, the coating abrasive wear characteristics were carried out by dry-sand rubber wheel abrasion tester, and the wear failure mechanisms of the coatings were investigated. The results show that, the bimodal structure coating fabricated by the powder containing 30wt% ultrafine WC particles demonstrates the most dissolution of WC in binder during deposition and the lowest coating fracture toughness. However, the bimodal structure coating fabricated by the powder containing 50wt% ultrafine WC particles combines the least porosity, the greatest microhardness and fracture toughness, and the most superior wear resistance.