Influence of coating microstructure on the abrasive wear resistance of WC/Co cermet coatings

Thermally sprayed WC/Co cermet coatings are widely used for their resistance to abrasive wear. In this work the influence of the abrasive grain size on the abrasive wear resistance was investigated for WC/Co coatings sprayed with several processes: APS, high-velocity oxy-fuel (HVOF) and VPS. Results show that the larger the abrasive particle size, the lower the abrasion resistance of the coatings. Moreover, among the thermal spray techniques tested, HVOF coatings have the best wear resistance while VPS coatings present the lowest resistance. The role of the coating microstructure and residual stresses on the wear track and morphologies, as well as the abrasive wear behaviour, are discussed.