Influence of the Cu addition on the tribological properties of HVOF sprayed bimodal WC-Co coating

In this study, the bimodal WC-Co coatings with different Cu doping content were prepared using high-velocity oxygen-fuel (HVOF). The composition, microstructure and wear performance have been investigated. The results show that the Cu-doped WC-Co coatings consist of WC, W2C and Cu. With the increase of the Cu doping content, the hardness first increases and then decreases. The maximum value is 1254.78 +/- 66 HV0.1 when the Cu doping content is 4 wt%. The average friction coefficient and wear rate first decrease and then increase with the increasing Cu doping content. The minimum friction coefficient and wear rate are obtained at the 4 wt% doping content, the values are 0.47 +/- 0.021 and 3.38 +/- 0.25 x 10(-6) mm(3). N-1. mm(-1), respectively. The Cu embedded in the coating can form a thin self-lubricating Cu film.