In order to improve the wear resistance, the WC - CoCr coating prepared by HVOF with a vacuum heat treatment at different temperatures was studied in the aspects of phase structure, microstructure, hardness and friction and wear properties by means of XRD, SEM, micro - Vickers hardness tester and friction tester. Results showed that the phase composition of the coating with a heat treatment at 600 ℃ was consistent with that without heat treatment. However, when the heat treatment temperature was euqal to or higher than 750 ℃, the Co6W6C phase and Co25Cr25W8C2 phase were formed in the coating, and the contents of such phases increased with the rising of heat treatment temperature. While the temperature increased, the porosity of the coating decreased first and then increased, the hardness of the coating increased first and then decreased, and the coating with a heat treatment at 750 ℃ for 1 h obtained the maximum hardness value of 1 535 HV0.5 N. Moreover, the average friction coefficient of the coating first decreased rapidly and then tended to be stable. When the heat treatment temperature was equal to or higher than 750 ℃, the average friction coefficient of the coating decreased by about 51.8% compared with that of the untreated coating. Besides, the wear rate of the coating decreased rapidly first and then increased, and the coating with a heat treatment at 750 ℃ obtained the minimum wear rate of about 1.91 μg/m, which decreased by about 93.9% compared with that of the untreated coating.
