Improvement in tribological properties of atmospheric plasma-sprayed WC–Co coating followed by Cu electrochemical impregnation

The WC–Co coating obtained by atmospheric plasma spraying (APS) was modified by Cu electrochemical impregnation. The copper has infiltrated into and filled up the pores in WC–Co coating. The tribological properties of the coating against the stainless steel ball as sliding pairs were investigated with a ball-on-disc (BOD) configuration in air at room temperature. The as-prepared samples were characterized by means of optical microscope, scanning electron microscope and X-ray diffraction. It was found that the frictional behavior of the WC–Co coating followed by Cu electrochemical impregnation was superior to that of WC–Co coating. The wear mechanism of the WC–Co coating followed by Cu electrochemical impregnation was microcutting, whilst that of a WC–Co coating was the fatigue wear. The improvement in tribological properties of the WC–Co coating followed by Cu electrochemical impregnation was attributed to the formation of self-lubricating Cu film on the wear surface which induces the transformation of wear mechanism.