Microstructures and tribological properties of plasma sprayed WC–Co–Cu–BaF2/CaF2 self-lubricating wear resistant coatings

A promising WC–Co–Cu–BaF2/CaF2 self-lubricating wear resistant coating was deposited via atmospheric plasma spraying (APS) process by using homemade feedstock powders composed of WC–Co, Cu and BaF2/CaF2 eutectic. The as-prepared cermet coatings had better frictional behavior comparing with the WC–Co coating. Moreover, the often-occurred decarburization of WC in APS process was noticeably improved due to the binding of copper and BaF2/CaF2 phase, which not only offered effective solid lubrication, but also acted as bind phases to mend the microstructure and protected WC from decomposition. The optimized specimen contained 10 wt.% Cu and 10 wt.% BaF2/CaF2 in a WC–Co matrix, which had excellent frictional and wear performance. The wear mechanism of the self-lubricating wear resistant coating was discussed with the microstructures, compositions and mechanical properties of the composite materials in detail.