Phase evolution and wear resistance of in situ synthesized V8C7 particles reinforced Fe-based coating by laser cladding

In situ synthesized V8C7 reinforced Fe-based composite coating was successfully prepared on 35CrMo steel by laser cladding, aiming at improving the wear resistance. Constituent phases, microstructure, microhardness and wear resistance of the coating were investigated using XRD, SEM, microhardness tester and friction-wear tester. The results showed that the obtained coating was uniform and dense with no pores or cracks appearing, in addition to satisfied metallurgical bonding to the substrate. The coating was mainly composed of α-Fe, V8C7, Cr7C3, Fe3C and Mo2C phase. Fine V8C7 reinforced particles were in situ synthesized during the melting process. The shape of V8C7 particles changed from sphere to irregular blocks as a distance from the interface, which was due to the crash and binding of V8C7 particles with each other. The microhardness of coating was 775 HV0.3, which was about 4 times greater than the substrate. The wear resistance of the coating was significantly improved as indicated by the higher relative wear resistance.