Microstructure and properties analysis of Ni60-based/WC composite coatings prepared by laser cladding.

In this study, Ni60-WCx coatings (x = 0, 2, 4, 6 %) on 316L stainless steel (316Lss) were prepared via laser cladding technology. We examined all specimens s for microstructure, phase composition, microhardness and electrochemistry using several characterization techniques. It shows that the microstructure of the Ni-based coatings can be changed with WC powder. When the WC ratio is 2 %, crystalline crystals and cellular crystals can be found in the coating. As the WC ratio increases, more cellular crystals and fewer spiny crystals appear in the coating. When the WC ratio changes to 6 %, only cellular crystals can be found in the coating. The microhardness resultsshow that the Ni-based overcoat with added WC has a better microhardness compared to the pure Ni coating, and its average value of the coating area reaches a maximum value of 822.8 HV at a WC ratio of 2 %. That is due to the addition of WC which can cause regime transition. In addition, the Ni-based coating has better corrosion properties due to its different microstructure. When the WC ratio is 2 %, the specimen possesses the maximum Ecorr and smaller icorr with the best corrosion resistance.