Microstructure and properties of Inconel 625 + WC composite coatings prepared by laser cladding

Abstract

Inconel 625 + WC composite coatings were prepared on the surface of 2Cr13 steel by laser cladding. The microstructure, microhardness and corrosion resistance of the composite coatings with different WC contents were investigated in detail. The results show that the phase compositions of the composite coatings are mainly γ-(Ni, Fe) and various carbides. The content of WC has a significant effect on the microstructure of the cladding layers. When the WC content is 10 wt% and 15 wt%, the cladding layer has developed columnar dendrites. However, the 20 wt% WC coating is mainly composed of cellular dendrites and columnar dendrites. With the increase in WC content, the average hardness of the composite coating gradually increases. The average hardness of 20 wt% WC coating is the highest (HV1 536.98), which is a factor of 2.64 greater than that of the 2Cr13 steel matrix. Electrochemical results show that all the composite coatings have better corrosion resistance than 2Cr13 steel in 0.5 mol·L−1 HCl solution. The composite coating with 10 wt% WC has the best corrosion resistance, its corrosion potential (Ecorr) is 0.78806 V higher than that of 2Cr13 steel, and the corrosion current density (Icorr) is only 0.86% that of 2Cr13 steel.