Effect of WC-Co and 86WC-10Co-4Cr coatings on type-II hot corrosion behaviour & microstructure characteristics at 650 degree celsius

Abstract

In this study, WC-Co and 86WC-10Co-4Cr coatings were applied on the AISI316 stainless steel by HVOF with Fe2 (SO4)3‐12%Na2SO4 corrosive environment at 650 °C. Measurements of the weight change were taken after every cycle for a total of fifty cycles to provide an approximation of the kinetics of the corrosion. This coating increases the corrosion resistance of surfaces. The surface morphology and phases produced during hot corrosion were investigated using EDS, XRD, and field emission SEM. The oxides of the surface coatings were high in Cr and W. These oxides contributed to hot corrosion resistance in corrosive environments by acting as barriers to corrosive element penetration/diffusion employing coatings. The greater tungsten the coating's content improved corrosion resistance at high temperatures. The coating's chromium (Cr) induced the growth of spinel NiCr2O4 and Cr2O3, which also contributes to maintaining corrosion resistance. Some oxides, including FeSCr2S3, Na2FeO2, and FeS, were discovered. The examination of the data confirmed that HVOF 86WC-10Co-4Cr sprayed on AISI316L stainless steel had shown high type-II hot corrosion resistance compared to WC-Co, although both coatings provide improved resistance to corrosion for sprayed base metal versus the bare base metal.