Sulfurizing of CoCrFeNiSi0.4 and CoCrFeMoNi high entropy alloys fabricated by laser cladding.

The ion sulfurizing technique was carried out on CoCrFeNiSi 0.4 and CoCrFeMoNi high entropy alloys (HEAs), the microstructures and tribological properties of the HEAs before and after sulfurization were tested and analyzed. Results indicated that the CoCrFeNiSi 0.4 and CoCrFeMoNi HEAs were both dominated by FCC solid solution. After sulfurization, the FeS and FeS/MoS 2 multisulfides lubricant films with thickness around 4 μm were successfully fabricated on CoCrFeNiSi 0.4 and CoCrFeMoNi HEAs, respectively. The grains of FeS/MoS 2 multisulfides films were more compact than those of single FeS films. After sulfurization, the friction coefficients of CoCrFeNiSi 0.4 and CoCrFeMoNi HEAs were decreased from 0.6 and 0.47 to 0.152 and 0.12, respectively. Because of the effectively synergistic work of FeS and MoS 2 lubricant phases, the FeS/MoS 2 multisulfides films performed lower stable friction coefficient (0.12) and weight loss (4.25 mg) than single FeS films, which were 0.152 and 5.9 mg, respectively. Unlabelled Image • The HEAs were firstly applied combining the ion sulfurizing technique. • The FeS/MoS 2 multisulfides lubricant films were fabricated on CoCrFeMoNi HEA. • The frictional properties of the HEAs were improved greatly by ion sulfurization. • The differences on frictional properties of FeS and FeS/MoS 2 films were discussed. [ABSTRACT FROM AUTHOR]