Optimizing 304 Stainless Steel Surface Performance with CoCrFeMoNi High-Entropy Alloy Coating via Gas Tungsten Arc Cladding

Abstract

CoCrFeMoNi high entropy alloy (HEA) coatings were fabricated on the surface of the 304 stainless steel (304SS) via argon tungsten arc cladding process. The microstructure, micro-hardness and tribological performance, and corrosion behavior of the HEA coatings were investigated. Results indicate the boundary between the coating and the substrate shows a metallurgical bonding. The properties of CoCrFeMoNi HEA coatings are closely correlated with the process parameters. A maximum average hardness of 585 HV was obtained, which is about 3 times that of the substrate, and this verifies surface strengthening effect of CoCrFeMoNi HEA. Most of the coatings show better wear resistance than the substrate; that is, the minimum volume wear rate of coating reduced by 58% compared to the substrate. In addition, CoCrFeMoNi HEA coatings show similar corrosion voltage and current values to 304SS in 3.5 wt.% NaCl solution. A broader passivation zone and pitting resistance have been obtained, showing a better passivation film formation ability and resistance to pit corrosion as compared to 304SS. Overall, the optimal performance of the CoCrFeMoNi HEA coatings was obtained at an electric current density of 125A, arc scanning rate of 60 mm/min and argon flow of 10 L/min. Surface optimization of 304SS can be achieved through argon tungsten arc cladding CoCrFeMoNi HEA coating.