Microstructure and wear behavior of FeCoNiCrMn high entropy alloy coating deposited by plasma spraying

Abstract

FeCoNiCrMn high entropy alloy coatings were deposited on steel substrate by atmospheric plasma spraying at different H2 flow rates and subsequently annealed. The microstructure and the phase composition of the prepared coatings were investigated, and the hardness of the coating was determined. The wear behavior of the as-sprayed and annealed FeCoNiCrMn coatings against WC-Co ball was evaluated under dry sliding condition. The results show that the fluffy structures characterized on the surfaces of as-sprayed coatings were formed due to the volatilization and oxidation of Mn element. The coatings were single FCC phase along with some oxides. The wear rate of the as-sprayed coatings was reduced by half as the H2 flow rate increasing from 3 to 6 L/min. Annealing can greatly improve the wear resistance and scratch resistance of the as-sprayed coatings. The characterization of wear tracks demonstrates that splat spalling was the dominating wear mechanism for the as-sprayed coatings. The improvement of wear resistance by increasing H2 flow rate and annealing was attributed to the enhancement of cohesive strength among splats.