Wear and corrosion properties of B4C-added CoCrNiMo high-entropy alloy coatings with in-situ coherent ceramic

Abstract

In this study, a coherent ceramic strengthening wear-corrosion resistant CoCrNiMo high entropy alloy coating was successfully fabricated on 304 stainless steel (304ss) by laser cladding. Constituent phases, microstructure, and chemical composition were thoroughly investigated. The hardness and wear resistance were evaluated. Electrochemical tests were performed to measure the corrosion resistance of the passive film. The parameters of the passive films were calculated using the Mott-Schottky and the point defect model. TEM analysis was used to explain the high hardness and superior corrosion resistance on the base of the composition and boundary characteristics between different phases. Combining the results of wear and corrosion assessment, we deduce that a critical content of 2–3 at.% exists for B4C at which the best wear-corrosion tradeoff of the coating can be achieved. This strategy can be valuable in the development of both wear- and corrosion-resistant equipment in the marine environment.

Keywords

• High-entropy alloy coatings
• Wear
• Corrosion
• Laser cladding
• Coherent boundary