Corrosion performance of a high-strength FeNiCrAl medium-entropy alloy compared with 304 stainless steel in KOH solution

The corrosion performance of high-strength FeNiCrAl medium-entropy alloy compared with that of 304 stainless steel was investigated in 1 mol/L KOH solution. The electrochemical results indicated that the FeNiCrAl medium-entropy alloy has a better corrosion resistance and lower corrosion rate. The immersion tests confirmed that the degree of corrosion of the FeNiCrAl medium-entropy alloy was less severe than that of 304 stainless steel. X-ray photoelectron spectroscopy results revealed that the higher corrosion resistance of the FeNiCrAl medium-entropy alloy results from the difference in composition of the passive films. The FeNiCrAl medium-entropy alloy promotes the enrichment of Al and Ni with an oxidation state on the surface, and it suppresses the formation of iron oxidation, inducing effective passive films with increased compactness, higher charge transfer resistance, and lower defect density. Our results are meaningful for designing and applying medium-entropy alloys with excellent corrosion resistance in alkaline media.