Corrosion-resistant Cu-Fe-based immiscible medium-entropy alloy with tri-layer passivation

Abstract Here, a novel alloy design strategy for improving corrosion resistance of Al15(CuFeMn)85 (at%) immiscible dual-phase medium-entropy alloy is proposed and verified experimentally. The corrosion resistance of the alloy significantly enhances with the addition of Cr. During the corrosion of the Cr-containing alloy, three different oxide layers of Cu-, Cr-, and Fe-rich oxide layers with a few nm thickness are sequentially formed as a layered structure. Such tri-layer oxide enhances corrosion resistance by shielding the surface of the matrix, and the corrosion resistance of the alloys is comparable to that of austenitic stainless steels.