The effect of reactive elements on surface oxidation of a CoCrFeNi high-entropy alloy

Reactive element (RE) additions are widely known to improve the oxidation resistance of structural alloys in high-temperature applications, yet their atomistic role in oxide formation and adhesion remains unclear. Herein, first-principles calculations were employed to reveal the mechanistic influence of selected RE on the surface oxidation of a CoCrFeNi high-entropy alloy. REs were found to improve oxygen binding strength, facilitate charge transfer at the metal-oxide interface, reduce activation energy for oxygen diffusion, promote early-stage oxide nucleation, and improve scale adherence. Our findings bridge experimental observations with atomistic theory, offering insight for the design of oxidation-resistant materials capable of withstanding harsh environments.