First-principles calculation and experimental study on the effect of rare earth Ce and Gd on the corrosion of ZK61 magnesium alloys

Abstract This study investigates how trace Ce/Gd additions (0.5 wt%) affect the corrosion behavior of ZK61 magnesium alloy by combining first-principles calculations with experimental validation. The results reveal that both elements transform binary Mg-Zn phases into ternary Mg-Zn-RE compounds. These new phases exhibit a lower work function and electrode potential closer to the α -Mg matrix than the cathodic MgZn 2 phase, thereby reducing the micro-galvanic driving force. Consequently, the corrosion resistance is significantly improved, as confirmed by hydrogen evolution and electrochemical tests, with the performance ranking as ZK61-0.5Gd > ZK61-0.5Ce> ZK61. This work establishes a clear structure–property relationship, demonstrating that rare earth elements enhance corrosion resistance by mitigating galvanic coupling through controlled phase transformation.