High‐Temperature Galvanic Corrosion Behavior of AZ31B Mg Alloy and ADC12 Al Alloy in Deionized Water

ABSTRACT In this paper, the high‐temperature galvanic corrosion behavior of AZ31B Mg alloy and ADC12 Al alloy in deionized water was investigated using electrochemical methods, weight loss experiments, and surface characterization techniques. The results showed that high temperature and the galvanic effect simultaneously altered the galvanic corrosion behavior between them, and accelerated synchronously their corrosion. Specifically, at high temperature, the Mg alloy surface film was severely damaged by vigorous hydrogen evolution reaction, and the enhanced alkalinity of deionized water promoted the dissolution of passivation film and matrix. The 24‐h weight loss tests and 120‐h electrochemical tests showed that with the increase in test duration, high‐temperature galvanic corrosion made their corrosion product film thicker and denser, while vigorous hydrogen evolution subsequently damaged the corrosion product film on the Mg alloy surface, accompanied by a higher galvanic corrosion rate between them. The corrosion products for the Mg alloy consisted of MgO, Mg(OH)₂, and Al(OH)₃, while the corrosion products for the Al alloy were primarily Al₂O₃ and Al(OH)₃.