Corrosion behavior of AZ91D magnesium alloy in 60% ethylene glycol aqueous solution containing trace Cl - and Cu 2+ were systematically investigated using weight loss measurements, white light interferometry, and electrochemical analysis. Key findings reveal that: Corrosion acceleration efficacy follows: Cu 2+ < Cl - < Cl - +Cu 2+ . Specifically, the corrosion rate in the coexistence of Cl - and Cu 2+ is 10.12% higher than that in the presence of Cl - alone; the depth and diameter of Q3 pits increase by 12.74% and 50.43%, respectively, manifesting that the coexistence of two ions primarily exacerbates pitting severity. Mechanistically, cathodically deposited Cu particles induce microcrack formation and form micro-galvanic couples with the Mg matrix, thereby accelerating the corrosion rate. Furthermore, the synergistic attack of Cl - and embedded Cu particles severely impairs the integrity of the corrosion product film, which sustains the galvanic acceleration effect of Cu particles and ultimately leads to intensified pitting corrosion.
Hu et al. (Thu,) studied this question.