Inhibition of self-corrosion in magnesium by poisoning hydrogen recombination on iron impurities

► Arsenate evaluated as a corrosion inhibitor on magnesium. ► Magnesium corrosion followed by measuring evolved hydrogen. ► Arsenate found to profoundly inhibit magnesium corrosion at pH 2. ► Arsenate proposed to act by poisoning hydrogen atom recombination. ► Cathodic sites poisoned by arsenic are iron-rich second phase particles.