New understanding on the mechanism of organic inhibitors for magnesium alloy

The effect of inhibitors on the corrosion behavior of AZ91D magnesium (Mg) alloy was investigated via a combination of experimental and computational approaches. A new inhibition mechanism was proposed that the nucleation of corrosion products affected by inhibitor. The Mg(OH)2 embryos carry positive charges during the metal dissolution process because the pH is lower than the isoelectric point. The positively charged embryos suppress the crystal nucleation, indicating that the inhibitor with negative charges can adsorb on the embryos, resulting in the acceleration of the embryo growths. Consequently, a dense corrosion product film and superior inhibition efficiency were obtained.