Corrosion behavior of AZ91D magnesium alloy in distilled water

The corrosion of AZ91D magnesium alloy has received extensive attention due to the continuous expansion of its application field in recent years. However, the corrosion of AZ91D magnesium alloy in distilled water is relatively few. In this paper, the corrosion behavior of AZ91D magnesium alloy was studied in distilled water by electrochemical tests in combination with weight loss and surface analysis methods. The results indicated that the corrosion rate of AZ91D magnesium alloy increased with the increase of temperature and immersion time. The increase of the corrosion rate of AZ91D magnesium alloy with the increase of immersion time might be attributed to the damage of the structure of corrosion product film by hydrogen evolution, significantly accelerating the anodic process of AZ91D magnesium alloy. It was interesting that, in distilled water, the EIS of AZ91D magnesium alloy excluded an inductive arc in the low frequency region, which indicated that there was no the adsorption and desorption of aggressive ions or the damage and repair of film. The corrosion product film of AZ91D magnesium alloy in distilled water was composed of a compact inner corrosion product film and a loose outer corrosion product film.