Corrosion Inhibition Effects of Corrosion Products on High-purity Mg and AZ91D under Thin Electrolyte Layers

In this work, the effects of deposited corrosion products on corrosion rates and pseudo-passivation behavior of high-purity (HP) Mg and AZ91D under thin electrolyte layers (TEL) and in a bulk solution were investigated. Low corrosion rates and pseudo-passive behavior can be maintained over time under TEL, especially under extremely thin electrolytes (100 μ m and 200 μ m TEL). Pseudo-passivation behavior of HP Mg under TEL is caused by the corrosion product films formed on the metal surface. The deposited corrosion products on HP Mg and AZ91D are composed of metal hydroxides, oxides and carbonates. Moreover, the pH of the TEL is lower than that in bulk solution. This might contribute to the dissolution of Mg hydroxide in the corrosion products.