Preparation and Corrosion Resistance of Magnesium Coatings by Magnetron Sputtering Deposition

Magnesium coatings were fabricated on stainless steel substrates (1Cr11Ni2W2MoV) by a plane magnetron sputtering technique. The argon pressure and the substrate condition (including temperature and the substrate was rotated or fixed) were varied in order to evaluate the influence of the parameters on the crystal orientation and morphology of the coating. The corrosion behavior of the coatings in 1 wt pct NaCI solution was studied by electrochemical methods. The results showed that all coatings exhibited preferred orientation (002) as the argon pressure increased from 0.2 to 0.4 Pa. The morphologies of the coatings varied with the argon pressure and with whether the substrate was rotated or fixed. The open circuit potential of the coatings was more positive than that of cast AZ91D magnesium alloy. However, the immersion test in 1 wt pct NaCI solution showed that the corrosion rates of the coatings were higher than that of cast AZ91D magnesium alloy.