Improving the Corrosion Resistance of AZ91 Magnesium Alloy by Surface Coating TiO2 Layers

This study adopts the sol-gel method to prepare a TiO2 coating on the surface of the AZ91 magnesium alloy, hydrolyse C16H36O4Ti to generate the TiO2 coating and form a film with excellent corrosion resistance on the surface of an AZ91 magnesium alloy. The composition, surface structure and microstructure of the TiO2 coatings are characterised via X-ray diffraction (XRD) and scanning electron microscopy. The corrosion performance of the surface coatings was investigated through hydrogen evolution experiments and electrochemical tests. The results demonstrate that TiO2 sols prepared from a mixture of hydrochloric acid, deionised water, C16H36O4Ti and anhydrous ethanol can form stable layers on the surface of an AZ91 magnesium alloy after heat treatment. The results of hydrogen evolution experiments and electrochemical tests reveal that the TiO2 coating can effectively improve the corrosion resistance of the AZ91 magnesium alloy.