Novel composite films prepared by sol-gel technology for the corrosion protection of AZ91D magnesium alloy

A novel composite films technology was developed to improve the anticorrosion performance of AZ91D magnesium alloy. The composite films were prepared via sol-gel method which is a simple application procedure within industry. The structure of xerogels and films, morphology of films were analyzed using thermo-gravimetric (TG) and differential thermal analysis (DTA), Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scan electron microscopy (SEM). The anticorrosion performance of the sol-gel coated and uncoated samples in 3.5 wt.% NaCl neutral solution had been evaluated by electrochemical tests. The results demonstrated that the composite films “Ce inner film/Mg outer film” exhibited better corrosion resistance.