Corrosion Resistance of AZ91D Magnesium Alloy Modified by Rare Earths-Laser Surface Treatment

To improve the corrosion resistance of magnesium alloy AZ91D which is widely applied in the realm of aviation and aerospace in industry, a composite way was adopted for its surface modification, namely the laser heating of pre-coated sample by sol-gel method. Experiments for testing its corrosion resistance were carried out, accordingly, it could be concluded that this composite technique was able to improve the corrosion resistance against uniform corrosion. Surface morphology observed by SEM image was analyzed, and it could be seen clearly that laser heating was fairly favorable for improving the cohesion between coating and the substrate. XRD spectrum and BSE image were studied which gave out the information that the main compositions were mainly CeO2 and a small quantity of MgO CeO2. According to all the experimental evidence, the anticorrosion mechanism of samples treated by composite techniques and the effects of laser heating on corrosion resistance of magnesium alloys AZ91D were discussed.