양극산화(Anodizing) 및 졸-겔(Sol-Gel) 공정을 이용한 AZ91D 마그네슘 합금의 내식성 향상에 대한 연구

A Study on Improving the Corrosion Resistance of AZ91D Mg Alloy by Anodizing and Sol-Gel Process

Surface treatment technology can be applied to protect magnesium alloys from corrosion. Among these techniques, anodizing treatment is one of the most promising methods for magnesium alloys. Although an anodizing treatment is usually more expensive than a chemical surface treatment, it is always selected for applications requiring high performance, such as wear resistance and heavy duty paint preparation. Ahesion of sol-gel coating to metal or metal oxide surfaces is especially favorable, because covalent bonds are formed between the substrate surface and the sol-gel film. We report a newly environmental friendly composite anti-corrosion coatings technique is developed for AZ91D magnesium alloy to improve its corrosion resistance. Silicon sol-gel coating was deposited on the anodizing layer through sol-gel technique to get a further improvement of corrosion protection for magnesium alloy. In this research, therefore, the morphologies and corrosion resistance of coatings were investigated by scanning electron microscopy(SEM), potentiodynamic polarization and salt spray testing. The experiment revealed the new coatings of alloy showed better corrosion resistance and surface morphology.