Corrosion protection properties of anodic oxide coatings on an Al–Si alloy

In this study, aluminum oxide coatings were deposited on Al–Si alloy substrates to produce hard and corrosion protective films using three different techniques: hard anodizing (HA), anodizing (A), and modified anodizing (MA). Potentiodynamic polarization tests were conducted to assess the corrosion resistance of the coatings. A microhardness tester was used to measure the coatings hardness. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis were used to investigate the coating microstructure and chemical composition both before and after corrosion. It was found that the modified anodizing, an environmentally friendly coating method, could produce a hard oxide coating with good corrosion protection for the Al–Si alloy.