Characterization and Effects of Anodized Aluminum Oxide Film on Additively Manufactured AlSi10Mg Alloy

This work investigates the effect of anodized aluminum oxide films on the surface characteristics and corrosion behavior of AlSi10Mg alloy fabricated via laser powder bed fusion (PBF-LB). A ∼10 μm thick oxide layer was formed using sulfuric acid anodizing, under both as-built and stress-relieved (300 °C, 2 h) conditions. Surface morphology, microstructure, and corrosion performance were characterized using scanning electron microscopy, EDS, and immersion testing in 3.5% NaCl solution. Anodizing significantly reduced surface roughness (Ra) from ~14 µm to ~6 µm, with further reduction in extreme topographical features observed in heat-treated samples. Cross-sectional analysis confirmed uniform oxide growth, while immersion tests revealed delayed corrosion onset relative to uncoated material. However, localized pitting was still observed, particularly in heat-treated samples, likely due to Si-network fragmentation. These findings demonstrate that anodizing enhances surface finish and corrosion resistance of AM AlSi10Mg, while microstructural features, such as silicon morphology, remain critical to oxide layer integrity.