Corrosion behavior of AlSi10Mg alloy produced by laser powder bed fusion under chloride exposure

Potentiodynamic tests were performed on AlSi10Mg alloy produced using laser powder bed fusion. As corrosion depends on the surface conditions, we compared the rough as-built surface with that formed after mechanical polishing and passivation in air. The as-built samples showed lower pitting potentials than polished samples. Corrosion initiation depended heavily on the chloride concentration. The higher potential of Si particles compared to the Al matrix provided the driving force for selective dissolution of the alpha-Al phase. The potential difference between the Si particles and alpha-Al phase was higher at the melt pool edges, resulting in preferential attack of these regions.