Performance Optimization of Al-Zn-In-Sn-Mg Al-Based Sacrificial Anodes in Oilfield Produced Water Environments with CCUS Technologies

To address activation and durability of Al-based sacrificial anodes in CCUS weakly acidic chloride-rich environments, this study investigated electrochemical performance and corrosion behavior of Al-Zn-In-Sn-Mg alloys. Using 1060 industrial aluminum, six alloy groups with varying Zn, Mg, In, and Sn contents were designed, characterized via microstructure analysis, electrochemical tests, current efficiency measurements, and 3D surface characterization. Alloy 6# exhibited optimal performance with uniformly distributed secondary phases (Zn-rich particles, Mg-Zn intermetallics, In-Sn activation phases) and refined dendrites. It demonstrated corrosion potential of -1.129V(SCE), corrosion current density of 2.64×10-6 A·cm-2, current efficiency of 92.13%, and theoretical capacity of 2882.98 A·h/kg, with uniform corrosion morphology and no surface product adhesion. Superior performance resulted from Zn-Mg-In-Sn synergy: high Zn/Mg enhanced activation and matrix strengthening, while balanced In/Sn promoted uniform dissolution. The corrosion process involved three stages: secondary phase dissolution, pit initiation/propagation, and transition to uniform corrosion. Optimizing Zn/Mg contents and In/Sn ratio significantly improved current efficiency and stability, providing theoretical/experimental foundations for high-performance Al-based sacrificial anodes in CCUS weakly acidic environments.