Effectiveness Evaluation Study of Self-made Zinc Alloy Sacrificial Anode under Chloride Salt Erosion Environment

Abstract

To investigate the effectiveness of self-made zinc alloy sacrificial anode material for the protection of reinforcement in concrete under chlorine salt erosion environment, salt solution immersion corrosion and electromigration accelerated corrosion tests were used to evaluate the effectiveness of self-made zinc alloy anode with the help of relevant cathodic protection guidelines and evaluation criteria for the corrosion of reinforcement in concrete. The results showed that the protection was effective because the potential of the zinc alloy anode protection steel bar in the salt solution satisfied the “−780 mV (SCE)” validity criterion. The self-corrosion potential (E _corr) of the sacrificial anode protection steel in concrete was greater than −276 mV, and the protective current density of the zinc alloy anode was 1–3 µA·cm⁻², which met the standards of EN12696-2000, further indicating that the self-made zinc alloy sacrificial anode had a good protection combining with the polarization resistance and the appearance of the corroded surface of the steel in concrete. The microscopic morphology of the corroded surface and the composition of the corrosion products indicates that the mortar of the self-made zinc alloy anode has a lower pH than the imported anodes, so the long-term protection of the self-made zinc alloy sacrificial anode needs to be further improved.

Keywords

zinc alloy anode / cathodic protection / steel corrosion / concrete / polarization curve

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