Excellent performance of dodecyl dimethyl betaine and calcium gluconate as hybrid corrosion inhibitors for Al alloy in alkaline solution

Dodecyl dimethyl betaine (BS-12) and calcium gluconate (CaGlu) are examined as hybrid corrosion inhibitors for AA5052 aluminum alloy in 4 M NaOH electrolyte. The corrosion inhibition is investigated by hydrogen evolution tests, electrochemical measurements, surface analysis, and theoretical calculation. It demonstrates that the hybrid inhibitors can protect aluminum alloy effectively. CaGlu has a good coordination effect with aluminum ions. The hydrophilic group of BS-12 can occupy the active sites on the aluminum alloy/solution interface. The hydrophobic alkyl chain can further enhance the corrosion inhibition effect. The maximum corrosion inhibition efficiency reaches 86.3% at 1 mM BS-12 + 3 mM CaGlu.