Synergistic Inhibition Effect of Zinc Acetylacetonate and Benzothiazole in Epoxy Coating on the Corrosion of Mild Steel

The corrosion inhibition effect of zinc acetylacetonate (ZAA) and benzothiazole (BTH) mixture was evaluated for mild steel in 3.5% NaCl solution. To this end, ZAA: BTH mixtures ranged from 6: 1 to 1: 6 mol ratios were examined by weight loss and open circuit potential to obtain optimal mole ratio. The optimal mixture of ZAA: BTH at 1: 5 mol ratio showed a significant corrosion inhibition efficiency proved by electrochemical impedance spectroscopy and polarization studies. The addition of the optimal mixture of ZAA: BTH to epoxy coating showed a considerable increase of corrosion protection evaluated by salt spray exposure.