Anticorrosion performance of acriflavine–Zn2+ system for mild steel in seawater utilization

An organic/inorganic hybrid corrosion inhibitor based on acriflavine/zinc acetate in controlling corrosion of mild steel in natural seawater was studied through electrochemical techniques, scanning electron microscopy (SEM-EDX), X-ray photoelectron spectroscopy (XPS) and quantum chemical calculations. The experimental results demonstrated the incorporation of acriflavine and Zn2+ significantly improve the uniformity and corrosion resistance of the protective film, and showed a synergistic inhibition effect. Electrochemical measurements indicated the acriflavine acts as a mixed-type inhibitor, and the acriflavine-Zn2+ complex acts as an anodic inhibitor. The optimal mass ratio of acriflavine to Zn2+ was found to be 1:1 in view of the inhibition efficiency of polarization curves. Surface analysis verified the formation and characteristic of acriflavine-Zn2+ film on steel surface. The complex film was mainly composed of Zn(OH)2, [Fe(III), Zn(II)–AF] and oxides/hydroxides of iron(III) based on XPS analysis.