Anticorrosion study of phytic acid ligand binding with exceptional self-sealing functionality

Abstract

Self-sealing functionality has attracted significant interest over the past few decades because it can generously extend the alloy corrosion protection ability. Faced with this trend of anti-corrosion, we fabricated a smart composite ceramic coating on magnesium-lithium (Mg–Li) alloys. Meanwhile, the composite coating was fabricated by incorporating a coupling agent (phytic acid) between the micro-arc oxidation (MAO) film and stannate coating to improve the coverage of the conversion coating. The corrosion behavior in simulated seawater was examined by electrochemical impedance spectroscopy. Surface structure and composition were characterized by scanning electron microscopy (SEM). X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Results revealed that the composite coating displayed an excellent enhancement in corrosion resistance and outstanding long-term anticorrosion performance due to the self-sealing feature. Moreover, self-sealing performance of stannate conversion coating was described by the theory of dissolution-reprecipitation, which is the process of an old phase dissolving and new phase generating, and the new phase is deposited on the surface of the sample. These results suggested that the advantages of the prepared composite coating have a great value in the practical application.