Materials Electrochemistry Laboratory, School of Materials Science and Engineering, Yeungnam University, Gyeongsan, 38541, Republic of Korea.
Sci Rep. 2017 Aug 1;7(1):7063. doi: 10.1038/s41598-017-07691-x.
A novel method to functionalize the surface of inorganic coating by growing organic coating has been investigated based on microstructural interpretation, electrochemical assessment, and quantum chemical analysis. For this purpose, inorganic coating with magnesium aluminate, magnesium oxide, and titanium dioxide was prepared on magnesium alloy via plasma electrolytic oxidation (PEO), and, then, subsequent dip-coating method was used to tailor organic coating using diethyl-5-hydroxyisophthalate (DEIP) as organic molecules. The incorporation of TiO particles worked as a sealing agent to block the micro-defects which resulted mainly from the intense plasma sparks during PEO. In addition, such incorporation played an important role in enhancing the adhesion between inorganic and organic coatings. The use of DEIP as organic corrosion inhibitor resulted in a significant decrease in porosity of inorganic coating. Quantum chemical calculation was used to clarify the corrosion inhibition mechanism which was activated by introduction of DEIP. Thus, the electrochemical analysis based on potentiodynamic polarization and impedance spectroscopy tests in 3.5 wt% NaCl solution suggested that corrosion resistance of magnesium alloy sample was enhanced significantly due to a synergistic effect arising from the hybrid inorganic and organic coatings. This phenomenon was explained in relation to electron transfer behaviour between inorganic and organic coatings.
一种通过在无机涂层表面生长有机涂层来实现功能化的新方法，基于微观结构解释、电化学评估和量子化学分析进行了研究。为此，通过等离子体电解氧化（PEO）在镁合金上制备了含有铝酸镁、氧化镁和二氧化钛的无机涂层，然后采用后续浸涂法使用二乙基-5-羟基间苯二甲酸酯（DEIP）作为有机分子来定制有机涂层。TiO 颗粒的掺入起到了密封剂的作用，可以阻止由于 PEO 期间强烈的等离子体火花而产生的微缺陷。此外，这种掺入在增强无机和有机涂层之间的附着力方面起着重要作用。使用 DEIP 作为有机腐蚀抑制剂导致无机涂层的孔隙率显着降低。量子化学计算用于阐明通过引入 DEIP 激活的腐蚀抑制机制。因此，在 3.5wt%NaCl 溶液中的动电位极化和阻抗谱测试的电化学分析表明，由于混合无机和有机涂层的协同效应，镁合金样品的耐腐蚀性得到了显著提高。这种现象与无机和有机涂层之间的电子转移行为有关。
