Zhao Xia, Wei Jinfei, Li Bucheng, Li Sibei, Tian Ning, Jing Lingyun, Zhang Junping
Department of Chemical Engineering, College of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou 730050, PR China.
Department of Chemical Engineering, College of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou 730050, PR China; Center of Eco-Material and Green Chemistry, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 730000 Lanzhou, PR China.
J Colloid Interface Sci. 2020 Sep 1;575:140-149. doi: 10.1016/j.jcis.2020.04.097. Epub 2020 Apr 24.
Magnesium alloys have many excellent properties, but the poor corrosion resistance seriously hinders their widespread applications. Here, we report a self-healing superamphiphobic coating for efficient corrosion protection of magnesium alloy by the combination of a compact self-healing epoxy resin (SHEP) coating and a porous superamphiphobic coating. The coating shows (i) excellent superamphiphobicity with high contact angle, low sliding angle and robust impact/bounce behavior, (ii) excellent anti-corrosion performance as demonstrated by the potentiodynamic polarization curves and electrochemical impedance spectroscopy, and (iii) excellent self-healing performance as proved by the scanning electron microscopy and electrochemical impedance spectroscopy. This is owing to synergistic effect of the bi-layer structure. Furthermore, the healed coating retained excellent anti-corrosion performance according to the immersion test and neutral salt spray test. This is because the SHEP layer can effectively drive repair of microstructure of the superamphiphobic layer, and then recover of superamphiphobicity. Therefore, the contact area and contact time of corrosive solutions with the pristine and healed coatings are limited, which efficiently prevents diffusion of corrosive substances such as water, chloride ions and oxygen. The self-healing superamphiphobic coating may find applications in protection of various metal alloys.
镁合金具有许多优异的性能，但其耐腐蚀性较差严重阻碍了它们的广泛应用。在此，我们报道了一种通过致密的自愈合环氧树脂（SHEP）涂层与多孔超疏水涂层相结合的用于镁合金高效腐蚀防护的自愈合超疏水涂层。该涂层表现出：（i）具有高接触角、低滑动角和稳健的冲击/反弹行为的优异超疏水性；（ii）动电位极化曲线和电化学阻抗谱所表明的优异耐腐蚀性能；（iii）扫描电子显微镜和电化学阻抗谱所证明的优异自愈合性能。这归因于双层结构的协同效应。此外，根据浸泡试验和中性盐雾试验，愈合后的涂层保持了优异的耐腐蚀性能。这是因为SHEP层能够有效地驱动超疏水层微观结构的修复，进而恢复超疏水性。因此，腐蚀性溶液与原始涂层和愈合涂层的接触面积和接触时间受到限制，这有效地防止了水、氯离子和氧气等腐蚀性物质的扩散。这种自愈合超疏水涂层可能在各种金属合金的防护中找到应用。
