Abstract Graphene-oxide/zinc-phosphate composite coatings (GO/ZP) have been synthesized on as-cast Al-Zn (5.0 wt. %)-Mg (2.5 wt.%) alloy substrate using the chemical conversion coatings technique. X-ray diffraction (XRD), electron microscopy (SEM) associated with energy-dispersive X-ray spectroscopy unit (EDX) and X-ray photoelectron spectroscopy (XPS) were utilized for characterizing the microstructure of GO/ZP composite coating films. The electrochemical behavior of GO/ZP composite coatings was studied using potentiodynamic polarization and potentiostatic techniques. The results revealed that the incorporation of GO sheets in the ZP coating bath up to 1.0 g/L led to increasing the coating weight (g/m2) and the corrosion protection efficiency (%). The improvement of corrosion resistance could be attributed to the regular distribution of GO which closed up the free spaces in coating films and inhibited the penetration of corrosive ions into alloy substrate. Nevertheless, a further incorporating of GO (1.25 and 1.5 g/L) gave an adverse effect on the coating weight and the corrosion resistance.

中文翻译：

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氧化石墨烯/磷酸锌复合涂层在铸态 Al-Zn (5.0 wt.%)-Mg (2.5 wt.%) 合金上的制备和电化学行为

摘要 使用化学转化涂层技术在铸态的 Al-Zn (5.0 wt. %)-Mg (2.5 wt.%) 合金基材上合成了氧化石墨烯/磷酸锌复合涂层 (GO/ZP)。X 射线衍射 (XRD)、电子显微镜 (SEM) 与能量色散 X 射线光谱仪 (EDX) 和 X 射线光电子能谱 (XPS) 用于表征 GO/ZP 复合涂层膜的微观结构。使用动电位极化和恒电位技术研究了 GO/ZP 复合涂层的电化学行为。结果表明，在 ZP 镀液中加入高达 1.0 g/L 的 GO 片材导致涂层重量 (g/m2) 和腐蚀保护效率 (%) 的增加。耐腐蚀性能的提高可归因于GO的规则分布，其封闭了涂层膜中的自由空间并抑制了腐蚀性离子渗透到合金基体中。然而，进一步掺入 GO（1.25 和 1.5 g/L）会对涂层重量和耐腐蚀性产生不利影响。