Abstract

In order to enhance the corrosion resistance of molybdate conversion coating, the molybdate coating is subjected to micro-arc oxidation treatment in electrolyte with Na₂SiO₃ as a main salt. The electrochemical behavior and corrosion weight loss of different coating were studied. The surface morphology, element composition, roughness and phase composition of different coatings were analyzed by SEM, EDS, laser confocal microscopy and XRD, the growth process of different micro-arc oxidation coatings was explored. The results shows that the arcing voltage of the molybdate coating enhanced by micro-arc oxidation is significantly reduced, the corrosion potential is shifted to the right, and the corrosion weightlessloss of the coating is the lowest, compared with the molybdate coating and the micro-arc oxidation coating. Micro-arc oxidation on the surface of the molybdate coating is beneficial to the formation of MgAl₂O₄ and the production of new phase is MoSi₂, which can better improve the corrosion resistance of the molybdate coating. The micro-arc oxide coating does not form a ceramic film with a pore structure at the moment of arcing. As the micro-arc oxidation time prolongs, the ceramic film is gradually formed. When the time reaches 60 s, the ceramic film is completely formed.

Graphic Abstract

In this paper, micro-arc oxidation treatment is performed on the basis of molybdate conversion coating to obtain micro-arc oxidation enhanced molybdate coating. The experiment is mainly divided into three parts: the first part, molybdate conversion treatment of the magnesium alloy substrate to obtain a molybdate conversion coating. The second part, the micro-arc oxidation treatment is performed on the surface of the molybdate coating, and discharge channels appear on the surface. The third part, micro-arc oxidation enhanced molybdate coating is obtained.

中文翻译：

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微弧氧化增强镁合金钼酸盐转化涂层的影响

摘要

为提高钼酸盐转化膜的耐腐蚀性能，钼酸盐涂层在含Na ₂ SiO _{3 的}电解液中进行微弧氧化处理作为主盐。研究了不同涂层的电化学行为和腐蚀失重。通过SEM、EDS、激光共聚焦显微镜和XRD分析了不同涂层的表面形貌、元素组成、粗糙度和相组成，探索了不同微弧氧化涂层的生长过程。结果表明，微弧氧化增强的钼酸盐涂层的电弧电压显着降低，腐蚀电位向右移动，涂层的腐蚀失重与钼酸盐涂层和微弧氧化相比最低。电弧氧化涂层。钼酸盐涂层表面的微弧氧化有利于MgAl ₂ O ₄的形成，产生新相MoSi₂、能更好地提高钼酸盐涂层的耐腐蚀性能。微弧氧化涂层在飞弧瞬间不形成具有孔隙结构的陶瓷膜。随着微弧氧化时间的延长，陶瓷膜逐渐形成。当时间达到60s时，陶瓷膜完全形成。

图形摘要

本文在钼酸盐转化涂层的基础上进行微弧氧化处理，获得微弧氧化增强钼酸盐涂层。实验主要分为三部分：第一部分，对镁合金基体进行钼酸盐转化处理，得到钼酸盐转化涂层。第二部分，钼酸盐涂层表面进行微弧氧化处理，表面出现放电通道。第三部分，获得微弧氧化增强钼酸盐涂层。