The cerium salt chemical conversion baths containing KMnO₄ are applied to prepare protective coatings on the WA42 alloy surface, and the effect of the concentration of KMnO₄ on the microstructure and corrosion properties of the coatings is investigated by scanning electron microscopy, X‐ray photoelectron spectroscopy, and electrochemical tests. The results indicate that with the addition of KMnO₄ to the conversion bath, the microstructure of the coating is more uniform and denser, and the coating with the KMnO₄ concentration of 4 g/L (4M coating) has the most uniform microstructure with the least microcracks. The 4M coating exhibits a two‐layered structure, and it is mainly composed of MgO, Mg(OH)₂, CeO₂, Ce₂O₃, Ce(OH)₃, MnO, and MnO₂. In addition, as the KMnO₄ concentration increases from 0 to 6 g/L, the I_corr of the coatings in 3.5% NaCl solution decreases first and then increases, and the 4M coating shows the best corrosion resistance, which should attribute to the uniform and dense microstructure.

中文翻译：

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基于Mg–4Y–2Al镁合金的具有优异耐腐蚀性的铈基转化膜的设计

将含有KMnO ₄的铈盐化学转化浴用于在WA42合金表面上制备保护涂层，并通过扫描电子显微镜，X射线光电子学研究了KMnO ₄的浓度对涂层的组织和腐蚀性能的影响。光谱学和电化学测试。结果表明，在转化浴中加入KMnO ₄后，涂层的微观结构更加均匀致密，KMnO ₄浓度为4 g / L的涂层（4M涂层）的显微组织最均匀。最少的微裂纹。4M涂层具有两层结构，主要由MgO，Mg（OH）₂，CeO组成₂，Ce ₂ O ₃，Ce（OH）₃，MnO和MnO ₂。另外，随着KMnO ₄浓度从0增加到6 g / L，在3.5％NaCl溶液中涂层的I _corr先降低然后升高，并且4M涂层显示出最佳的耐腐蚀性，这应归因于均匀和致密的微观结构。