A trivalent chromium conversion coating formed in an Fe(II)-containing solution on AA2024 alloy has been investigated by high resolution analytical electron microscopy, ion beam analysis, Raman spectroscopy and electrochemical tests. It is shown that preferential oxidation of Fe(II) species by H₂O₂ at cathodic sites on the alloy surface suppresses the oxidation of Cr(III) species, hence reducing the Cr(VI) content of the coating. The addition of Fe(II) species has only minor influences on the general composition of the coating, the kinetics of coating growth and the corrosion protection of the alloy.

中文翻译：

---

Fe（II）修饰的三价铬转化工艺对AA 2024合金涂层过程中Cr（VI）形成的影响

已经通过高分辨率分析电子显微镜，离子束分析，拉曼光谱和电化学测试研究了在Aa2024合金上的含Fe（II）溶液中形成的三价铬转化膜。结果表明，H ₂ O ₂在合金表面的阴极部位优先氧化Fe（II）物种，从而抑制了Cr（III）物种的氧化，从而降低了涂层中Cr（VI）的含量。Fe（II）种类的添加对涂层的一般组成，涂层生长动力学和合金的腐蚀防护影响很小。