镁合金表面黄色锆盐转化膜的性能

Properties of yellow zirconium-based conversion coating on magnesium alloy

室温条件下采用含K_2ZrF_6 1.75g/L、MgSO_4 1.00g/L、NaF 1.25g/L、着色剂1.0g/L和稳定剂0.25g/L的溶液,在镁合金表面制备了黄色的锆盐转化膜。采用极化曲线、电化学阻抗谱和点滴腐蚀试验研究了锆盐转化膜的耐蚀性,利用扫描电镜(SEM)、能谱(EDS)和X射线光电子能谱(XPS)分析了它的表面形貌、成分与结构。结果表明:锆盐转化膜为网状结构,裂纹均匀,主要由Mg、Zr、O、F、C等元素组成,能使镁合金的耐腐蚀性得到显著提升。

A yellow Zr-based conversion coating was prepared on the surface of magnesium alloy from a bath composed of K2ZrF6 1.75 g/L, MgSO4 1.00 g/L, NaF 1.25 g/L, coloring agent 1.0 g/L and stabilizing agent 0.25 g/L. The corrosion resistance of the Zr-based conversion coating was studied by polarization curve measurement, electrochemical impedance spectroscopy and dropping corrosion test. The surface morphology, composition and structure of the Zr-based conversion coating were analyzed by scanning electron microscopy （SEM）, energy-dispersive spectroscopy （EDS） and X-ray photoelectron spectroscopy （XPS）. The results showed that the Zr-based conversion coating presents a network structure with uniform distribution of cracks, mainly composed of Mg, Zr, O, F, C and other elements, and greatly improves the corrosion resistance of magnesium alloy substrate.