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以锡酸钠、偏钒酸钠为主盐,通过化学转化处理的方法在AZ91D镁合金表面制备了一种新型Sn-V复合化学转化膜。运用扫描电子显微镜(SEM)及能谱仪(EDS)、X射线衍射(XRD)等测试方法研究了Sn-V复合转化膜的表面形貌与成分组成。结果表明,Sn-V复合化学转化膜由扁圆形颗粒紧密堆积而成,同单一钒酸盐转化膜相比,表面粗糙度增加,裂纹数量减少;复合转化膜膜层厚度为2~3μm,与基体结合良好。电化学测试及浸泡试验结果表明,Sn-V复合转化膜有效的提高了AZ91D镁合金的耐腐蚀性能,且提高幅度明显高于单一钒酸盐转化膜。
A new Sn-V composite chemical conversion coating was prepared on the surface of AZ91D magnesium alloy by chemical conversion treatment with sodium stannate and sodium metavanadate as main salts. The surface morphology and composition of the Sn-V composite film were investigated by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD) The results show that the Sn-V composite chemical conversion film is formed by the compact packing of oblate particles. Compared with the single vanadate conversion coating, the surface roughness increases and the number of cracks decreases. The thickness of the composite conversion coating is 2 ~ 3μm, Good bonding with the substrate. Electrochemical tests and immersion test results show that, Sn-V composite conversion coating effectively improve the corrosion resistance of AZ91D magnesium alloy, and the increase was significantly higher than a single vanadate conversion coating.