AZ31镁合金钕基转化膜研究

Investigation of neodymium-based conversion coating on AZ31 magnesium alloy

摘要:

通过化学转化成膜在AZ31镁合金表面制备了钕基转化膜。利用称重实验和OCP测试研究了钕基转化膜的成膜过程，利用SEM，EDS和XPS分别研究了膜层形貌，微观结构和组成成分。研究了空白样品与镀膜样品在3.5 wt.% NaCl 溶液中浸泡不同时间后样品表面形貌和成分，结果表明钕基转化膜可以有效的降低AZ31镁合金在NaCl溶液中的腐蚀速率。利用XRD和电化学测试研究了经过后处理以后的钕基转化膜的成分和耐蚀性能，结果说明后处理可以进一步改善钕基转化膜的腐蚀性能。

Abstract:

The neodymium –based (Nd-based) conversion coating was obtained on the surface of AZ31 magnesium alloy. The formation process of Nd-based conversion coating was examined by weighting experiment and open cruit potential (OCP) test. The coating morphology, micro-structure and composition were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy(XPS) and X-ray diffraction (XRD)，respectively. The variation of morphology between bare sample and coated sample immersed in 3.5 wt.% NaCl aqueous solution was investigated, the results showed that the Nd-based conversion coating can effectively reduce the corrosion speed in 3.5 wt.% NaCl aqueous solution. The composition and corrosion resistance of post-treatment on Nd-based conversion coating were measured by XRD and electrochemical experiments. The post-treatment can perfectly improve the corrosion resistance of the Nd-based conversion coating.