AZ91D镁合金表面扩渗Ce组织及耐蚀性能

Microstructure and corrosion resistance of AZ91D magnesium alloy by cerium surface diffusion

首先采用表面机械研磨的方法实现了AZ91D镁合金表面纳米化,然后研究了熔盐扩渗Ce对AZ91D镁合金表层组织及耐蚀性能影响。采用扫描电镜(SEM)、透射电镜(TEM)以及X射线衍射(XRD)对扩渗层形貌、成分及物相进行了分析,并利用电化学工作站测试了渗层在3.5%Na Cl溶液中的耐蚀性能。研究结果表明,经过表面纳米化及熔盐扩渗Ce后,AZ91D镁合金表面耐蚀能力明显提高,扩渗层厚度随着扩渗时间的延长而增加,扩渗层变得更连续、致密,表面扩渗层的主要富稀土相为Al2Ce金属间化合物。

A surface nano-crystallization layer was prepared on AZ91 D magnesium alloy by surface mechanical attrition treatment（SMAT）and then the cerium diffusion coatings were fabricated by molten salt diffusion method.The morphology,microstructure,composition and phases of the cerium diffusion coatings were characterized by scanning electron microscopy（SEM）,transmission electronic microscopy（TEM） and X-ray diffraction（XRD）.The corrosion resistance of the coatings in 3.5 mass% Na Cl solution was tested on an electrochemical workstation.The results show that the corrosion resistance of the AZ91 D magnesium alloy is obviously improved by the cerium surface diffusion treatment.The thickness of the diffusion coatings increases and its compactness is getting better with the increasing of the diffusion time.The rare earth-enriched phase in the diffusion coatings is Al2 Ce intermetallics.