稀土熔盐扩渗对AZ91D镁合金耐蚀性能的影响

发布时间：2018-08-27 13:58

【摘要】：为了提高镁合金的耐蚀性能,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Ce、Nd、Y熔盐扩渗对AZ91D镁合金表层组织及耐蚀性能的影响。采用扫描电镜(SEM)、透射电镜(TEM)以及X射线衍射(XRD)对扩渗层形貌及物相进行了表征,并利用电化学工作站测试了稀土扩渗后合金在3.5%NaCl水溶液中的极化曲线。研究结果表明,经过表面纳米化及熔盐扩渗稀土后,AZ91D镁合金表面形成一层均匀、致密的稀土扩渗层,合金耐蚀能力明显提高,腐蚀电流密度降低一个数量级,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,XRD及TEM结果表明,扩渗层主要由α-Mg,Mg_(17)Al_(12)和富稀土相Al2RE(Ce/Nd/Y)组成。
[Abstract]:In order to improve the corrosion resistance of AZ91D magnesium alloy, surface mechanical grinding method was used to realize the surface nanocrystalline of AZ91D magnesium alloy, and then the effect of Ce,Nd,Y molten salt diffusion on the surface microstructure and corrosion resistance of AZ91D magnesium alloy was studied. Scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD) were used to characterize the morphology and phase of the diffused layer. The polarization curves of rare earth diffused alloy in 3.5%NaCl aqueous solution were measured by electrochemical workstation. The results show that the corrosion resistance of AZ91D magnesium alloy is obviously improved and the corrosion current density is reduced by one order of magnitude after the surface nanocrystalline and molten salt diffusion of rare earth are formed on the surface of AZ91D magnesium alloy. The thickness of the permeable layer increases with the increase of the permeation time, and the permeation layer becomes more continuous. The results of dense XRD and TEM show that the permeation layer is mainly composed of 伪 -Mg _ (17) mg _ (17) Al_ _ (12) and rare earth rich phase Al2RE (Ce/Nd/Y).
【作者单位】：赣南师范大学江西省镁合金材料工程技术研究中心;赣南师范大学化学化工学院;
【基金】：教育部科技重点项目(212093) 江西省高校科技落地计划项目(KJLD13078) 江西省研究生创新基金项目(YC2015-S373)
【分类号】：TG146.22

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