稀土元素Ce、Y在Mg-Mn-RE镁合金腐蚀中的作用及其差异  

Effects and Difference of Ce and Y on Corrosion Behaviors of Mg-Mn-RE Magnesium Alloys

作　　者：王熠玮 郭锋[1,2] 胡文鑫 刘亮[1,2] 赵学平[1,2] WANG Yi-wei;GUO Feng;HU Wen-xin;LIU Liang;ZHAO Xue-ping(School of Material Science and Engineering,Inner Mongolia University of Technology,Hohhot 010051,China;Inner Mongolia Key Laboratory of Thin Film and Coatings,Hohhot 010051,China;Baotou Research Institute of Rare Earths,Inner Mongolia Baotou 014030,China)

机构地区：[1]内蒙古工业大学材料科学与工程学院,呼和浩特010051 [2]内蒙古自治区薄膜与涂层重点实验室,呼和浩特010051 [3]包头稀土研究院,内蒙古包头014030

出　　处：《表面技术》2023年第9期232-240,264,共10页Surface Technology

基　　金：内蒙古自治区科技项目(2020GG0318)。

摘　　要：目的探究Ce、Y稀土元素在Mg-Mn-RE镁合金腐蚀中的作用及其差异。方法制备不同稀土含量的Mg-Mn-Ce和Mg-Mn-Y合金,采用在NaCl溶液中浸泡的方法,考察合金的腐蚀性能及腐蚀类型。测试合金的电化学性质,分析合金的腐蚀与缓蚀机制。基于合金显微组织的变化,讨论Ce、Y元素在合金腐蚀中的作用及其差异。结果Mg-Mn-Ce和Mg-Mn-Y合金的腐蚀率随浸泡时间的增加而减小。当Ce、Y的质量分数分别为1.0%和0.5%时,合金的腐蚀质量损失最小。Mg-Mn-Ce合金中的Ce几乎全部形成了Mg_(12)Ce化合物,并以共晶体的形式分布于晶界,合金优先在晶界发生微电偶腐蚀,表现出典型的晶间腐蚀形貌。随着Ce含量的提高,Mg-Mn-Ce合金的微电偶腐蚀加剧。Mg-Mn-Y合金以基体的阳极溶解为主,基体从固溶应力较大的腐蚀活性点优先开始腐蚀,合金表现出带有微坑的均匀腐蚀形貌。随着Y含量的提高,Mg-Mn-Y合金的阳极溶解腐蚀加快。Ce、Y元素能提高合金的膜电阻和电荷转移电阻,但Ce和Y分别在提高膜电阻和电荷转移电阻方面具有更明显的作用,且分别通过提高腐蚀产物膜的致密性和固溶体的电位对合金的腐蚀产生减缓作用。结论Mg-Mn-Ce和Mg-Mn-Y合金的显微组织以及Ce、Y在合金腐蚀中的作用不同,导致合金的腐蚀和缓蚀机制存在明显的差别。To explore the effects and differences of Ce and Y rare earth elements on corrosion performance of Mg-Mn-RE magnesium alloys,the Mg-Mn-Ce and Mg-Mn-Y alloys with Ce and Y contents of 0.5,1.0,1.5 and 2.0 wt.%were prepared and the corrosion performance and corrosion type of the alloys were investigated by immersion corrosion test in 3.5%NaCl solution.The mechanisms of corrosion and corrosion inhibition of the alloys were analyzed by measuring their electrochemical polarization curve,AC impedance spectrum and micro-area potential distribution.Further,the effects of Ce and Y elements on the corrosion of alloys and their differences were discussed based on the change of microstructure of the alloys.The results indicated that the corrosion rate of Mg-Mn-Ce and Mg-Mn-Y alloys decreased with the increase of immersion time.When the contents of Ce and Y were 1.0 wt.%and 0.5 wt.%respectively,the corrosion weight loss after immersion for 1 day and average daily corrosion weight loss for 7 days of the alloys were the smallest.Almost all Ce in Mg-Mn-Ce alloy formed Mg_(12)Ce compound and distributed in grain boundary in the form of eutectics.The potential of the compound was lower than that ofα-Mg phase,which could form the galvanic cell with theα-Mg phase.As a result,micro-galvanic corrosion occurred preferentially in grain boundary and Mg-Mn-Ce alloy showed a typical intergranular corrosion type.With the increase of Ce content in Mg-Mn-Ce alloy,the amount of compound increased,and the degree of intergranular corrosion was aggravated accordingly.Mg-Mn-Y alloy was mainly dominated by the anodic dissolution of matrix.However,Y in Mg-Mn-Y alloy mainly dissolved inα-Mg phase and caused stress inα-Mg solid solution and the corrosion of matrix began preferentially at the active points of corrosion with higher stress.Mg-Mn-Y alloy showed a type of uniform corrosion with micro pits.With the increase of Y content in the alloy,the density of active point caused by stress increased,and the corrosion rate of the matrix became faster.

关 键 词：Mg-Mn-RE镁合金 稀土Ce和Y 显微组织 腐蚀性能 腐蚀类型 腐蚀与缓蚀机制 

分 类 号：TG172.5[金属学及工艺—金属表面处理]