镧铈混合稀土对AM60B镁合金电化学行为的影响  

Effect of Lanthanum-Cerium Mixed Rare Earth on Electrochemical Behavior of AM60B Magnesium Alloy

作　　者：黄乃宝[1] 邱忠瑜 任婧[1] 梁成浩[1] 

机构地区：[1]大连海事大学材料科学与工程系,辽宁 大连

出　　处：《材料科学》2019年第10期923-933,共11页Material Sciences

基　　金：国家自然科学基金项目(21676040, 21276036),科技部重点研发计划(2016YFB0101206),大连市创新基金项目(2018J12GX053)。

摘　　要：本文采用析氢实验、Mott-Schottky分析和电化学测试技术研究了3.5% NaCl溶液中La、Ce混合稀土对AM60B镁合金电化学性能的影响,并探讨其作用机理。结果表明,AM60B镁合金的析氢腐蚀电流密度降低、腐蚀电位升高、腐蚀电流密度降低、容抗弧值增大、电荷反应电阻Rct增大、双电层电容Cdl降低,镁合金的电化学性能提高,其原因归结于添加的La、Ce混合稀土元素细化了α-Mg晶粒、减弱了β相的电偶腐蚀作用,加之镁合金表面形成致密的La2O3和CeO2复合氧化膜,有效地阻隔Cl?向镁合金表面渗入,抑制了镁合金的溶解。Mott-Schottky曲线测试结果表明,少量添加La、Ce混合稀土AM60B镁合金在?1.9 V~?1.0 V的电位区间曲线呈线性,呈n-型半导体特征,供体密度ND减小,平带电位EFB负向移动,添加稀土La、Ce的镁合金耐蚀性得到提高。The effect of La, Ce mixed rare earth in 3.5% NaCl solution on the electrochemical properties of AM60B magnesium alloy was studied by hydrogen evolution experiment, Mott-Schottky analysis and electrochemical test, and its mechanism was discussed. The results show that the hydrogen evolution corrosion current density of AM60B magnesium alloy decreases;the corrosion potential increases;the corrosion current density decreases;the capacitance arc value increases;the charge reaction resistance Rct increases;and the double layer capacitance Cdl decreases, which improves the electrochemical properties of magnesium alloy, which is due to the addition of La, Ce mixed rare earth elements to refine α-Mg grain and weaken the galvanic corrosion of β phase. The occasional corrosion, coupled with the formation of dense La2O3 and CeO2 composite oxide films on the surface of magnesium alloy, effectively blocks the infiltration of Cl? into the surface of magnesium alloy and suppresses the dissolution of magnesium alloy. The results of Mott-Schottky curve show that the potential range curve of a small amount of La, Ce mixed rare earth AM60B magnesium alloy is linear in the range of ?1.9V - ?1.0V, showing n-type semiconductor characteristics;the donor density ND decreases and the flat band potential EFB moves negatively. The corrosion resistance of magnesium alloy with rare earth La, Ce was improved.

关 键 词：镁合金 镧铈混合稀土 析氢反应 电化学行为 Mott-Schottky分析 

分 类 号：TG1[金属学及工艺—金属学]