Mg_2Ge合金表面性质的第一性原理计算  

First Principles Calculations of the Surface Properties of Mg_2Ge Alloy

作　　者：罗哲 朱虹[2] 应韬 曾小勤[1] LUO Zhe;ZHU Hong;YING Tao;ZENG Xiaoqin(School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240, China)

机构地区：[1]上海交通大学材料科学与工程学院,上海200240 [2]上海交通大学上海交通大学密西根学院,上海200240

出　　处：《铸造技术》2018年第6期1359-1363,共5页Foundry Technology

基　　金：国家自然科学基金(51601111);中国博士后科学基金(2016M601590)

摘　　要：镁锗合金有着良好的耐腐蚀性能,与其表面性质有着密切关系,但具体机制不明确。因此,基于电子密度泛函理论,计算了Mg_2Ge(100),(110),(111)面的表面能和电子亲合能。结果表明,Mg_2Ge最稳定的表面为(111)中的一种,其表面原子全由镁构成,第二层原子由锗原子构成,与实验报道Mg_2Ge的解离面为(111)面吻合。不同表面构型的电子亲合能差异很大,说明Mg_2Ge的腐蚀行为如腐蚀电位等应存在较强的各向异性。在理想界面中,镁的费米能级位于Mg_2Ge的导带底的下方,形成的肖特基能垒会阻碍电子由镁基体转移到Mg_2Ge,从而使镁锗合金表现出更好的耐腐蚀性能。Mg-Ge alloy had good corrosion resistance and are closely related to their surface properties, but the specific mechanism was not clear. Therefore, based on electron density functional theory, the surface energy and electron affinity of （100）, （110） and （111） surfaces of Mg2Ge alloy can be calculated. The results show that the most stable surface of Mg2Ge is （111）, the surface atom is composed of magnesium, while the second layer atoms are composed of germanium atom, and the dissociative side of Mg2Ge （111） is consistent with the experiment. The electron affinity of different surface configurations can be very different, it indicates that the corrosion behavior of Mg2Ge should have strong anisotropy, such as corrosion potential. With ideal interface assumption, the Fermi level of Mg locates below the conductive band minimum of Mg2Ge, which will lead to Schottkey barrier prevents electronic from Mg matrix to MgzGe and improve the corrosion resistance of Mg2Ge alloy.

关 键 词：Mg2Ge 第一性原理计算 表面能 电子亲合能 腐蚀 

分 类 号：TG146.2[一般工业技术—材料科学与工程]