Al3V表面氧吸附的第一性原理研究  

First-Principles Study on the Adsorption of Oxygen on Al3V Surfaces

作　　者：高翔 张桂凯[2] 向鑫[2] 罗丽珠[1] 汪小琳[3] Gao Xiang;Zhang Guikai;Xiang Xin;Luo Lizhu;Wang Xiaolin(Science and Technology on Surface Physics and Chemistry Laboratory,Jiangyou 621908,China;Institute of Materials,China Academy of Engineering Physics,Jiangyou 621907,China;China Academy of Engineering Physics,Mianyang 621900,China)

机构地区：[1]表面物理与化学重点实验室,四川江油621908 [2]中国工程物理研究院材料研究所,四川江油621907 [3]中国工程物理研究院,四川绵阳621900

出　　处：《稀有金属材料与工程》2020年第12期4185-4191,共7页Rare Metal Materials and Engineering

基　　金：国家磁约束核聚变能发展研究专项(2017YFE0300304,2018YFE0313100);国家自然科学基金(11975213)。

摘　　要：采用基于密度泛函理论的第一性原理方法,计算了低指数Al3V表面的表面能,分析其稳定性;然后采用最稳定表面研究了Al3V表面的O吸附行为以及合金元素的影响。结果表明,终止于Al原子的(110)面是最稳定的表面。O原子倾向于吸附在(2×1)-(110)-Al表面桥位,且随着覆盖度增加,O吸附的稳定性增加。从态密度(density of states,DOS)分析和O与表面各原子的间距可以推断,该表面在氧化的初始阶段发生Al的氧化和V的内氧化,氧化后有可能形成具有保护性的Al2O3膜。合金元素Ti和Cr均倾向于占据表面第2层V原子位,且都促进O原子在表面的吸附,但二者的作用机制不同,Ti与O相互作用较强,从而降低了Al与O的相互作用,在氧化过程中Ti与Al有可能同时氧化,从而形成Al和Ti的混合氧化物;Cr对于Al和O的相互作用有微弱的增强作用,使得O的吸附更加稳定,可能会促进Al的氧化,从而形成保护性的Al2O3。Based on the density-functional theory,the stability of low-index surfaces of Al3V intermetallic was analyzed by first-principles calculations.The adsorption of oxygen on Al3V surface and the effects of alloying elements were studied with the most stable surface.The results show that Al-terminated(110)surface is the most stable surface.The adsorption of oxygen prefers to occur at bridge sites of the surface,and it becomes more stable when the coverage increases.It can be inferred from the density of states(DOS)analysis and the distance between O and other atoms that at the initial stage,the oxidation of Al atoms and internal-oxidation of V atoms occur,suggesting the protective Al2O3 scale can be formed after oxidation.Ti and Cr atoms prefer to substitute V atoms in the 2 nd layer.The substitution of the atoms can improve the adsorption stability of oxygen on the surface,while their mechanisms are different.On the one hand,interactions between Ti and O atoms are strong,so the interactions between Al and O atoms are wea kened after Ti substitution occurs,which means both Ti and Al can be oxidized to form mixed oxides.On the other hand,Cr substitution slightly enhance s the interactions between Al and O atoms,which makes the O adsorption more stable;as a result,the oxidation degree of Al atoms may improve,and thus the protective Al2O3 scale can be formed.

关 键 词：第一性原理 Al3V表面 氧吸附 

分 类 号：TL341[核科学技术—核技术及应用] O647.3[理学—物理化学]