氧原子在γ-TiAl(111)表面吸附的第一性原理研究  

FIRST-PRINCIPLES STUDY OF OXYGEN ATOM ADSORPTION ONγ-TiAI(111)SURFACE

作　　者：李虹[1] 刘利民[1] 王绍青[1] 叶恒强[1] 

机构地区：[1]中国科学院金属研究所沈阳材料科学国家(联合)实验室,沈阳110016

出　　处：《金属学报》2006年第9期897-902,共6页Acta Metallurgica Sinica

基　　金：国家重点基础研究发展规划资助项目G2000067104

摘　　要：运用第一性原理方法对氧原子在γ-TiAl(111)表面的吸附研究表明,氧原子倾向于吸附在近邻表面层多Ti的位置,随着覆盖率的增加,表面不同位置吸附能差别减小．电子结构分析发现,氧原子同表面金属原子形成以离子特性为主的化学吸附．氧化学势对TiAl表面稳定性影响的研究表明,γ-TiAl(111)清洁表面只能在氧化学势很低时可以稳定存在,氧化学势稍高,清洁表面就变得不稳定,氧原子开始吸附,并迅速达到高覆盖率的情况．Oxygen atom adsorption on γ-TiAl（lll） surface is studied using first-principles approach. The adsorption site with more Ti atoms as its nearest neighbors on the surface layer is found to be preferred. Adsorption energy differences between different adsorption sites become smaller with increasing of oxygen coverage. Electron structure analysis shows the chemisorption is characterized mainly by ionic bonds. The stability of γ-TiAl（111） surfaces are investigated in a range of oxygen chemical potential, which indicated that the clean surface can be energetically stable only when the oxygen chemical potential is very low. For higher oxygen chemical potential the clean surface becomes unstable, therefore, the oxygen atoms start to adsorb on it, and soon come up to high coverage.

关 键 词：Γ-TIAL 第一性原理 氧化 吸附能 表面能 化学势 

分 类 号：TG132.32[一般工业技术—材料科学与工程]