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.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
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
关键词
Γ-TIAL
第一性原理
氧化
吸附能
表面能
化学势
γ-TiAl, first-principles, oxidation, adsorption energy, surface energy, chemical potential
