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基于密度泛函理论,在广义梯度近似下研究了Cl在γ-TiAl(111)表面的吸附.计算结果表明:γ-TiAl(111)表面的面心立方位置(fcc)和六角密排位置(hcp)为Cl吸附的稳定位置,当覆盖度Θ小于一个单层(ML)时,Cl原子倾向于吸附在γ-TiAl(111)表面近邻为多Ti的位置.电子结构分析发现,Cl原子同表面金属原子形成较强的离子键,并且成键具有一定的方向性.当Cl原子和O原子共同在γ-TiAl(111)表面吸附时,二者都趋于优先占据表面fcc和hcp位置,从而形成吸附竞争;另外,Cl原子的吸附将升高平均每个O原子的吸附能,从而减弱O原子与表面金属原子的结合,这可能是实验中氯化处理能使γ-TiAl抗氧化能力提高的原因之一。
Based on the density functional theory (DFT), the adsorption of Cl on the γ-TiAl (111) surface was investigated by the generalized gradient approximation. The calculated results show that the fcc and γ- hcp) is the stable position of Cl adsorption. When the coverage Θ is less than a single layer (ML), Cl atoms tend to adsorb on the surface of γ-TiAl (111) The surface metal atoms form strong ionic bonds, and the bonding has a certain direction.When both Cl atoms and O atoms are adsorbed on the γ-TiAl (111) surface, both of them tend to occupy preferential positions on the surface fcc and hcp, In addition, the adsorption of Cl atoms will increase the average adsorption energy of each O atom, thereby weakening the combination of O atoms with the surface metal atoms, which may be the experiment of chlorination can make γ-TiAl antioxidant capacity One of the reasons to improve.