NiTi合金表面TiO_2掺杂C原子的电子结构计算

Study on the surface electronic structure of doped C NiTi alloy

采用基于密度泛函理论的离散变分Xα方法(DV—Xα),对表面掺杂C原子后的NiTi合金表面Ti0_2的电子结构进行了计算,得到各原子间的键级、电荷分布、Mulliken集居数和态密度．结果表明:表面掺杂C后,在Ti原子的3d、4s、4p轨道和C原子的2p轨道之间发生了有效的作用,改变了表面膜的电荷分布,表面负电荷增加,从而抑制了CI-等阴离子的吸附,阻碍电子的失去,提高了其抗点蚀的能力;同时,也有利于体液中ca2+、PO34在表面沉积形成羟基磷灰石,使NiTi合金的耐腐蚀性得到进一步提高．这一理论计算阐明了NiTi合金表面掺C后抗腐蚀性和生物相容性提高的机制．

The discrete variational Xα method （DV-Xα） within the framework of density-functional theory was used to study the surface electronic structure of doped C NiTi alloy. The bond order and charge distribution was calculated. Mulliken population and partial density of state analysis showed that Ti atom and doped C atom interacted by the 2p （N） electrons and the 3d, 4s, 4p （Ti） electrons, thus causing a renewed distribution of charge within the titanium dioxide surface, and in fact increasing the surface negative charge. The result provided a theorctic interpretation for the improvement of the biocompatibility and corrosion resistance of doped C NiTi alloy.