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采用电荷自洽离散变分Xα方法,对NiTi合金表面生成TiO2氧化层时镍的释放行为进行了理论计算。选取TiO2的主要晶态金红石构型,通过构造合理的团簇模型,计算镍离子在金红石(110)和(100)表面扩散的可能性及其强度大小。对键级、电荷分布,以及态密度的计算结果进行分析显示,当NiTi合金表面形成金红石型TiO2表面膜时,由于镍原子与氧原子之间发生有效的共价成键作用,会抑制表面镍离子的溶出,即从理论上验证了在NiTi合金表面制备金红石型TiO2氧化膜将有利于提高其生物相容性。
The charge-consistent discrete variational Xα method was used to calculate the nickel release behavior of the NiTi alloy surface when TiO2 oxide layer was formed. The main crystalline rutile configuration of TiO2 was selected. By reason of the reasonable cluster model, the possibility of nickel ions diffusion on rutile (110) and (100) surfaces and their strength were calculated. The results of the calculation of bond level, charge distribution and density of states show that when the rutile TiO2 film is formed on the surface of NiTi alloy, the effective covalent bonding between nickel atom and oxygen atom can restrain the surface nickel The dissolution of ions, that is theoretically verified on the NiTi alloy surface preparation of rutile TiO2 oxide film will help to improve its biocompatibility.