金属Al、Cu钝化机理电子理论研究

通过计算机编程建立水吸附Al和Cu的模型,利用实空间的Recussion方法分别计算了Al和Cu被H2O吸附前后系统的状态密度和能量变化,及表面金属原子与其近邻原子间的键级积分,并将两个计算结果进行比较.从结果中分析,金属原子的电子转移到H2O分子的O原子上.水吸附金属表面后,状态密度有所下降,次表面原子几乎不受影响,系统总能降低,系统变稳定.H2O使金属表面化学活性降低,并从键级积分计算结果中讨论了Al和Cu钝化膜的形成机理:水通过氧与金属表面原子成键后,表面金属原子与次表面原子作用增强,水中氧和氢原子相互作用改变的不同导致形成不同的钝化膜.

Electronic Theory on Passivasion Mechanism of Al and Cu Metal

Model for adsorption of H2O on Al and Cu were set up with computer programming. TDOS, LDOS, energy change of Al and Cu before and after absorption of H2O, and total bond order integral between metal and neighbor were calculated by using recursion method, then resuhs of these two calculations were compared. Calculation results show that electron of surfer metal atom transfer to O atom of H2O, density of states decreased, atoms under surface were hardly affected, energy of system decent, and the whole system became stable after H2O adsorption. Chemical activity of surface metal was dropped. Mechanism of passivation film of Al and Cu were discussed from the total bond order integral results. After H2O through O band with surfer metal atom, interaction between surface atom and primary surface atoms enhanced. The change of interaction between O and H resuhed in different formation of passive state films.