镍基合金腐蚀极化曲线的量子力学解释

Interpretation of the Polarization Curve of Alloy 690 by Quantum Mechanics

摘要:

镍基合金Alloy 690广泛应用于高温换热管道中，对其腐蚀机理的准确分析可以为设备提供有效的防腐手段。针对腐蚀表面金属氧化膜具有半导体的性质，利用量子力学的相关知识获得在不同电位下腐蚀过程所对应的能带结构图，分析了产生电流的机理和特点；并从理论上推导出了腐蚀过程中腐蚀电位与电流的相互关系；从微观上解释了腐蚀的动力学机理。结果显示：Alloy 690的腐蚀过程实际上是一种电子的转移和传递过程，该过程中电流主要由溶液、氧化膜和金属界面的产生-复合、扩散、隧穿和雪崩4种电子的转移过程所控制。由理论得到的腐蚀电位与电流的关系与相关的实验结果有很好的一致性，表明用量子力学从微观上揭示腐蚀的动力学机理是合理的

Abstract:

Knowing the correct corrosion mechanism of Alloy 690 is valuable for corrosion protection of equipment. Considering the semiconductor characteristics of metal oxide film on the corrosion surface, a new corrosion dynamics mechanism was proposed based on the quantum mechanics. At first, the nature and characteristics of currents were analyzed in different applied potentials by the band structures of metal. Then the relationship between corrosion potential and current was developed and the kinetic mechanism of corrosion was explained from microscopic view. The results show that the corrosion process is controlled by four kinds of electron transfer named generation-compound, diffusion, tunneling and avalanche in the interface of solution, oxidation film and metal. It is reasonable to interpret the polarization curve of Alloy 690 by quantum mechanics because this relationship has very good consistency with that of experiments