铁钝化膜中光生载流子与离子缺陷耦合动力学研究

This project studies the correlation between the kinetics of ion-defects migration and electrochemical, spectroscopic conditions aiming at coupling effect of photo-induced carriers and ion-defects in passive film on iron. To illustrating the effect of incident light wavelength, intensity and polarization potential, current on the structure and electronic characteristics, an analysis of passive film on photo-electrochomical method is introduced. The dependency between the growth and dissolution of passive film and photo-induced electrical field is evaluated around the migration process of ion-defects. The photo-electrochomical behaviors under different spectroscopic conditions are analyzed and tested by using intensity modulated photo current/voltage spectrum, phase analysis and Transient absorbance spectrum methods. The interrelationship between the electronic characteristics and ion-defects migration is revealed on the basis of the comprehensive analysis of composition, structure, defect density, electric field strength and photo-induced carriers in passive film. This is an attempt to clarify the physical-chemical mechanism of ion-defects migration in the growth and dissolution process of passive film. It's of great significance to further the research of the kinetics of growth and breakdown of passive film on iron to understand the nature of electronic characteristics of passive film on the corrosion behavior of metals.

本项目针对铁表面钝化膜中光生载流子与离子缺陷具有相互耦合作用的特点，研究电化学条件、光谱条件与钝化膜中离子缺陷迁移动力学之间的相关性。通过在铁表面钝化膜研究中引入光电化学分析，阐明入射光强度、波长和极化电位、电流等光电化学参数对钝化膜结构和电子特性的作用规律。围绕钝化膜中离子缺陷迁移过程，重在评估钝化膜生长、溶解与光致电场之间的依赖关系。通过对不同光谱条件下钝化膜光电化学行为的测试与分析，采用强度调制光电流/电压谱、表面物相分析和瞬态吸收光谱等方法，在综合对比考察钝化膜成分、结构、缺陷浓度、电场强度、光生载流子等参量对钝化膜中离子缺陷迁移影响的基础上，明确电子特性与钝化膜生长动力学之间内在的规律性。旨在阐明钝化膜生长、溶解过程中离子缺陷迁移的内在物理化学机制。项目对于促进铁表面钝化膜生长、破裂理论的完善，推进有关铁表面钝化膜中电子特性对其腐蚀行为作用机理与规律的深层次研究具有重要意义。

本项目利用金属钝化膜中光生载流子与离子缺陷相互耦合作用，研究了钝化膜生长、溶解动力学与膜内光生电场强度及电子特征相关性。围绕光生电子、空穴及其诱导电场对钝化膜内离子缺陷迁移影响及表面热空穴氧化现象，通过电化学、光电化学、材料表征等分析测试手段，探明了光生载流子对钝化膜生长、溶解及电子特性作用机理，获得了不同光谱条件下n型钝化膜内光致电场形成规律，建立了光致电场与钝化膜厚度及成膜电位之间的量化关系，揭示了n型钝化膜内电场强度在膜生长、溶解过程中不随膜厚度及成膜电位改变的特性。本项目研究将促进钝化膜生长动力学理论完善，有助于更精确预测金属部件腐蚀损伤失效过程及服役寿命。