基于电化学/化学反应和扫描电化学显微镜技术的钛及其合金腐蚀动力学研究

腐蚀电化学反应有两大主要特征，非平衡和多反应耦合。线性极化区和弱极化区表观电流通常是两个及以上反应的耦合电流，限制其动力学分析，而塔菲尔区的选择又存在偶然性，其本质原因是对腐蚀阴阳极反应的反应历程，及其动力学缺乏准确研究。本课题创新性地提出采用腐蚀金属超微电极为探针，铂/金微电极为基底，应用扫描电化学显微镜探针产生-基底收集模式，开展钛及其合金，在酸性、中性和碱性环境下、有氧与无氧条件中的全极化范围内阳极溶解反应与阴极还原反应的定量分离，并应用COMSOL构建空间二维和三维模型，获得动力学特征参数，并进一步研究海洋环境典型阴离子种类和浓度、温度、以及氧化膜/腐蚀产物膜对阳极溶解动力学与阴极还原动力学的影响规律，及其可能的影响机制。该项目从基础电化学反应出发，以海洋钛合金材料为背景，深入认识腐蚀电化学反应特征和动力学行为，明确腐蚀反应机制，为发展非平衡电化学提供基础，具有重要的科学意义。

Corrosion electrochemical reactions have two main characteristics, nonequilibrium and multi-reaction coupling. In the linear polarization and the weak polarization region, the apparent current usually consists of at least two the coupling current of the reactions, which limits its kinetic analysis, while the accurate selection of the Tafel range is difficult. The essential reason for this phenomenon is the complexity of the cathodic and anodic reactions of the corrosion electrochemical, and the lack of accurate study of its kinetics. In this proposal, the use of corrosive metal ultrafine electrode as tip, platinum/gold microelectrode as the substrate are conducted with modified tip generation-substrate collection mode of scanning electrochemical microscope. The development of typical metal materials, especially for titanium and its alloy, in acidic, neutral and alkaline environment, are chosen as typical corrosion metal. The anodic dissolution reaction and cathodic reduction reaction in the full polarization range in aerobic and anaerobic conditions are quantitative separated. Then the COMSOL is used to construct a space two-dimensional model, to obtain the kinetic characteristic parameters, and to further study the typical anion species and concentration, temperature in marine, as well as the effect of oxide film/corrosion product film on the metal anodic dissolution kinetics and cathodic reduction kinetics, and its possible influence mechanism. Based on the basic electrochemical reaction and marine titanium alloy material as the background, the project has an in-depth understanding of the characteristics and kinetic behavior of corrosive electrochemical reactions, and it is of great scientific significance to clarify the mechanism of corrosion reaction, which also provides a basis for the development of nonequilibrium electrochemistry.