超临界二氧化碳发电系统具有能量转化效率高、占用空间小和节水巨大等优点，在火电、核电等领域应用前景广阔。目前影响新型系统长周期安全运行的瓶颈之一是关键高温部件材料腐蚀问题，因为腐蚀过程中离子扩散和反应复杂，尤其是碳迁移及其反应产物，难以准确预测材料腐蚀寿命。项目以典型耐热钢为对象，通过热力学理论和实验研究超临界二氧化碳腐蚀产物类型及其形成机制，获得其成分、分布及演变规律。根据Wagner腐蚀扩散理论与反应产物分析温度、压力和杂质等环境参量对重要离子扩散的影响程度，探究稳定性反应产物形成、演化及损伤对离子扩散的影响规律，获得腐蚀过程中离子扩散规律及速率参量方程。在此基础上提出气相沉积复合薄膜抑制扩散方法，探究致密稳定保护膜形成及演变规律，从而揭示腐蚀过程中离子扩散与反应产物的交互作用机理。项目研究可丰富超临界流体腐蚀过程的扩散理论体系，为材料选型、腐蚀寿命预测和系统高效安全运行提供科学依据。

The supercritical carbon dioxide power generation system has the advantages of high energy conversion efficiency, small occupied space and huge water conservation. The system has broad application prospect in the fields of thermal power and nuclear power. At present, corrosion of critical high-temperature components is one of the bottlenecks that affect the long-term safe operation of the system. It is difficult to accurately predict the corrosion life of materials because of the ion diffusion and complex reaction during the corrosion, especially the carbon migration and its reaction products. The project studies the compositions, distribution and evolution of corrosion products of typical heat-resisting steel with thermodynamics theory and experimental research in the supercritical carbon dioxide environment. Based on Wagner corrosion diffusion theory and reaction products, the influence of environmental parameters such as temperature and pressure on ion diffusion will be analyzed. The effect of formation, evolution and damage of stable reaction products on ion diffusion is investigated to require the ion diffusion law and rate parameter equation. On the above basis, the method of suppressing the diffusion of vapor-deposited composite film is proposed. The formation and evolution of dense and stable protective film are explored to reveal the interaction mechanism between ion diffusion and reaction products during the corrosion. The project research will enrich the diffusion theory system of supercritical fluid corrosion process and provide a scientific basis for the prediction of corrosion life of heat-resisting steel and the efficiently safe operation of the supercritical carbon dioxide power generation system.