电流差异化作用下金属连接体高温氧化机理研究

A strong electric current could lead to the abnormal high-temperature oxidation of metallic interconnects and thereby the fast increase in the area specific resistance, which limits the stable operation of solid oxide fuel cell (SOFC) stacks under a high load. In this study, with considering the differentiated effect of electric current on the ion migration, the rule and mechanmism of high-temperature oxidation under electric current are studied. Firstly, by carefully analyzing the nano- and micro- structures and the element distribution of the oxide scales, the rule for ion migration under electric current is examined, and the differentiated effect of electric current owing to the differences in the valence of ions and in the microstructure of oxide scales is revealed. Then, by using a novel method for the separating measurement of area specific resistance in the positive and negative sides,the oxidation kinetics under electric current is systematically studied. With considering the relation between ion migration and oxidation kinetics, the high-temperature oxidation mechanism under the differentiated effect of electric current is clarified. Furthermore, to improve the electrical properties and long-term stability of metallic interconnects, the low-temperature sintered coating technology is optimized. This study will clarify the rule and mechanism for high-temperature oxidation of metallic interconnects under electric current. It will also provide a scientific basis for the performance and life prediction of metallic interconnects, and a theoretical basis for the development of SOFC interconntct materials and technologies.

金属连接体在强电流条件下出现异常高温氧化并导致面电阻快速增长，制约了固体氧化物燃料电池（SOFC）的高负载稳定运行。本项目从电流对氧化过程中离子迁移的差异化作用入手，开展电流作用下金属连接体的高温氧化规律和机理研究。通过纳微尺度氧化膜结构和成分分布研究离子在氧化产物中迁移规律，揭示由离子价态和氧化膜微观结构等因素导致的电流对离子迁移的差异化作用机制。发展正负极面电阻分离测试新方法，系统研究电流作用下合金高温氧化动力学规律。建立微观迁移机制和宏观氧化规律之间的关联，阐明电流差异化作用下金属连接体高温氧化机理。优化自主知识产权的低温烧结涂层技术，提高金属连接体在强电流条件下的导电性能和长期稳定性。本研究将阐明电流作用下金属连接体高温氧化规律和机理，为金属连接体性能和寿命预测提供科学依据，为发展SOFC大电流连接材料和技术提供理论基础。

金属连接体在强电流条件下出现异常高温氧化并导致面电阻快速增长，制约了固体氧化物燃料电池（SOFC）的高负载稳定运行。本项目从电流对氧化过程中离子迁移的差异化作用入手，开展电流作用下金属连接体的高温氧化规律和机理研究。主要研究工作如下：（1）电流作用下离子迁移的差异化规律和机制；（2）电流作用下金属连接体的高温氧化动力学规律；（3）基于电流差异化作用的金属连接体高温氧化机理；（4）针对电流作用的防护涂层优化。通过以上研究，探明了电流对氧化过程中离子迁移的差异化作用及其机制，揭示电流作用下Fe-Cr合金高温氧化规律和机理，为金属连接体性能和寿命预测提供科学依据。此外还提出和验证了控制电流负面影响的金属连接体涂层防护对策，为发展SOFC 电连接材料和技术提供理论基础。