铁基超导材料原位烧结织构形成机制及其载流能力研究

铁基超导材料因其较高的超导转变温度和优异的上临界场，在高磁场领域有很广阔的应用前景。但目前制备的铁基超导材料的载流能力都比较低，远远达不到实用要求。如何提高铁基超导材料的载流能力成为超导领域的研究热点。由于铁基超导体中存在晶界弱连接现象，在铁基超导材料中形成一定的织构可以降低晶粒间取向差，从而达到显著提高其载流能力的目的。据此，本项目提出在铁基超导材料原位烧结过程中添加合适烧结助剂，简便、有效地形成超导织构的设想。拟在澄清铁基超导材料烧结成相动力学机制的基础上，选取合适的烧结助剂，在烧结过程中引入低温活性液相，促进超导相形成与溶解，然后通过温度和浓度等工艺参数的控制，重新析出形成晶间连接良好的超导相织构。本项目的成功实施有望大幅提高铁基超导材料的载流能力，同时也可以获得铁基超导材料中烧结成相机理以及微观组织结构与超导性能之间的一般规律，为进一步合成具有更佳超导性能的铁基超导材料提供参考。

The Fe-based superconducting materials have a wide application prospect due to their higher transition temperature and excellent upper critical field. However, the development of Fe-based superconducting materials application is limited by their poor current carrying capability. How to improve current carrying capability of Fe-based superconducting materials has become the hot topic of research in the superconducting field. Recently, it is found that the critical current density in the Fe-based superconducting materials is remarkably deteriorated due to the presence of weak link grain boundary. Formation of texture in the Fe-based superconducting materials can decrease the weak link grain boundary and thus significantly improve current carrying capability through reducing the misorientation between grains. In present project, it is proposed that the formation of texture in the Fe-based superconducting materials can be realized effectively and conveniently during their in-situ sintering process with addition of proper sintering aid. Based on the formation kenitics of superconducting phase in the Fe-based superconducting materials prepared by sintering, proper sintering aid will be determined to add into the in-situ sintering process of Fe-based superconducting materials and form low-temperature sintering liquid in which the superconducting phase can be acceleratedly formed and dissolved. Then the regulatable texture of superconducting phase that possesses excellent grain connectivity will be formed from this sintering liquid through controlling process parameters (concentration,temperature, etc). The sucessful implementation of this project can obviously improve current carrying capability of Fe-based superconducting materials and promote their practical application. Moreover, the formation kenitics of superconducting phase during sintering process and the relationship between the microstructure morphology and current carrying capability in the Fe-based superconducting materials will be clarified, which can provide theoretical guidance for the fabrication of Fe-based superconducting materials with higher superconducting properties in future.