新型铁基超导线带材的研究进展

Recent Advances in Iron-Based Superconducting Wires and Tapes

新型铁基超导材料具有较高的临界转变温度、超高的上临界场和非常小的各向异性等优点,在高场磁体领域应用前景广阔。目前粉末装管法已广泛应用于铁基超导线带材的制备,临界电流密度在4.2 K和10 T下高达1.7×104A/cm2,接近实用化水平。首先介绍了铁基超导材料的典型结构与基本超导特性,详细评述了铁基超导粉末的合成和粉末装管法的工艺流程,主要包括元素配比、热处理工艺以及粉末装管原位法和先位法的对比分析,重点探讨了影响线带材临界电流密度的因素及其关键制备技术。通过包套材料的选择、掺杂改性、热等静压和轧制织构等方法来解决线带材中包套与超导芯易反应、杂相多、致密度低以及晶界弱连接等难题。此外还简要介绍了多芯线带材的最新研究进展。最后,对铁基超导线带材的发展趋势做了展望。

The newly discovered iron-based superconductors have caused great interest for high-field applications due to their good properties such as high transition temperature, ultrahigh upper critical field and low anisotropy. The iron-based superconducting wires and tapes are commonly prepared by the powder-in-tube （PIT） process. In this paper, we focus on the fabrication techniques to realize high Jc values such as chemical composition, optimal heating conditions, sheath mate- rial, doped elements, hot isostatic press and rolling texture, particularly for the 122-type pnictide wires and tapes. Excit- ingly, so far high transport Je value of 1.7 × 10^4 A/cm2 at 4. 2 K and 10 T has been obtained in iron-based tapes, closed to the practical level. Finally, a perspective and future development of PIT pnictide wires and tapes are given.