高能球磨法制备MgB2材料的研究进展

Research Progress of MgB2 Superconducting MaterialsPrepared by High-energy Ball Milling

摘要:

MgB₂超导体临界温度为39 K,具有价格低廉和临界转变温度相对较高等优点,具有工程应用前景,然而其大尺度应用还依赖于超导性能的改善。经过系统的研究发现高能球磨和元素掺杂是提高MgB₂磁场下J_c性能最有效的方法。本文介绍了采用高能球磨法制备MgB₂的研究现状,采用高能球磨能有效细化晶粒,有利于提高超导芯丝的致密度,强化MgB₂晶粒的连接性,同时晶粒细化形成的更多晶界能形成钉扎中心,进一步提高线/带材在高磁场下的临界电流密度。我们还介绍了通过分步反应法和高能球磨在常压条件下合成MgB₂,高能球磨法可以减少MgB₂长线中的孔洞并提高粉体密度。

Abstract:

Since the discovery of superconductivity at 39 K in MgB₂, it has been considered as one of the most promising candidates for engineering applications due to its low material cost and relativity high critical transition temperature. However, the realization of large-scale application for MgB₂ based superconducting technology essentially relies on the improvement of superconducting properties of MgB₂. Some techniques have been developed to improve the critical current density, such as chemical doping, high-energy ball milling and various processing techniques. We introduce some research progress of MgB₂ superconducting materials prepared by high-energy ball milling. The investigation showed high-energy ball milling is effective to obtain high density and fine grain size MgB₂with high J_c performance. We also introduce that high J_c MgB₂ was synthesized by two-step reaction method and high-energy ball milling. High-energy ball milling may be a good choice for reducing the void percentage and enhancing the average density in MgB₂ long wires.