不同热处理条件下Bi-2212超导线材的临界性能研究

摘要

Bi-2212高温超导材料在4.2K具有优异的磁场载流性能,并且是目前高温超导材料当中唯一可制备成各向同性圆线的材料,可以绞制成大电流的CICC电缆,也是大型超强磁场磁体的首选材料之一.高压热处理技术可以大幅提高材料超导性能.临界电流与n值是超导导线的主要性能参数.本文测量了两组分别经过常压和高压热处理的超导线在不同背景磁场中的临界电流和n值.测试所用Bi-2212导线是以Ag和Ag/Mg合金为基体,采用粉末装管法制备而成,两组导线在890℃下经不同压强热处理.从对比的数据中定性地分析热处理压强和超导线性能之间的关系.%At 4.2K,the high temperature superconducting material Bi2212 has an outstanding conductor-carrying capacity in magnetic field.And it is the only superconducting material that can be made into isotropic round-wire currently,which makes it possible to develop a CICC (Cable-In-Conduit Conductor).It is also one of the preferred magnet materials chosen for high magnetic application.The heat treatment with high pressure can improve its performance greatly.The critical current and n values are the main parameters of superconducting strand.In this paper,two types of PIT Bi-2212 Ag,Ag/Mg base round wires were measured with different back ground.These two types of sample were heat treated at 890℃ with different pressures before the experiment.By comparing the results of two types of samples,we could conclude the effect of pressure on Bi-2212.