热处理温度对碳掺杂MgB_2/Nb/Cu超导线材性能的影响  

EFFECT OF HEAT-TREATMENT TEMPERATURE ON MgB_2/Nb/Cu WIRES WITH CARBON DOPING

作　　者：王庆阳[1,2] 闫果[1] 刘国庆[1] 焦高峰[1] 熊晓梅[1] 冯勇 张平祥[1,2,3] 

机构地区：[1]西北有色金属研究院,西安710016 [2]西北工业大学材料学院,西安710072 [3]西部超导材料科技有限公司,西安710018

出　　处：《低温物理学报》2010年第2期133-137,共5页Low Temperature Physical Letters

基　　金：国家自然基金(项目编号:50672077;50877067);"863"计划(项目编号:2007AA03Z237);"973"计划(项目编号:2006CB601004)资助课题

摘　　要：采用Nb/Cu复合管作为外包套材料,通过原位法粉末装管工艺(PIT)制备了C掺杂MgB2/Nb/Cu线材.在高纯流动氩气保护条件下、650～950℃温度区间内烧结2h.微观结构分析显示,通过该工艺制备的MgB2/NbZr/Cu线材具有良好的晶粒连结性和较高的致密度.X射线衍射(XRD)分析表明在750℃左右可以生成纯度较高的MgB2相,在低温和高温下烧结后均有杂相峰出现,并且高温烧结后所生成的相结构较为复杂.采用四引线法超导临界电流的测试结果表明,低温烧结后的线材具有超导电流传输性能,而当热处理温度超过750℃时,样品中的电流传输状态表现为正常电阻态.实验结果证实采用Nb作为原位法MgB2超导线材的包套阻隔层时,成相热处理一般应该在低于750℃的温度下进行.MgB2 wires doping with amorphous carbon were fabricated through the in-situ powder-in-tube method by using Nb/Cu composite sheath. Short samples of MgB2/Nb/Cu wires were sintered at 650～950℃ for 2h in flowing high-purity argon. The microstructure observation for wires showed that MgB2/NbZr/Cu wires have better grain connectivity and higher density. X-ray diffraction （XRD） show that higher purity MgB2 phase was acquired after heat-treatment at 750℃,the impurity phase was appeared at lower or higher temperature and the phase formation was more complicated at higher temperature. Critical current density （Jc） of the wires were measured in the different magnetic field by standard four probe method,the result show that the wires ambition the normal state when the heat-treatment temperature Higher than 750℃. This indicated that the MgB2 wires should be heat-treatment at lower than 750℃ while using the Nb as the sheathing.

关 键 词：二硼化镁线材 热处理温度 碳掺杂 超导电性 

分 类 号：TM26[一般工业技术—材料科学与工程] TG156[电气工程—电工理论与新技术]