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采用原位法粉末装管工艺(in-situ PIT)制备了无定形碳掺杂MgB2/Nb/Cu超导线材并研究了该掺杂对MgB2微观结构及超导电性的影响。复合线材中以Nb作为阻隔层、Cu作为稳定体并采用冷拉拔工艺进行加工。研究了无定形碳掺杂对MgB2相形成、微观结构及超导电性的影响,其中掺杂量分别为MgB2-xCx(x=0.0,0.05,0.08,0.10,0.15)。分别采用XRD、SQUID、SEM/EDS及传输电流测试等方法对MgB2/Nb/Cu线材进行分析测试。XRD分析结果显示,700oC热处理后的线材可以获得纯度较高的MgB2超导相;微观结果照片显示无定形碳掺杂后可以获得良好的晶粒连接性;能谱分析表明掺杂物C元素均匀的分布在MgB2基体中;通过四引线法测试了传输临界电流密度Jc,在4.2K、5T,其Jc值高达1.4×105A/cm2;在4.2K、10T,其Jc值为3.3×104A/cm2。
The amorphous carbon doped MgB2 / Nb / Cu superconducting wire was prepared by in-situ PIT and the effect of the doping on microstructure and superconductivity of MgB2 was investigated. In the composite wire, Nb is used as a barrier layer, Cu is used as a stabilizer and is processed by a cold drawing process. The effects of amorphous carbon doping on the formation, microstructure and superconductivity of MgB2 phase were investigated. The doping amounts were MgB2-xCx (x = 0.0,0.05,0.08,0.10,0.15) respectively. The MgB2 / Nb / Cu wires were analyzed by XRD, SQUID, SEM / EDS and transmission current test, respectively. The results of XRD showed that the MgB2 superconducting phase with high purity could be obtained by the heat treatment at 700oC. The microscopic results showed that the amorphous carbon doped could obtain good crystallinity connectivity. The energy dispersive spectroscopy The critical current density Jc was tested by the four-lead method at 4.2K and 5T, and its Jc value was as high as 1.4 × 105A / cm2. At 4.2K and 10T, the Jc value was 3.3 × 104A / cm2 .