烧结温度对MgB2超导线材微观结构及超导电性的影响
Effects of Sintering Temperature on Microstructure and Superconductivity of MgB2 Wires
单 迪1,2, 刘国庆2, 闫 果2, 周 廉2
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作者单位：(1. 西北工业大学, 陕西 西安 710072; 2. 西北有色金属研究院, 陕西 西安 710016)
中文关键字：MgB2超导线材； 烧结温度； 微观结构； 超导电性
英文关键字：MgB2 superconducting wires; sintering temperature; microstructure; superconductivity
中文摘要：使用干燥的B粉和Mg粉，采用分步反应法制备了SiC(40～45 nm)掺杂的MgB2/Nb/Cu超导线材。通过X射线衍射仪、扫描电子显微镜，研究了不同烧结温度对所制备样品的相组成、微观结构的影响。采用标准四引线法测定了样品的电阻温度曲线。结果表明：热处理温度对线材的微观结构有显著影响，适宜的热处理温度可提高C原子实际进入晶格取代B原子的数量。在750 ℃× 2 h，C原子替代B的取代分数达3.73%。分步反应法制备MgB2超导线材可有效地引入B位C掺杂，从而提高线材在高磁场下的载流能力。
英文摘要：MgB2/Nb/Cu superconducting wires were fabricated by two-step PIT process using dry Mg and B powders and doping SiC(40～45 nm). The phase structure, microstructure was investigated by X-ray diffraction, scanning electronic microscopy. The resistivity temperature curves of MgB2 wires were measured by standard four-probe method. The results show that heat treatment temperature has a significant effect on the microstructure of wires, and appropriate sintering temperature increases the amount of C atoms diffusing into the lattice substitution for B atoms. The C substitution level is up to 3.73% at 750 ℃× 2 h. MgB2 superconducting wires fabricated by two-step PIT method can effectively introduce into C substitution for B position to enhance current-carrying capacity under high magnetic field.