论文部分内容阅读
以B4C粉末与Mg粉为原料,采用真空固相反应法成功制备了复相MgB2超导块材,研究了不同制备工艺下MgB2的成相,测量分析了材料的X射线衍射谱、扫描电镜图像、低温电输运特性等.结果显示,合成的复相超导材料含MgB2超导相、B4C绝缘相和少量MgB2C2杂相,MgB2超导相含量与B4C粒径、合成温度、反应时间等有关,并在30%~85%范围内分布.以粒径牌号W3.5(<5(m)的B4C与200目粒径Mg粉为原料、烧结温度800℃、保温时间1小时下制备的样品,MAUD(Material Analysis Using Diffraction)软件测得样品中MgB2的含量高达83.2%,其临界转变温度Tc0为31.5 K,起始转变温度Tc,on达34.0 K.零场10K下临界电流密度Jc高于0.5×106A/cm2.本文给出的原位合成不同超导相含量的MgB2复相超导材料对研究MgB2晶粒间弱连接特性具有重要意义,合成的超导材料晶粒尺度大,临界电流密度高,合成成本低廉,可应用于液氦温区和制冷机提供的20K温区的超导强电领域.
The B4C powder and Mg powder were used as raw materials to prepare MgB2 superconducting blocks by vacuum solid-phase reaction. The formation phases of MgB2 under different preparation conditions were investigated. The X-ray diffraction spectra and scanning electron microscope images , Low temperature electric transport characteristics, etc. The results show that the content of MgB2 superconducting phase, B4C insulating phase and a small amount of MgB2C2 heterogeneous phase and MgB2 superconducting phase are related to the particle size of B4C, synthesis temperature and reaction time , And distributed in the range of 30% ~ 85% .The samples prepared with the grain size W3.5 (<5 (m) B4C and 200 mesh Mg powder as raw materials, the sintering temperature of 800 ℃ and the holding time of 1 hour , MAUD (Material Analysis Using Diffraction) software measured the content of MgB2 in the sample as high as 83.2%, the critical transition temperature Tc0 was 31.5 K, the initial transition temperature Tc, on 34.0 K. The critical current density Jc at 10K under zero field 0.5 × 106A / cm2. The in-situ synthesis of MgB2 multiphase superconducting materials with different superconducting phases is of great significance for studying the weak connection between MgB2 grains. The synthesized superconducting material has large grain size and critical current High density, low cost of synthesis, can be applied to the liquid helium temperature and refrigerator provided 20K temperature superconductivity strong electric field area.