混合粉末对先位法MgB_2超导带材性能的影响

Influence of Powder Mixtures on Properties of the Ex-Situ MgB_2 Superconducting Tapes

将掺杂纳米C或SiC的预烧结粉与镁粉和硼粉进行混合作为先位(ex-situ)粉末套管法(Powder-In-Tube)的填充粉末,制备出MgB2/Fe超导带材。结果表明,掺杂纳米C或SiC样品的临界转变温度均比未掺杂样品的低1.5K左右。纳米C或SiC样品的临界电流密度(Jc)均得到了极大的提高。且在4.2K,8T下,掺杂纳米C样品的Jc最高,约为104A/cm2,比未掺杂样品以及采用商业MgB2制备样品的Jc高约1个数量级。在预烧结过程中纳米C或SiC中的C对B位的有效替代所产生的晶格畸变以及晶粒连接性的提高可能是掺杂样品的Jc提高的主要原因。

The MgB2/Fe superconducting tapes were fabricated with Mg, B and presintered MgB2 with doped C or SiC powder mixtures. It was found that the critical transition temperature （Tc） for C or SiC nanoparticle doped sample was lower than that for the pure sample. The Jc value for nanoscale C or SiC doped samples was strongly enhanced. And the Jc value for nanoscale C doped samples was about 104A/cm^2 （4.2 K, 8 T）, which was at least a factor of ten higher than that for the sample made from commercial MgB2 powders. The improvement of Jc properties in C or SiC doped MgB2 tapes is probably attributed to good grain linkage and the flux pinning induced by distortion of crystal lattice.