High Jc Ti-doped MgB2 disks were synthesized by two-step reaction method and high-energy ball milling. In the first step, the sample with a nominal composition of Mg0.8Ti0.2B4 was sintered at 900 °C for 2 h. In the second step, an appropriate amount of Mg was then added to get the stoichiometry of Mg0.9Ti0.1B2, which was milled for 5 h and sintered at 750 °C for 2 h. The phase, microstructure and superconductivity of MgB2 were characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and superconducting quantum interference device (SQUID). The critical current density reaches 6.9 × 104 A cm-2 at 20 K and 1 T. The investigation showed the efficient combination between two-step reaction method and high-energy ball milling is effective to obtain high density and fine grain size bulk MgB2 with high Jc performance.
Yang, F., Li, S. Q., Yan, G., Feng, J. Q., Xiong, X. M., Zhang, S. N., … Feng, Y. (2015). Improved superconducting properties in Ti-doped MgB2 prepared by two-step reaction method and high-energy ball milling. Journal of Alloys and Compounds, 622, 714–718. https://doi.org/10.1016/j.jallcom.2014.10.186