Fabrication and Microstructure Characteristic of YBCO Bulk by Directional Top-Seeded Power Melting Process

Top-seeded power melting process (TSPMP) is an effective melting processing technique for the preparation of high Jc bulk YBCO. The directional solidification is also a quite common technique used to produce well-oriented cylinder grains. The two processes were combined (named Directional Top-Seeded Power melting Process, DTSPMP) to fabricate good YBCO bulk with well-oriented domains. The seed transferring effect and the change of the solute concentration in liquid were analyzed. The effects of temperature gradient (TG) on the orientation and continuous growth of large grains were also investigated. The microstructure dependence on pulling rate was analyzed through scanning electric microscopy(SEM), and it is found that the large domains can be obtained and the fine dispersive 211 particles are entrapped at a slower pulling rate.