Synthesis of Bi2223 by Low P_ O2 Sintering

This is the authors' abstract. We don't add key points for this paper.

Silver-sheathed Bi(Pb)2223 tapes have been developed as the first-generation high-Tcsuperconducting material. Generally, a long-time sintering condition exceeding 100 h at 830 ~ 845 °C in PO2~ 0.08 atm has been fixed for more than 20 years to prepare Bi(Pb)2223. In addition, there are few studies on the optimization of PO2during sintering. In the present study, a low PO2(= 0.02 ~ 0.03 atm) synthesis was applied for fabrication of the Bi(Pb)2223 bulks and tapes. The silver-sheathed Bi(Pb)2223 tapes were prepared by sintering under various conditions including hot isostatic pressing treatment. Fine Bi(Pb)2223 grains were observed in the samples when the first sintering was performed in PO2~ 0.02 atm. This led to densification of oxide core by second sintering using hot isostatic pressing treatment (Ptotal= 100 atm), resulting in improvements of sharpness of superconducting transition and Icat 77 K.