Microstructure and superconducting properties of Bi-2223/Ag tapes fabricated in the variation-temperature-sintering process

The microstructure and superconducting properties of Bi-2223/Ag tapes fabricated in the variation-temperature-sintering process without magnetic field were investigated. The results showed that all tapes variation-temperature-sintered from low temperature to high temperature or from high temperature to low temperature in the first 24 h sintering process showed stronger c-axis alignment of the Bi-2223 phase than that isothermal-temperature-sintered. However, the tape processed by the variation-temperature-sintered from low temperature to high temperature showed a low proportion of the Bi-2223 phase. When the starting temperature (above 850°C) of the variation-temperature-sintering from high temperature to low temperature is too high, the proportion of Bi-2223 phase decreases largely. The tape variation-temperature-sintered from 845 to 835°C for 24 h and then isothermal-temperaturesintered at 835°C for 96 h showed a strong c-axis alignment of the Bi-2223 phase, a high proportion of Bi-2223 phase, and the highest Jc value.