Effects of heating rate on the phase and microstructure evolution in Bi-2223/Ag/Ni superconducting tapes

Effects of heating rate on the phase and microstructure evolution in Bi-2223/Ag/Ni superconducting tapes were studied. It was found that 30 °C/h, the lowest heating rate, was the most suitable to obtain microstructure improved tapes. The volume fraction of Bi-2223 phase increased and the amount and size of secondary phases decreased with the heating rate reducing. Meanwhile, the optimal texture formed earliest in the samples heated at 30 °C/h. The size of Bi-2212 grains is the largest in the samples heated at 30 °C/h, which may lead to the largest size of Bi-2223 grains eventually.