Heat treatment on phase evolution of Bi-2223 precursor powder prepared by spray pyrolysis method |
SEM micrographs of precursor powders heat-treated in N2-0.1%O2 atmosphere at different temperatures: (a) 730 °C/6 h, (b) 750 °C/6 h, (c) 770 °C/6 h, and (d) 790 °C/6 h. |