Heat treatment on phase evolution of Bi-2223 precursor powder prepared by spray pyrolysis method |
SEM micrographs of precursor powders heat-treated at 770 °C in N2-0.1%O2 atmosphere for different times: (a) 4 h, (b) 8 h, (c) 12 h, (d) 16 h, (e) 20 h, (f) 24 h. |