Characterization and phase transitions of (Bi,Pb)2Sr2Ca2Cu3Ox–Ag composite powder obtained by spray pyrolysis

(Bi,Pb)2Sr2Ca2Cu3Ox–Ag (BPSCCO/Ag) composite precursor powder was prepared by spray pyrolysis. The as-prepared and thermally treated (750 °C (1 h) and 780 °C (3 h)) powders were characterized by transmission electron microscopy, ambient X-ray diffraction, In situ X-ray diffraction, magnetic susceptibility measurement and differential thermal analysis (DTA). DTA curve exhibited two strong endothermic peaks above 790 °C, one very wide with the onset at 790 °C and the second at 840 °C. In situ X-ray diffraction measurements strongly supported the view that the first endothermic peak was due to Ca2PbO4 decomposition and a transient liquid formation through PbO–CuO–Ag eutectic. The second endothermic peak can be explained by onset of Bi-2212 peritectic melting that began at 840 °C with local formation of Bi-2201 intergrowths. The melting was complete at 875 °C.