CRYSTALLIZATION OF A BI-PB-SR-CA-CU-O SYSTEM PREPARED BY A MELT PROCESS

We prepared Bi1.6Pb0.4Sr2Ca2+2xCu3+xOy (x = 0.1 and 0.2) ceramics by a melt-quenching process, and examined crystallization behaviour. The activation energies of crystallization for the amorphous Bi1.6Pb0.4Sr2Ca2.2Cu3.1Oy and Bi1.6Pb0.4Sr2Ca2.4Cu3.2Oy were obtained by means of the Kissinger method; these values correspond to 477 and 468 kJ mol-1 respectively. The values of the activation energies for the amorphous Bi-system ceramics were a little bit larger than those of the amorphous alloys. The amorphous Bi-Pb-Sr-Ca-Cu-O ceramic was crystallized by heating in sequence though the phases: amorphous, semiconducting Bi2Sr2Cu1Oy, low-T(c) superconducting Bi2Sr2Ca1Cu2Oy and high-T(c) superconducting Bi2Sr2Ca2Cu3Oy.