Direct Observations of Melting and Solidification of Bi–Pb–Sr–Ca–Cu–O Compound

Abstract

Melting and solidification of Bi–Pb–Sr–Ca–Cu–O compound were directly observed by means of high-temperature optical microscopy. Crystals which appeared in heating and cooling processes were analyzed by means of micro-X-ray diffraction analysis and electron probe microanalysis. In heating, a pressed powder of the high-Tc phase, (Bi, Pb)2 Sr2Ca2Cu3Oy, started melting at about 910°C and the melt was separated into two different liquid phases on a sapphire plate at about 1000°C. In cooling, crystals of the Ca2CuO3 phase and the low-Tc phase, (Bi, Pb)2Sr2CaCu2Oy, were obtained from these two liquid phases and no single crystals of the high-Tc phase appeared.