FUNDAMENTAL MATERIAL ASPECTS UNDERLYING THE PREPARATION OF HIGH-TEMPERATURE SUPERCONDUCTING (BI,PB)(2+X)SR2CA2CU3O10+D CERAMICS

Phase equilibria of the quasi-quinary system Bi3O3-PbO-SrO-CaO-CuO wer e studied between 650 degrees and 900 degrees C in air with emphasis o n the high-temperature superconducting phase (Bi,Pb)(2+x)Sr2Ca2Cu3O10d (2223). The 2223 phase lies in equilibrium with a number of nonsuper conducting phases and also with the superconducting phase (Bi,Pb)(2)Sr -2-CaCu2O8+d (2212). The single-phase region was found to be very limi ted. The Ph solubility of the 2223 phase is strongly temperature depen dent. The phase relations are very sensitive to variations of the cati on concentration and temperature. This effect significantly influences the preparation of 2223 ceramics.