RAPID FORMATION OF THE HIGH-T-C PHASE IN (BI,PB)-SR-CA-CU-O SUPERCONDUCTOR VIA THE SOL-GEL METHOD

Bi-Pb-Sr-Ca-Cu-O powder was synthesized by the oxalate gel method. A s ample with the composition of Bi1.7Pb0.4Sr1.6Ca2.4Cu3.6Oy was used in this study. After pyrolysis of the gel precursor at 500 degrees C for 5 h, the resulting powder was calcined at 850 degrees C for another 5 h. The black powder was pressed into pellets and sintered at 852 degre es C for 5 h. The high-T-c phase was formed more easily in the sample with excess calcium and copper than in the theoretical composition. (B i,Pb)(2)Sr2Ca2Cu3Oy (above 90%) was prepared as above within a relativ ely short time. Characterization of (Bi,Pb)(2)Sr2Ca2Cu3Oy superconduct or by X-ray diffraction, scanning electron microscopy, electron probe microanalysis, resistivity measurement and magnetic measurement, is re ported.