SOL-GEL PREPARATION AND FLUORINE SUBSTITUTION OF BISCCO HIGH-T-C SUPERCONDUCTORS

Sol-gel citrate technology was used to prepare BiSCCO 2223 and 2212 su perconducting phases. Fluorine in the initial mixture was shown to enh ance considerably formation of the 2223 phase. Fluorine substitution o f up to three F atoms per Bi(Pb)SCCO 2223 formula was achieved by trea tment of the sample in 80 Torr ClF3 atmosphere. A number of experiment al methods have been used to characterize the samples and to trace the phase transformations in the sol-gel process: DTA/TG, XRD, atomic abs orption, potentiometry with fluoride selective electrode, magnetic sus ceptibility measurements.