BPSCCO-AG POWDERS OBTAINED BY A WET METHOD AND WITH A LOW-CARBON CONTENT FOR TAPE PREPARATION

High-T-c superconductors with nominal composition Bi1.8Pb0.4Sr2Ca2.2Cu 3Ox and eventually admired with metallic silver were prepared by an or iginal version of the citrate route which permits an excellent intersp ersion of the elements and makes no use of nitrates. After exsiccation , silver is found to be in metallic form with crystal size of about 30 0 Angstrom. After the decomposition of the organic part, a special tre atment was found to reduce the carbon content and to obtain only the d esired phase composition, i.e. 2212, Ca2PbO4 and metallic Ag. The powd ers obtained show high reactivity in the high-T-c phase formation and very little weight loss during calcination. Tapes prepared with the po wder-in-tube method showed high J(c) values and constant improvement a fter several thermal treatments.