Sol-gel processing of precursor for high-T-c superconductors: influence of rhenium on the synthesis of Ba2Ca2Cu3Ox

摘要

A sol-gel method for processing precursors of mercury-cuprates is described. It uses the gelification of a solution by acrylamide polymerisation and may be applied to concentrated solutions if a proper stabilisation of the cations is ensured. The method is described here for Ba2Ca2Cu3Ox and Re0.25Ba2Ca2Cu3Ox but may serve to other precursors. Barium carbonate contamination is avoided in a large extent and Re-addition even helps by its efficient combination at low temperature with barium species. The precursor, with Re, might be handled without complicated precautions. Superconductors have been prepared in this way with an excellent homogeneity and high T-c. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 30]