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

The preparation of BPSCCO-Ag composites by an innovative wet method is described, which allowed admiring of silver in the form of a solution to the solution containing all other cations, and the decomposition o f the organic matter in a mild and reproducible way. The citrate route was used without the use of nitrates, ethylene glycol or other reticu lating or complexing agents. After drying, silver was found to be disp ersed in the powder in metallic form. The powders were treated in an a tmosphere containing nitrogen oxides in order to reduce the carbon con tent. The powders so prepared were suitable for ''powder in tube'' pro cessing in that they were very reactive toward the 2223 formation and may contain only the desired phases: 2212, metallic silver and Ca2PbO4 which, when present in excess, produce a flux that helps texturing an d full phase conversion. Preliminary results on the high-purity sample s prepared by the powder in tube process show a steady increase of J(c ), with the absence of a maximum of J(c) with number of treatments, an d high texturing of the powder inside the tube.