Bi(Pb)-Sr-Ca-Cu-O (2223) superconductor prepared by improved sol-gel technique

A particular sol-gel process for preparation of BSCCO (2223) powder was devised, settled and tested. Water-in-oil type emulsion technique associated to internal gelation process was chosen, starting from cations' nitrates. Dried powders were calcined for a few minutes at 400°C and then fired at 850°C in steps of 5 h with intermediate grindings: in only 14 h 92% pure (2223) phase was obtained. Powder mean particle size resulted very low (<1 μm) and morphology is characterized by globular grains which are both promising features for subsequent pressure sintering technique. Moreover, the method appears well adaptable to large scale production.