Influence of vanadium oxide on BSCCO (2223) phase formation and related properties

The preparation of BSCCO 2223 superconducting powder was studied with addition of V2O5 ranging from 0.3 to 0.5 molar index. Various compositions were prepared both containing and without Pb and subsequently treated with different firing cycles, to promote the incorporation in lattice sites of vanadium atoms. Different densification procedures were attempted and final bulk samples characterized to evaluate microstructural, mechanical and electrical properties. The addition of vanadium was found to increase the formation rate of high Tc phase and about 90% of 2223 phase has been obtained in 80 h. However, this element was found to present an outstanding segregation trend at grain boundaries (especially with Sr) and to be responsible of a marked delay in 2223 phase formation in respect to lead-doped samples. Transport properties seem positively affected even if considerable contamination at grain boundary and lowering in offset critical temperature are unavoidable.