Powder preparation by organic precursor and densification of a high-T_c Bi-based superconductor

Homogeneous and reactive superconducting precursor powders were prepared by the pyroysis technique starting from a solution of citrates. Pyrolyzed organometallic precursors were fired to obtain a superconducting powder: multi-step synthesis at 855°C of only 24 h was found to be adequate to produce a high-purity (2223) phase. Dense superconducting materials were prepared and compared with those obtained from solid-state-reacted powders. To promote densification hot-pressing was used and the effect of the sintering parameters on the compositional, microstructural and functional characteristics of the material was evaluated.