EVALUATION OF STRUCTURE-RELATED PARAMETERS OF HOT-PRESSED BISCCO (2223) PHASE

Bi1.84Pb0.34Sr1.91Ca2.03Cu3.06Ox bulk superconductors were prepared by hot-pressing sintering in the range 790-830-degrees-C at 7 MPa in air for 2 h; keeping the temperature constant at 810-degrees-C, samples were also prepared varying the sintering time in the range 1-6 h. The density increases with increasing sintering temperature and time, as does the orientation factor (F) which is further strongly affected by time. The evaluation of the cell parameters shows an increase of both ''c'' and ''a'' on increasing the temperature up to 800-degrees-C; a continuous decrease is detected at higher temperatures. On the other hand a constant dilatation in the cell volume is detected as a function of the sintering time. The crystallite volume continuously increases with sintering temperature and time.