MANUFACTURE OF FINE-GRAINED Y2BACUO5 POWDER BY COPRECIPITATION

Quantities of Y2BaCuO5 powder greater than 500 g have been manufactured by a co-precipitation process. By suitable heat treatments, the particle size of these powders can be varied from 5 mu m to less than 500 nm. Sub-micrometer size powders may, under some conditions, have a duller green colour which is attributed to <2% unreacted material. However, after re-grinding and re-firing of this powder, high-purity powders can be achieved without significant grain growth. Inductively coupled plasma (ICP) spectroscopy is used to measure the stoichiometry of the powders and X-ray diffraction is used to determine phase purity. In both cases, the bulk composition is consistent with Y2BaCuO5 and phase purity is considered better than 95%.