Direct Preparation of Uniformly-Distributed YBa₂Cu₃O7-x Powders by Spray-Pyrolysis

Fine powders of the compound YBa 2 Cu 3 O 7- x have been prepared directly by the spray-pyrolysis of aqueous solutions of corresponding metal nitrates. The powders obtained in a temperature range of 900 to 1000°C were spherical and their diameters were uniformly distributed below 1 µm. The crystallinity of these powders was increased with increasing decomposition temperature; an orthorhombic single phase was indeed obtained at 1000°C. The sintered bodies from these powders showed the offset of superconducting transition at 84 K.