Effects of stoichiometry on sintered YBa2Cu3Ox

It is well established that several liquid-forming decomposition reactions can occur in the 123 system. The occurrence of these reactions is dependent on the phase assemblage of the starting powder and the sintering temperature and atmosphere used. By systematically varying the stoichiometry of the precursor powders, we have investigated how the presence or absence of liquids during firing affects microstructures and superconducting properties of sintered 123. We used an aqueous coprecipitation process to prepare the controlled stoichiometry precursor powders. By calcining the powders at ∼800 degree C, weakly agglomerated powders with a submicron grain size were produced. Results will be presented emphasizing the effects of stoichiometry on 123 microstructure and superconducting properties as a function of sintering temperature