Optimum conditions for synthesizing YBa2Cu3Ox

The effect of raw materials on preparing the high Tc superconductor YBa2Cu3Ochi (the 123 compound) was studied in a simultaneous analyzer using various barium compounds with Y2O3 and CuO. The rate of reaction was found to be faster in air or in slightly reducing atmospheres than in pure oxygen, implying that the solid state reaction should be carried out in air. The kinetic parameters for the solid state reaction of Y2O3, BaCO3 and CuO to form the 123 compound in air were calculated from the results obtained at different heating rates. Rules for equilibrium relationships in non-condensed systems are reviewed and applied to the quaternary Y-Ba-Cu-O in air. Quasi-binary and ternary sections of importance in preparing the 123 compound are shown