Reaction pathways for the formation of the YBa2Cu3O7−x compound

摘要: The kinetics of the reactions that lead to formation YBa2Cu3O7−x was investigated starting from various powder mixtures containing different reactants as sources Ba, Cu, and Y (BaCO3, BaO, CuO, Y2O3. Y2Cu3O5. BaCuO2). These powders were calcined at 940 °C for time intervals. Quantitative x-ray analysis used determine relative amounts compounds present in powders. When BaCO3 source barium, long calcination times required obtain single phased because slow decomposition BaCO3. This leads large particles broad particle size distributions hence a lower density sintered superconducting pellets. Procedures attain high material are identified on basis kinetic studies. Each them isolates reaction first step prepares via rapid second step. studies reveal mechanisms followed cases.