INTRINSIC KINETICS OF CARBON-DIOXIDE DEGRADATION OF YBA2CU3O7-X

The intrinsic kinetics, unaffected by diffusional and mass-transfer effects, of the CO2 degradation of superconducting particles have been determined using a nonisothermal technique. Below 900-degrees-C, the carbonization of YBa2Cu3O7-x leads to formation of BaCO3, Y2Cu2O5, CuO, and Cu2O. A further increase in temperature results in formation of BaCuO2 from BaCO3 and CuO. The carbonization rate shows the 1.5th-order dependence on the amount of unreacted YBa2Cu3O7-x for the temperature range of 550-degrees to 815-degrees-C. The activation energy of carbonization was determined to be 95.1 kJ . mol-1.