High Temperature Knudsen Effusion-Mass Spectrometric Studies of the Y-BA-Cu-OSystem

摘要

The vaporization of copper from YBa2Cu3O(7-x) was studied by Knudsen EffusionMass Spectrometry (KEMS). The oxygen content at the starting temperature of the vaporization studies was inferred to be 6.24. The vapor pressures yielded activities and chemical potential differences of Cu in equilibrium with YBa2Cu3O(6.24). The residues after the experiments were found by X-ray diffraction to be principally Y2BaCuO5. The relative merits of BaCO3 compared to Ba(NO3)2 as precursor in the synthesis of YBa2Cu3O(7-x) superconductor were examined. Samples of YBa2Cu3O(7-x) were prepared using Y2O3, CuO and either Ba(NO3)2 or BaCO3. These samples were studied using KEMS and SEM-EDAX to determine if levels of carbonate in the sample were reduced by using Ba(NO3)2 as a starting material. The results showed that samples prepared using the nitrate compound were significantly lower in carbonate than the samples prepared using the carbonate.