FORMATION OF BACEO3 AND ITS INFLUENCE ON MICROSTRUCTURE OF SINTERED MELT-TEXTURED Y-BA-CU-O OXIDES WITH CEO2 ADDITION

The formation of BaCeO3 and its effects on microstructure were studied in sintered/melt-textured Y-Ba-Cu-O oxides containing 5 wt. % CeO2 an d various amounts of Y2Ba1Cu1O5. The added CeO2 was converted to fine particles of BaCeO3 near 930-degrees-C, which is the conventional sint ering temperature for Y-Ba-Cu-O. Y2Ba1Cu1O5 and CuO are formed as by-p roducts of the reaction between CeO2 and Y1Ba2Cu3O7-y phase. The CeO2 addition reduced the particle size Of Y2Ba1Cu1O5 which was trapped in the Y1Ba2Cu3O7-y matrix after the melt-texture growth. During the peri tectic decomposition stage of Y1Ba2Cu3O7-y phase into Y2Ba1Cu1O5 and l iquid phase, the morphology of the decomposed Y2Ba1Cu1O5 was changed f rom a blocky shape in the undoped sample to an acicular shape of high anisotropy in the CeO2-added sample. The formation of the highly aniso tropic Y2Ba1Cu1O5 particles appears to be responsible for the refineme nt of Y2Ba1Cu1O5 particle after the melt-texture processing.