FABRICATION OF LARGE GRAIN YBCO BY SEEDED PERITECTIC SOLIDIFICATION

The ability to process large grain, uniform high temperature supercond ucting ceramics that exhibit high critical current densities at 77 K i s essential if the enormous potential of these materials for a range o f permanent magnet-type applications is to be realized. We report a st udy of the fabrication of large grain YBa2Cu3O7-delta by seeded perite ctic solidification in which key processing parameters such as the per itectic melting process, the seed-YBCO reaction, and the YBCO solidifi cation kinetics are investigated in detail. Evolution of the sample mi crostructure during various stages of the growth process, in particula r, has been studied extensively. The superconducting properties of spe cimens cut from different regions of large grain samples have been mea sured using vibrating sample magnetometry, and the results correlated with the microstructure of the materials.