GRAIN ALIGNMENT IN BULK YBA2CU3OX SUPERCONDUCTORS BY ISOTHERMAL PERITECTIC REACTION PROCESS

Abstract

An isothermal peritectic reaction (IPR) process has been developed to fabricate YBa2Cu3Ox (123) superconductors with aligned grain structure in a relatively short time without a temperature gradient. The process consists of the preparation of Y2BaCuO5 (211) powder compact in wire form and infiltration of a Ba-Cu-O glass melt into the 211 compact below the peritectic temperature of approximately 1010-degrees-C. During the infiltration at 965-degrees-C the 123 phase forms at the surface of the compact by the reaction between 211 grains and the glass, and the newly formed 123 grains grow directionally towards the center of the compact. The result of the infiltration is an aligned grain structure with a preferred orientation of {100} planes in the axial direction of wire-type compacts. These 123 superconductor specimens show the zero resistance (T(c)) at 92 K and transport critical current density (J(c)) of up to 1500 A/cm2. By this process, superconductor wires can be produced at shorter times and lower temperatures than the melt-texturing methods.