The properties of YBCO superconductors prepared by a new approach: the 'powder melting process'

A new method, termed the "powder melting process" (PMP), for the preparation of high J sub c YBCO superconductors has been developed. The YBCO conductors have been fabricated via a continuous melting and unidirectional solidification process using a precursor powders of Y sub 2 BaCuO sub 5 ((211) phase) and BaCuO as starting materials. The transport J sub c values of the samples, measured by a standard continuous DC four-probe method, exceed 10 800 A cm exp --2 at 77K and 1 T. A microstructural investigation indicated that the 123 grains are well oriented, and fine and dispersed 211 particles remained in the samples. YBCO conductors with various dimensions and shapes can be fabricated by the PMP method. This new approach has potential for the fabrication of oxide conductors with metal substrates, since its melting temperature is lower than that of other melting processes by approx 100 deg C. Graphs, Photomicrographs. 6 ref.--AA