PROCESSING OF SINGLE-PHASE CERAMIC YBACUO 123 SUPERCONDUCTOR BY HOT PRESSING.

POLYCRYSTALLINE SAMPLES OF HIGH-TEMPERATURE SUPERCONDUCTING YBACUO 123, EXHIBIT: (1) DENSITIES UP TO 82% OF THE THEORETICAL VALUE ; (2) A SHARP PHASE TRANSITION BETWEEN THE NORMAL AND SUPERCONDUCTING STATES AT 91.6 K ; (3) A REDUCED DEPENDENCE ON THERMAL CYCLING EFFECTS AND ON EXCITATION CURRENTS IN RESISTIVITY MEASUREMENTS ; AND (4) A REDUCTION IN SURFACE DETERIORATION DUE TO WATER, AIR, AND ACID ATTACK. THE HOT-PRESSED SAMPLES SUPPORTED CURRENT DENSITIES AT LEAST 2 ORDERS OF MAGNITUDE GREATER THAN THOSE FOUND IN COLD-PRESSED SAMPLES MEASURED UNDER SIMILAR CONDITIONS.