Property and Structure of YBa2Cu3Ox-Ag Composites Prepared from Nitrate Solutions

Mixtures of Y, Ba, Cu, and Ag nitrate aqueous solutions (nominal molten ratio of Y:Ba:Cu=1:2:3) were evaporated to dryness. The dried powders were codecomposed at 850°C in air, and sintered at 920°C for 20 h in O₂. The phases were only orthorhombic YBa₂Cu₃O_x and Ag. The bulk density, grain size, and critical current density (J_c) increased with increasing amount of Ag{≤q}5 wt%: for instance, up to 5.65 g/cm³, 30 μm, and 215 A/cm², respectively. The critical temperature (T_c(zero)) was about 91 K (with a width of 1-2 K) and insensitive to the amount of Ag{≤q}5%. With addition of Ag, the degradation in moisture was improved.