2000 Volume 18 Issue 3 Pages 468-473
There are few reports on the bonding process for Bi-2223 multifilament wires in Bi-family superconducting wires because of the difficulty of bonding them directly. Using diffusion bonding process with interlayer materials, Bi-2223 multifilament wires are expected to be bonded at no resistance of the joint.
The aim of this study is to develop the interlayer materials that have the better superconductivity characteristics. The superconducting powder with a cation ratio of Bi : Pb : Sr :Ca:Cu=1.8:0.4:2:2:3 was mixed with various amounts of Ag2 O powder. Then the powder was cold-pressed with various pressures into disk-shaped pellets. The compounds were sintered at various temperatures in air for 100 h. The most suitable treatment conditions were investigated from the viewpoint of superconductivity, composition and structure.
The most suitable interlayer material was cold-pressed using the compounds with 2 mass% Ag2O powder and heated under heating conditions of 847°C, 100 h in air subsequently. Critical current density increased with an increase in the ratio of 2223 Phase and the density of the interlayer materials. There was a suitable heating temperature to increase the ratio of 2223 Phase. The density of the interlayer materials was increased by the addition of Ag2O filling up the voids of interlayer materials.