Critical current density of rolled silver-sheathed Bi(2223) tapes

Silver-sheathed (Bi,Pb)₂Sr₂Ca₂Cu₃O_x (Bi(2223)) tapes were fabricated by the “oxide-powder-in-tube” technique. After the tapes were shaped and sintered, an additional cold rolling and a re-sintering were applied in order to enhance the critical current density J_c. The influence of the additional rolling conditions (roll diameter, number of passes, lubrication) on the J_c (77 K, 0 T) was made clear. The influence of the sintering conditions (temperature, heating rate) on J_c was also investigated. As for the rolling conditions, a small redundant shear deformation or a small contact angle leads to a good grain alignment, texturing, and a higher J_c value. As for the temperature of the first sintering, 1113 K is superior to 1118 K because of the volume fraction of the Bi(2223) phase.