The effect of silver sheath on annealing texture of (Bi,Pb)(2)Sr2Ca2Cu3O10+x superconductor tapes

It is believed that, in BSCCO tapes, silver can promote the phase transformation from Bi2212 to Bi2223, but the effect of silver sheath on the texture formation of Bi2223 superconductors is not clearly understood. The present paper studies the effect of silver sheath on grain alignment of Bi2223 superconductors. Results indicate that the silver sheath serves as a wall that restricts the outward growth of the Bi compound, and also promotes the recrystallisation and growth of the a-b plane oriented Bi2223 grains. Based on the experimental results, the mechanisms of annealing texturing with the presence of silver sheath are discussed. This understanding can be used to control the microstructure of high temperature superconductors in an effort to improve their critical current density.