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 tran sformation from Bi2212 to Bi2223, but the effect of silver sheath on t he texture formation of Bi2223 superconductors is not clearly understo od. The present paper studies the effect of silver sheath on grain ali gnment of Bi2223 superconductors. Results indicate that the silver she ath serves as a wall that restricts the outward growth of the Bi compo und, and also promotes the recrystallisation and growth of the a-b pla ne oriented Bi2223 grains. Based on the experimental results, the mech anisms of annealing texturing with the presence of silver sheath are d iscussed. This understanding can be used to control the microstructure of high temperature superconductors in an effort to improve their cri tical current density.