J_c-B Characteristics and Microstructure Dependence of J_c of High J_c Bi-based Superconducting Oxide Tapes

摘要

Bi-based 2223 superconducting tapes with high critical current densities were prepared by silver-sheathingmethod.The relationship between processing,microstructure and property was discussed.The results of criti-cal current density measurement at 77.7 K with different applied magnetic field are as follows:j_e=2.87×10~4A/cm^2(OT),J_e=4100 A/cm^2(H I.H||S.1T)and J_e-B characteristics are obviously improved withtemperature decreasing from 77 K to 4.2 K.Microstructtlre observations indicate that intermediate pressingwith subsequent heat-trcating could lower the porosity of superconductor inside the silver sheath,and reducethe amount and size of non-superconducting phases,leading phases,leading to the formation of a strong c-axis-orientedtexture,and the emergence of high dislocation density within the 2223 grains,and consequently the J(?)andJ_e-B characteritics were improved.