Enhanced flux pinning of Bi-2223/Ar tapes with nano-MgO particles addition

For the purpose of producing flux pinning centers, nano-MgO particles have been introduced into (Bi,Pb)2)Sr2Ca2Cu3Ox silver-sheathed (hereafter: Bi-2223/Ag) tapes fabricated by the Rod-In-Tube (RIT) process. It is found that transport critical current density (Jc) of samples doped with nano-MgO particles is higher than that of undoped samples by a factor of 1.2 in zero applied field and about 1.4 in a magnetic field range from 0.1 to 1 T at 77 K. Well-dispersed MgO particles can be observed by SEM. These results indicate that the introduction of nano-MgO particles can effectively improve the flux pinning ability and has a little detrimental effect on the Bi-2223 superconducting matrix

Improvement of the phase formation and superconductivity of the (Bi,Pb)2Sr2Ca2Cu3Ox silver sheathed tapes with B2O3 addition

In (Bi,Pb)2Sr2Ca2Cu3Ox silver-sheathed (Bi2223/Ag) tapes, melted liquid phase plays an important role to form the Bi2223 phase. We have added a small amount of B2O3 into Bi2223/Ag tapes to assist in inducing melted phase because B2O3 has a melting point (460°C) much lower than the general sintering temperature of the tapes, and studied the influence of B2O3 doping on the microstructure and critical current density (Jc) of Bi2223/Ag tapes. The results show that B2O3 doping is really effective to result in the faster growth and better alignment of the Bi2223 grains in the superconducting core and improve the magnetic field dependence of the Jc value