Influence of extra magnesium on the Nb-B interface and superconducting properties of MgB2/Nb tapes
Résumé
Effects of extra Mg additions on the Nb-B interface and the superconducting properties of mono-core MgB2/Nb/Cu tapes were investigated. Four Mg1+xB2/Nb/Cu tape samples were prepared by standard in situ PIT method (x = 0, 0.03, 0.05, 0.10). For maintaining the superconducting properties, the extra Mg is supposed to prevent the Nb-B diffusion, which is the main cause of decline in superconducting properties of Nb sheathed MgB2 tapes. And it has been proved that a suitable amount of Mg addition did play a positive role in slowing down the Nb-B diffusion to some degree on one hand. And the superconducting properties also show some improvements. While over sufficient Mg addition would accelerate the formation of the Nb-B diffusion layer on the other hand. According to the experimental results, the suitable amount of Mg addition should be between x = 0.03 and 0.05 depending on the different sintering temperatures.