The effect of WB additions upon the microstructure and superconducting properties of Fe-sheathed MgB2 tapes was investigated. The microstructure was not influenced appreciably by the additions, whereas the superconducting properties changed. Even by a 5mol% addition, TC decreased by about 0.5K. However, the field dependence of the inductive critical current density, JCi, became smaller with the increase in the amount of addition, suggesting that pinning centers effective in a high-field region were possibly introduced. The transport critical current density, JCt, at 4.2K increased about twice by the 5mol% addition and reached 15 and 5kA/cm2 at 8 and 10T, respectively.

Enhancement of Critical Current Density of in situ Processed MgB2 Tapes by WB Addition. H.Fujii, K.Togano, H.Kumakura: Superconductor Science and Technology, 2003, 16, 432-6