POWDER-IN-TUBE-PROCESSED MULTIFILAMENTARY BI-(2223) TAPES WITH SILVER-ALLOY SHEATHS

Superconducting Bi-(2323) multifilamentary tapes with Ag100-xYx alloy sheaths, with Y=Cu, Mn and Pd, were made by the oxide-powder-in-tube t echnique. All resistivities of the Ag alloy sheaths exceed that of the pure Ag sheath by at least a factor of 2. The maximum resistivity was achieved for Ag99Pd1 with rho(77K)=1.3 mu Omega cm. Tapes sheathed by Ag90Cu10 exceed the critical current density, Jc, of pure Ag sheathed ones. J(C) up to 26 kA/cm(2) were achieved by pressing sheathed tapes during the thermo-mechanical-treatment, TMT. For thinner Ag90Cu10 she athed tapes up to 31 kA/cm(2) were obtained employing flat rolling dur ing TMT. Measured irreversibility lines of thin and thicker tapes with comparable J(C) Suggest, that thicker tapes have a larger pinning str ength and a better grain texture bit thinner ones better grain-to-grai n connectivity.