Fabrication of Bi2Sr2Ca1Cu2Ox superconductor using metallic substrate tapeclad with Ag

With the intentions of the reduction of material cost and the improvement o f mechanical properties, Ag/Ni and Ag/Stainless Steel (SUS) clad tapes were prepared as substrate materials for the fabrication of Bi2Sr2Ca1Cu2Ox (Bi- 2212) superconducting tape. Bi-2212 formed on the Ag/Ni clad tape with a 10 mum Ag layer thickness showed good superconducting properties of T-c = 88 K and J(c) (4.2 K, 10 T) = 1.7 x 10(5) A/cm(2), comparable to those of Bi-2 212 tape fabricated using pure Ag tape. However, Bi-2212 formed on the Ag/N i clad tape with a 5 mum Ag layer thickness showed deteriorated properties due to the transfer of Cu and Ni across the Ag layer. The Ag/SUS clad tape did not work as a substrate material, because the Ag layer was eroded, form ing many holes, and hence could not prevent a severe reaction between Bi-22 12 and SUS. The J(c) of the Bi-2212/Ag/Ni tape started to degrade at epsilo n = 0.2-0.3% in the bending test. A tensile test indicated that the Ag/Ni c lad tape had about three times larger yield strength than pure Ag tape. Fro m these results, it is expected that the Bi-2212/Ag/Ni tape has a much impr oved stress tolerance over the conventional Bi-2212/Ag tape, (C) 2001 Elsev ier Science B.V. All rights reserved.