Chapter 2.3: Lamination of Metals onto Bi-2223/Ag Wires

The technology, engineering science and motivation for laminating metal strips onto Bi-2223/Ag tapes are reviewed. The approach allows for the production of Bi-2223/Ag tape with high critical current (I_c) that can be laminated with many types of thin metal strips in order to improve axial stress, strain, bend, and surface indent tolerance as well as mitigation of cryogen penetration and thermal instability. Advances to attain target mechanical properties are enabled by an analytical model that identifies required modifications to internal stress, strain, and failure modes. The model also enables the selection of materials, architectures and process parameters for producing very robust tape. In a recent advance, laminated super alloy strips increased Bi-2223 tape axial stress tolerance from 120MPa to 540MPa, and axial strain tolerance from 0.25–0.4%, with a 30% reduction in whole wire current density from the added strip areas, but with no reduction in I_c.