IMPROVED SUPERCONDUCTOR TAPES AND COILS AND METHOD OF MANUFACTURE

摘要

A method of producing a high temperature long length coil of superconductor wire or tape having improved critical current densities by utilizing an in-line pressing operation to heal the microcracks in the tape or wire which where introduced in rolling and coiling operations. The material can be Bismuth-2223, Bismuth-2212, Thallium-1234 or any other high temperature superconducting material. In the case of the Bismuth-2223, an improved "powder-in-tube" processing operation is provided to utilize excess bismuth, calcium, and copper in the initial composition material, and forming a partially developed Bi-2223 phase in the precursor powder introduced into the silver tubes. The final product has a 90-100 % Bi-2223 phase with fine dispersions of secondary phases, to provide improved flux pinning thereby improving the critical current density of the material.