Thick-film processing for Tl-oxide wire and tape

Thick-film processing techniques such as electrodeposition, electrophoresis, spray pyrolysis, and ink spraying offer promising and economic (<$10/kAm) approaches for fabricating high-temperature superconducting (HTS) wire or tape for the Tl-oxide superconductors. The performance of the Tl system exceeds that for the Bi-oxides and offers easier fabrication than YBCO. Scale up, however, may be difficult because of the need for open tape conductors with aligned microstructures. The Tl-oxides, moreover, offer the potential for operation at 77K in practical magnetic fields of 3-5 T, which is supported by measurements on the irreversibility behavior of the Tl-1223 single layer compound with Pb, Bi, and Sr substitution. Recent advances in the development of biaxial textured electrodeposited films on Ag coated single crystal substrates are discussed. This paper will review the merits for a near-term Tl-oxide based conductor for use in HTS electric power applications, currently under development, such as the transformer and transmission cable. Recent results for the buffer layer development that would provide an oriented ceramic layer or template on a flexible textured nickel substrate utilizing the "RABiTS" substrates developed by ORNL will then be discussed with a projection for the cost of a "long length" thick-film process using electrodeposition.