Fabrication and properties of Bi-2223 Ag-Au-Al alloy-sheathed tapes prepared by a controlled melting process

Bi-2223 Ag-Au-Al alloy-sheathed tapes with J(ct) (77 K, 0 T) up to similar to 20 kA cm(-2) were fabricated by a controlled melting (CM) process. It was found that the CM process is effective for eliminating weak links and improving the transport properties of Bi-2223 Ag-Au-Al alloy-sheathed tapes. The Bi-2223 phase decomposition is accelerated with the increase of melting temperature. Too high melting temperature may cause severe phase segregation, which is unrecoverable in the subsequent heat treatments. The effect of slow cooling rate on the transport properties is not obvious because of the low thermal conductivity of the Ag alloy sheath.