Fabrication and Properties of Ag-Ni Bimetallic Sheathed (Bi,Pb)-2223 Tapes

10-meter-long Ag-Ni bimetallic sheathed (Bi,Pb)-2223 tapes with outer nickel sheath and inner silver sheath have been successfully fabricated by the "Powder in tube" technique. Microstructure and phase evolution studies by means of SEM and XRD, as well as critical current density (J (c) ) measurements have been performed. It is found that the nickel sheath and dwell time in the first sintering process have great influences on the texture evolution, phase transformation and J (c) of the Bi-2223/Ag/Ni tapes. Mono-filament (Bi,Pb)-2223 tape with a J (c) of 6656 A cm(-2) and 61-filament tape with a J (c) of 12420 A cm(-2) are obtained. Although using composite bimetallic sheaths can reduce production costs and improve mechanical properties of the Bi-2223 tapes, the Bi-2223 content and J (c) of Bi-2223/Ag/Ni tapes are relatively lower than that of traditional Bi-2223/Ag tapes. Meanwhile, due to higher Bi-2223 content and better alignment of Bi-2223 grains, tapes with 61-filament have higher J (c) than mono-filament tapes.