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

Abstract

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. Monofilament (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.

Bi-2223 grain growth in Ag/Ni composite-sheathed tapes sintered at different oxygen partial pressures

“…Bi 1.8 Pb 0.33 Sr 1.87 Ca 2.0 Cu 3.0 O 10 + δ (Bi‐2223) material is a typical ceramic material. Ag/Ni composite‐sheathed Bi‐2223 (Bi‐2223/Ag/Ni) superconducting tapes have been fabricated successfully by Grivel and Chen et al in recent years. Owing to the advanced Ag/Ni composite‐sheathed technique, Bi‐2223/Ag/Ni tapes that have lower cost and higher strength show great superiority relative to traditional Bi‐2223/Ag tapes.…”

“…Owing to the advanced Ag/Ni composite‐sheathed technique, Bi‐2223/Ag/Ni tapes that have lower cost and higher strength show great superiority relative to traditional Bi‐2223/Ag tapes. However, the maximal critical current density ( J c ) of Bi‐2223/Ag/Ni superconducting tapes has only reached 35,000 A/cm 2 , which is far from enough to satisfy the practical demand . Practical applications expect more investments to greatly improve the transport properties of Bi‐2223/Ag/Ni tapes.…”

“…The achievements based on traditional ways are also remarkable. Many reports indicate that phase formation and microstructure evolution in Bi‐2223/Ag/Ni tapes have some different behaviors comparing with that in Bi‐2223/Ag tapes . Exploration on grain growth under different sintering conditions in Bi‐2223/Ag/Ni tapes is a very important precondition for designing an optimized microstructure‐controlling process.…”

Effects of Ni Sheath on the Microstructure and Properties of BSCCO-2223 Tapes

“…Soft Ag can't provide enough mechanical properties to tapes [2,3]. Since, the mechanical property strengthened Ag/Ni BSCCO-2223 (Bi-2223/Ag/Ni) tapes have attracted many attentions after its appearance [4,5]. A maximal critical current density (J c ), 35000 A/cm 2 , has been reached in Bi-2223/Ag/Ni tapes which is already equal to that in Bi-2223/Ag tapes nowadays [5].…”

“…Since, the mechanical property strengthened Ag/Ni BSCCO-2223 (Bi-2223/Ag/Ni) tapes have attracted many attentions after its appearance [4,5]. A maximal critical current density (J c ), 35000 A/cm 2 , has been reached in Bi-2223/Ag/Ni tapes which is already equal to that in Bi-2223/Ag tapes nowadays [5]. Bi-2223/Ag/Ni tapes show great superiority in practical applications for its lower cost and higher strength.…”