Characteristics of coils wound with mono and multifilamentary Bi-2212/Ag from 4 to 80 K

Abstract

Many small coils wound with Bismuth based conductor have been manufactured with the Wind and React technique in solenoid shape. The construction of the coils has been integrated with an experimental investigation of the effect of curvature radius on the critical current and of the influence of different insulation materials (braids of quartz and of different ceramics) on the characteristics of the conductor and of the winding. A variety of conductor lay-out have been tested: Bi-2212/Ag with mono and multifilament design, pure silver or Ag-alloy as stabilizer. The influence of different heat treatment conditions-temperature, ramp rate and atmosphere-on the conductor and on the coils performances is presented. The performances of the coils, wound with conductor length from 2 to 36 m, are compared with respect to the short sample critical currents at 4.2 and 77 K and the measurements of the irreversibility lines are discussed. In few coils I/sub c/ is 50% of the short sample value, reaching 80% in the best case.