Bending Strain Characteristics of Critical Current in Double-Layered Bi-2223 Superconducting Tapes

The evaluation of reliability of HTS tapes is necessary for practical applications such as magnet, power cables, motors, SMES and HTS coils. The bending strain effect on the critical current, I c , in multifilamentary Bi-2223 HTS tapes have been investigated. Single and double layered tapes (for high current capacity) were subjected to thermal and pressurization cycles at pressurized liquid nitrogen (LN 2 ) up to 1 MPa. After the pressurization test, the subsequent occurrence of damage like ballooning due to the diffusion and expansion of LN 2 into the tapes were investigated and compared. The Bi-2223 tapes showed different I c degradation behavior depending upon the geometry and ratio of reinforcement to superconductor adopted.