Bending strain dependence of the critical current degradation behavior in externally-reinforced Bi-2223 tapes with different hermeticity under pressurized liquid nitrogen

외부 보강된 Bi-2223테이프의 가압 $LN_2$하에서 임계전류 열화거동의 굽힘변형률 의존성

The $I_c$ degradation behaviors of externally-reinforced Bi-2223 superconducting tapes under pressurized liquid nitrogen were investigated. Tapes with different thickness of reinforcement layers were compared and the results showed that when the bending strain was calculated at the outer surface, the tape with the thicker reinforcement showed a better bending strain tolerance of $I_c$, but when the bending strain was calculated at the outermost filament, the $I_c$ degradation behavior became identical for all tapes. $I_{c0}$ decreased with the increase of applied pressure. After depressurization to atmospheric pressure from 1 MPa, the $I_c$ was completely recovered to its initial values. Ballooning occurred after a thermal cycle.