Bending Damage Evolution and Its Influence on Critical Current and N-Value of Bi2223/Ag Superconducting Composite Tape

Abstract

Bending behavior of Bi2223/Ag superconducting composite tapes, and the influence of the bending damages on critical superconducting current Ic and n-value that is a measure for the sharpness of the transition from super- to normal conduction, were studied. Following damages, responsible to the reduction in critical current at high bending strains, were observed. (i) Transverse and (ii) longitudinal crackings of the filaments, (iii) interfacial debonding between filaments and silver, and (iv) buckling in compression side. The damage of the filaments arose first locally, resulting in a reduction of the Ic and n-value in the corresponding local portion. The overall Ic and n-values were determined by such a local portion. With increasing strain, the damage of the other portions arose successively, resulting in loss of superconductivity in all portions.