Properties of Ag/Bi-2223 superconducting tapes seeded with fully reacted 2223 particles

Abstract

The effect of adding fully reacted 2223 particles in the precursor powder on the final properties of Ag/Bi-2223 tapes has been investigated. Different amounts of fully reacted 2223 particles ranging from 0 to 10 wt% were added to the precursor powder consisting of mostly 2212 and calcium plumbate phases. The tapes seeded with 2223 particles showed a relatively high in a short annealing time without a mechanical deformation steps. The existence of 2223 particles in the precursor powder resulted in a smaller grain size and showed no appreciable incubation period and a faster transformation rate in an isothermal annealing experiment compared to the tape containing no seed particles. A detailed analysis of the microstructure and phase transformation kinetics indicates that a two dimensional nucleation and growth process is the most plausible mechanism for 2223 phase formation. For the tapes containing seed particles, the formation rate of 2223 phase was found to be controlled by the diffusion of material, while the formation of nuclei controlled the 2223 formation for the tape containing no seed particles.