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

The effect of adding fully reacted 2223 particles in the precursor powder o n 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 adde d to the precursor powder consisting of mostly 2212 and calcium plumbate ph ases. The tapes seeded with 2223 particles showed a relatively high J(c) in a short annealing time without a mechanical deformation steps. The existen ce of 2223 particles in the precursor powder resulted in a smaller grain si ze 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 tran sformation kinetics indicates that a two dimensional nucleation and growth process is the most plausible mechanism for 2223 phase formation. For the t apes containing seed particles, the formation rate of 2223 phase was found to be controlled by the diffusion of material, while the formation of nucle i controlled the 2223 formation for the tape containing no seed particles.