Microstructure and Superconductivity of Bi-2223 Tape Prepared by Precursor Powders with Different Particle Sizes

Abstract

The effects of particle size of precursor powders on microstructure and superconductivity of Bi-2223 tape were investigated. Three kinds of precursor powders with different particle sizes (8, 2, <1 μm) were prepared by a spray pyrolysis method via adjusting the concentration of metal nitrates solution and ball milling. All powders were composed of Bi-2212, (Sr, Ca)xCuyOδ (AEC) and CuO phase after heat treatment. Results show that AEC phase dimension and content increase with decreasing of particle size of the precursor powders. However, the powder with an average particle size of 2 μm has the minimal dimension and content of CuO phase. Among the 37-filaments Bi-2223 tapes fabricated from the three kinds of precursor powders, the one from the powder with average particle size of 2 μm achieves the highest critical current (Ic), which also has the most (Bi, Pb)3Sr2Ca2CuOx (Pb-3221) and least AEC phase compared to other tapes. The particle size of the precursor powders mainly affects dimension and content of AEC and CuO phase, which further causes difference of Ic and non-superconducting phases in Bi-2223 tape.