Effect of grinding method on the precursor powder of Bi2223 and properties of strip

In this paper, the two kinds of precursor powders of BiPb2212 and CaCuO₂ were prepared by double powder method and an improved coprecipitation method, and then the BiPb2212 powders were fabricated by mechanical grinding and hand grinding. The BiPb2212 powders and CaCuO₂ powders were prepared by two kinds of grinding methods mixed with a certain proportion of grinding, the Bi2223 superconducting tape with 37 filaments were prepared by removing the carbon, filling tube and annealing. The XRD analysis, SEM observation, laser particle size analysis and the tap density test of the precursor BiPb2212 powders were carried out respectively by mechanical grinding and hand-grinding. The results showed that the phase composition, microstructure, particle size distribution and tube density detection were all significant differences by using two kinds of grinding methods. Finally, the superconductivity test of the treated strip results show that the critical current from the field for the Bi2223 multi-core strip at 77K is improved from 86A (hand-grinding method) to 127A( mechanical grinding method). Therefore, the Bi2223 precursor powder by using mechanical grinding method is more conducive to obtain high-performance.