Characterization of freeze-dried powders prepared by alkoxide route for YBCO superconductors

Freeze-drying is a practical method of synthesizing powders for superconductors, because freeze-dried powders are fine, porous and homogeneous. In our previous studies, we had prepared the fine powders for the YBCO superconductor using freeze-drying of the suspensions obtained by coprecipitation of carbonates. These powders had been confirmed to be good materials for superconductors. Furthermore, YBCO superconductors had been produced from these powders, and had shown good electric and magnetic properties. In this paper, we report on complex oxides for YBCO superconductor using freeze-drying of suspensions obtained by simultaneous hydrolysis of metal isopropoxides. These powders were also confirmed to be useful for YBCO superconductors from the results of characterizations, such as elementary analyses by ICPS, EPMA images, SEM micrographs, DTA and TGA analyses.