Properties of Y-Ba-Cu-O powder prepared by evaporative decomposition of solution for melt-processed bulk ceramics

Y-Ba-Cu-O (YBCO) precursor powder composed primarily of YBa₂Cu₃O_7-δ (Y-123) and Y₂BaCuO₅ (Y-211) containing 0.1 w/w% Pt has been prepared by the evaporative decomposition of solution (EDS) and subsequent calcination for the fabrication of bulk melt-processed ceramics. The decomposition process in the as-produced powder and the formation of the Y-123 and Y-211 phases have been studied in detail using differential thermal analysis and powder x-ray diffractometry. The morphology, microstructure and particle size distribution of the powder has been investigated using scanning electron microscopy, transmission electron microscopy and particle size analysis, and the powder has been found to contain a significant proportion of sub-micrometre-sized particles. Samples fabricated by seeded melt growth using the EDS-prepared powder have been observed to exhibit a finer distribution of the Y-211 phase than is typically obtained in similar samples prepared via a mixed oxide route. This provides direct evidence of the suitability of EDS precursor powder for the fabrication of large-grain, high-J_c melt-processed YBCO monoliths.