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

Abstract

Y-Ba-Cu-O (YBCO) precursor powder composed primarily of YBa 2 Cu 3 O 7−δ (Y-123) and Y 2 BaCuO 5 (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.

Preparation of doped precursor powders for the fabrication of large grain high temperature superconductors

“…This suggests that the majority of the as-produced powder is composed of agglomerates of much smaller particles. A similar agglomeration has been observed in calcined powders produced by spray drying [6]. Figs.…”

“…Fig. 3 shows an XRD trace for EDS produced powder, from which it can be seen to contain a mixture of un-reacted barium nitrate, amorphous Cu and RE oxides [6]. Fig.…”

“…Evaporative decomposition of solution (EDS), for example, has been used in the preparation of YBCO precursor powder containing Y-211 particles of less than lpm in diameter [6]. The related technique of spray drying has been applied in the production of Au-doped NdBCO.…”

HRTEM surface characterization of nanoscale solid‐state materials

“…Figure 3 shows a typical image of a spherical particle (¾500 nm in diameter) from (Y,Ba,Cu)-oxide precursor powder for synthesis of a high-quality high-temperature superconducting bulk specimen. 8 The darker image contrast in the surface areas, ¾20 nm in thickness, is indicative of a core-shell structure. In the same image there is a smaller particle, also showing the core-shell structure, with a diameter of ¾90 nm and a shell thickness of ¾5 nm.…”

The existence of a highly undercooled state during the formation of Y2BaCuO5in large grain Y–Ba–Cu–O superconductors

“…It is accepted widely that the size and distribution of Y-211 particles in the superconducting Y-123 phase matrix correlate directly with increased critical current density, J c , at low to moderate applied magnetic fields [2,3]. Numerous detailed studies of the composition and morphology of various rare earth (RE) RE-Ba-Cu-O [(RE)BCO] systems have been performed in order to optimize the properties of these materials for practical applications [4][5][6][7][8][9][10]. In particular, a homogeneous distribution of Y-211 particles in the Y-123 matrix is essential to achieve uniform superconducting properties throughout the bulk sample.…”