Grain Orientation in High Tc Ceramic Superconductors
Molten salt or the ‘flux’ method has been a popular technique for growing cystals and particles with anisotropy morphology and has been utilized in this study. Preformed Ba2YCu3O7−x powders were reacted with the molten salts of Na, K, and Li belonging to the chloride, sulfate and iodide systems. The Ba2YCu3O7−x phase degraded when heat treated in the presence of these salt systems. Ba2YCu3O7−x powders prepared in the presence of NaCl-KC1 salt system does not appear feasible in the temperature range of 400°C–900°C. In another method the salt prepared grains were used as seed crystals in the formation of Ba2YCu3O7−x This method proved more promising permitting easy removal of the salts from BaY2CuO5 by water treatment and formation of phase pure 213 phase. X-ray diffraction analysis and Scanning Electron Microscopy were used to determine the compostion and morphology of the particles.
KeywordsMolten Salt Seed Crystal Salt System Molar Proportion Ceramic Superconductor
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