PREPARATION OF SUBMICROMETER SPHERICAL OXIDE POWDERS AND FIBERS BY THERMAL SPRAY DECOMPOSITION USING AN ULTRASONIC MIST ATOMIZER

Highly sinterable submicrometre spherical oxide powders and fibres have been prepared by the thermal spray decomposition of an aqueous solution using an ultrasonic atomiser. The concentration of aqueous solution, carrier-gas flow rate, and decomposition temperature influenced the particle size and particle morphology. Powder X-ray diffraction patterns of oxide powders showed crystalline phases. Energy dispersive spectroscopy analysis for YBa2Cu3O7-x (YBCO) and polycrystalline tetragonal zirconia (3Y-TZP) particles showed little compositional fluctuation. The resistivity of YBCO ceramics was measured by the four-probe method, resulting in superconduction at T(c) = 90 K (onset), and 88 K (end).