Phase Formation, Microstructure, and Densification of Yttrium-Doped Barium Zirconate Prepared by the Sonochemical Method

Spherical monodispersed yttrium-doped barium zirconate (BaY0.1Zr0.9O3; BYZ) particles were successfully prepared in single step without the requirement of calcination process by the sonochemical method in highly basic aqueous solution. The stoichiometric solution of BaCl(2 center dot)2H(2)O, ZrOCl2.8H(2)O, and YCl(4 center dot)6H(2)O was precipitated in a 20M NaOH under high-intensity ultrasonic irradiation (20kHz, 150W/cm(2)) for 15, 30, and 60min. As-prepared powders were identified by XRD, FT-IR, and Raman spectroscopy as cubic perovskite BYZ. The microstructure examined by SEM and TEM showed spherical-shaped BYZ particles formed by aggregation of primary nanocrystals, and this unique morphology was induced by the effects of the ultrasonication and the strong alkaline environment. BYZ powders prepared under ultrasonication for 60min had narrow-sized distribution with the average particle size of 267 +/- 26nm and the specific surface area of 40.2m(2)/g. BYZ ceramics sintered in the air at 1550 degrees C for 20h showed good densification (95%) and consisted of large grain size (7.67 +/- 2.79 mu m).