ULTRASOUND EFFECTS ON VARIOUS OXIDES AND CERAMICS - MACROSCOPIC AND MICROSCOPIC ANALYSES

The sonochemistry of a heterogeneous medium such as a liquid/ solid powder has been studied for various oxides (lead, manganese, aluminum, rare earth elements, silicon, titanium, and chromium) and ceramics (superconductor and titanium-yttrium compounds). The chemical transformations that occur during ultrasound treatments appear to differ from one material to another. The most important results relate the leaching of Pb3O4 which forms the dioxide in dilute acetic acid; and the formation of alpha-Al2O3, and Al(OH)(3) from the eta-Al2O3 form. It has been established that ultrasound treatments decrease the grain size and smooth small particles. (C) 1995 Academic Press, Inc.