PREPARATION AND CHARACTERIZATION OF SUBMICRON SPHERICAL-PARTICLES OF AL2O3, SIO2 AND MULLITE

Nebulized spray pyrolysis of metal-organic precursors has been employe d to prepare sub-micron spherical particles of Al2O3, SiO2 and mullite . This process ensures complete decomposition of the precursors at rel atively low temperatures. The particle size, shape and structure have been examined by scanning and transmission electron microscopy as well as X-ray diffraction. The particles as prepared are amorphous and are hollow agglomerates (0.2-0.8 mu m in diameter). After heating to high er temperatures, the ultimate size of the crystalline particles turns out to be even smaller (30 nm or less in diameter). (C) 1998 Elsevier Science S.A. All rights reserved.