- September 2008
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- Nanometer-sized particles (1&-100 nm) are of considerable interest for a wide variety of applications, ranking from catalyst to luminescence ceramics, due to their unique and improved properties primarily determined by size, composition and structure. In this study, we report a simple, rapid aerosol decomposition process for the continuous synthesis of nanoparticles with adjustable sizes, narrow size distribution, high crystallinity and good stoichiometry.This paper presents the preparation and characterization of nanostructured spherical alumina particles (<500 nm sized) by low temperature aerosol synthesis for the application in MMCs reinforcement. Synthesis procedure includes aerosol formation ultrasonically from alumina nitrate water solution and its decomposition into a tubular flow reactor at 400 °C. Consequently, as-obtained particles are spherical, smooth, amorphous and in non-agglomerated state. The phase crystallization, either into gamma-Al2O3 or alfa-Al2O3 is promoted by additional thermal treatment ranging between 700 °C and 1300 °C. Detailed phase and structural analyses were carried out using X-ray powder diffraction (XRD), scanning electron microscopy (SEM/EDS) and analytical and high-resolution transmission electron microscopy (TEM/HRTEM).