Synthesis and characterization of alumina nanopowders by combustion of nitrate-amino acid gels

Nanocrystalline alumina powders were synthesized by the combustion method using serine and asparagine as fuels. A screening design was conducted to determine how key process factors influence preparation of nanocrystalline powders. The screening design was utilized to rank effective factors on crystalline size of alumina powders. The product was characterized by XRD, BET, and SEM. Nanocrystalline gamma-alumina powders with crystal sizes between 3.95 nm and 6.71 nm and alpha-alumina powders with crystallite sizes between 22.73 nm and 33.92 nm have been obtained by the combustion synthesis. The specific surface areas of samples ranged between 22 m(2)/g and 75 in 2/g. Particle size distributions were determined by LLS and the average particle sizes of gamma-alumina powders after sonication were 37.42 nm and 79.32 nm. Results of statistical analysis illustrate that the fuel to oxidizer ratio is the most effective factor to decrease the average crystal size.