Modified Combustion Synthesis of γ-Alumina Nano Powders

Abstract

Alumina nano powders have been prepared by a chemical method named combustion synthesis using new fuels. The effect of key factors on the synthesis of nanoparticles was studied and optimized using Taguchi L₁₆ (4⁵) array design. The products were characterized by XRD, TGA, EDX, FESEM, and TEM analyses. Results show that aluminum oxide powders had crystal sizes between 7.2 nm and 13 nm and specific surface areas between 21 m² g^-1 and 70 m² g^-1. It was found that there is a good linear correlation (R²=0.953) between crystallite size and specific surface area of the synthesized γ-alumina. The surface area of the sample prepared under optimum condition was 72 m² g^-1 and its average particle size measured by DLLS was 81 nm. The synthesis of γ-alumina was modified in order to achieve higher specific surface area (123 m² g^-1). A network of nano-fibers was successfully obtained by the modified route. The length and diameter of fibers were about 160 nm and 10 nm respectively.