The study of combustion synthesis of fine-particle γ-lithium aluminate

Fine-particle gamma-lithium aluminate has been prepared by the combustion of mixtures of the metal nitrates, M(NO3)(x) ( M = Li, Al) as oxidizers and urea and citric acid as fuels, at low temperature and short reaction time. The combustion products were identified from X-ray powder diffraction (XRD) patterns, scanning electron microscopy (SEM), and pore size distribution measurements. As the total composition of oxidizing and reducing elements of the reactants leave related to the thermochemistry of the system, a simple method of calculating the elemental stoichiometric coefficient was introduced. The physical significance of such a correlation based on thermochemical reasoning was investigated. It was found that a significant improvement was achieved in the reactant mixture with a molar ratio of urea: citric acid = 9: 1. An improvement in the combustion synthesis of gamma-lithium aluminate is due to the formation of an activated complex of the fuel with the corresponding oxidizer. (C) 2003 Kluwer Academic Publishers.