Effect of fuel-to-oxidizer ratios on combustion mode and microstructure of Li2TiO3 nanoscale powders

A single phase Li2TiO3 powder has been fabricated through a facile solution combustion process, using citric acid as the fuel and corresponding nitrates as oxidants. The effect of fuel-to-oxidizer ratio (0.5-1.5) on the combustion process, the phase and microstructure of the products was investigated. By using different combinations of citric acid fuel and metal nitrates, the combustion mode could be controlled. When the fuel-to-oxidizer ratio is 0.75, an eruption combustion mode is realized. Thermodynamic analysis of the combustion reaction shows that as the fuel-to-oxidizer ratio increases, the adiabatic flame temperature during combustion also increases, but the measured maximum temperature decreases. The crystallite size of Li2TiO3 powders was calculated to be 18-36 nm at different combustion modes. The as-prepared Li2TiO3 powders exhibit excellent sinterability and can be sintered to 90.7% of the theoretical density at 800 °C. The grain size of the Li2TiO3 ceramics is around 800 nm.