Glycine-nitrate solution combustion synthesis of lithium zirconate: Effect of fuel-to oxidant ratio on phase, microstructure and sintering

Abstract Pure monoclinic lithium zirconate (Li2ZrO3) powder was synthesized by solution combustion route using glycine as fuel and nitrates as oxidants. Effect of fuel-to-oxidizer ratio (φ = 0.5–1.25) on synthesis condition, phase, powder morphology, sintering and thermodynamic aspects was systematically investigated. Thermodynamic analysis reveals; mode of combustion, adiabatic flame temperature, amount of gases and powder characteristics can be controlled by adjusting φ. The crystallite size of Li2ZrO3 powder was in the range of 18–40 nm. The powders consist of micrometric soft-agglomerates of irregular flake shape particles. The residual Li2O in Li2ZrO3 powder was found to be in the range 155–469 μg/g. The Li2ZrO3 powder synthesized by present method shows significantly enhanced sinter-ability as compared to conventional solid-state method. The Li2ZrO3 pellets were sintered close to 98% of T.D. at 1000 °C with grain size 1–2 μm. Increase of sintering temperature to 1050 °C results abnormal grain growth with large number of closed pores.