Combustion synthesis of cobalt ferrite nanoparticles—Influence of fuel to oxidizer ratio

The effect of fuel characteristics on the processing of nano-sized cobalt ferrite fine powders by the combustion technique is reported. By using different combinations of glycine fuel and metal nitrates, the adiabatic flame temperature (Tad) of the process as well as product characteristics could be controlled easily. Thermodynamic modelling of the combustion reaction shows that as the fuel-to-oxidant ratio increases, the amount of gases produced and adiabatic flame temperatures also increases. The powders obtained by combustion were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermo gravimetric analysis and differential thermal analysis (TG–DTA), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM) measurements. The particle size of phase pure cobalt ferrite nanoparticles was found to be <40 nm in this investigation. The effects of glycine addition with stoichiometric (ϕ = 1), fuel lean (ϕ < 1) and fuel rich (ϕ > 1) precursor batches were investigated separately.

► Phase stability, morphology, microstructure and crystallite size depends on glycine to nitrate molar ratio.
► Amount of gas produced and adiabatic flame temperature influenced by glycine to nitrate molar ratio.
► Crystallite size of the nanoparticles linearly depends on flame temperature.