Effect of Fuel to oxidizer ratio on physical properties of ZnO nano powders synthesized by solution combustion method

ZnO nano crystallite particles synthesized by solution combustion method. Glycine, urea, citric acid, hydrazine and hexamine were used separately as fuel in each experiment. The effect of different ratios of fuel to oxidizers... [ view full abstract ]

ZnO nano crystallite particles synthesized by solution combustion method. Glycine, urea, citric acid, hydrazine and hexamine were used separately as fuel in each experiment. The effect of different ratios of fuel to oxidizers (F/O= 0.75, 1, 1.25) on physical properties of synthesized powders were also studied. Crystallite size of nano powders were characterized by refinement and scherrer method. The obtained results showed that crystallite size was in the range of 20 to 50 nm based on the kind of fuel. Particles which were synthesized in the higher amount of fuel (F/O = 1.25) had higher crystallite size. XRD results showed that all sample are pure ZnO and the kind of fuel and F/O ratios didn’t affect the purity of samples. Scanning electron microscopy (SEM) was used to analyze the morphology of obtained particles. SEM results showed the irregular morphology of synthesized powders independent of kind of fuel. Magnetization saturation of ZnO particles were measured by VSM method. Although published results showed that ZnO particles have diamagnetic properties, our results indicate that, regarding the kind of fuel, ZnO particles were paramagnetic or even ferromagnetic. The magnetization saturation of synthesized particles had the maximum amount of 0.3 emg/gr. Optical band gap of produced particles were also studied Uv spectroscopy method. The results indicated that particles which showed magnetization, had unusual Eg values which implyed that the producing method could insert crystalline defect in structure of synthesized powders.