Solution Combustion Synthesis of Fe3O4 Powders Using Mixture of CTAB and Citric Acid Fuels

Magnetite (Fe3O4) powders were synthesized by solution combustion method using a mixture of cetyltrimethylammonium bromide (CTAB) and citric acid fuels at various fuel to oxidant ratios (ϕ = 0.5, 1, 1.5, and 2). Phase evolution investigated by x-ray diffraction method showed single-phase Fe3O4 powders were only formed at ϕ = 1 using mixture of fuels, while impurity α-Fe2O3 phase together with magnetite phase was completely disappeared at ϕ = 2 for CTAB fuel alone. The specific surface area and porous structures of the as-combusted Fe3O4 powders were characterized by N2 adsorption-desorption isotherms and scanning electron microscopy techniques, respectively. The specific surface area using the mixture of fuels (37 m2/g) was higher than that of CTAB fuel alone (32 m2/g). Magnetic properties of the as-combusted powders were studied by vibration sample magnetometry method. The highest saturation magnetization of 83 emu/g was achieved by mixture of fuels at ϕ = 1, due to the high purity and large particle size.