Current Applied Physics, Vol.19, No.4, 548-555, 2019
Combustion synthesis of nickel ferrite powders: Effect of NaClO4 content on their characteristics and magnetic properties
Magnetic powders of nickel ferrite (NiFe2O4) were successfully synthesized by combustion synthesis in air using iron (Fe), iron oxide (Fe2O3), and nickel oxide (NiO) as reactants and sodium perchlorate (NaClO4) as fuel (or oxidizing agent). The thermal behaviors were characterized using thermogravimetric analysis (TG) and differential thermal analysis (DSC). The as-combusted and final nickel ferrite powders were characterized in terms of chemical composition and morphology by X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) coupled with energy dispersive X-Ray spectroscopy (EDX). In addition, magnetic properties were examined by vibrating sample magnetometer (VSM). The results of TG/DSC analysis indicated that increasing the content of NaClO4 increased the exothermicity of combustion reaction. XRD indicated that the final nickel ferrite powders formed a single spinel NiFe2O4 phase when the amount of NaClO4 used was 0.08 or 0.10 mol. SEM revealed roughly octahedron particles with sizes in a sub-micrometer range ( similar to 500 nm). All final products exhibited soft magnetism and, synthesis that included 0.1 mol of NaClO4 produced pure NiFe2O4 powders that had a saturation magnetization (M-s) of 58.93 emu/g, which is higher than the reported value (55 emu/g) for the bulk product.