Effects of excess NaClO4 on phases, size and magnetic properties of Ni–Zn ferrite powders prepared by combustion synthesis

Abstract Ni 0.4 Zn 0.6 Fe 2 O 4 powders were prepared by combustion synthesis with different amount of NaClO 4 . Phases, particle size and magnetic properties of the powders and annealed powders were systematically investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and vibrating sample magnetism (VSM). The excess content of NaClO 4 offered significant advantages with respect to the size, morphology and magnetic properties of the powders. After annealing, sub-micro ferrite spherical powders with spinel phase in a range of 500–800 nm can be obtained. With the increase of the NaClO 4 content, the saturation magnetization of the powders shows a maximum value at 68.8 emu/g when w =0.4, whereas the coercivity stayed nearly constant. The maximum saturation of annealed powders by combustion synthesis is much higher than the range reported in the literature.