Co1−xMgxFe2O4 magnetic particles: Preparation and kinetics research of thermal transformation of the precursor

Co1−xMgxFe2O4 precursor was synthesized by solid-state reaction at low temperatures using MgSO4·7H2O, CoSO4·7H2O, FeSO4·7H2O, and Na2C2O4 as raw materials. Co1−xMgxFe2O4 was obtained by calcining the precursor over 500 °C in air. The precursor and its calcined products were characterized by thermogravimetry and differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, and vibrating sample magnetometry. A high-crystallized Co1−xMgxFe2O4 with a cubic structure was obtained when the precursor was calcined at 500 °C in air for 2 h. The specific saturation magnetizations of Co1−xMgxFe2O4 depend on the calcination temperature and composition. The thermal transformation of the precursor from ambient temperature to 850 °C in air presented two steps. The values of the activation energies associated with the thermal transformation of CoC2O4-2FeC2O4·5.77H2O were determined based on the KAS equation.