Co0.35Mn0.65Fe2O4 magnetic particles: Preparation and kinetics research of thermal process of the precursor

Precursor of nanocrystalline Co0.35Mn0.65Fe2O4 was synthesized by solid-state reaction at low heat using CoSO4·7H2O, MnSO4·H2O, FeSO4·7H2O, and Na2C2O4 as raw materials. Nanocrystalline Co0.35Mn0.65Fe2O4 with spinel structure was obtained via calcining the precursor. The precursor and its calcined products were characterized using TG/DSC, FT-IR, XRD, SEM, EDS, and vibrating sample magnetometer. The results showed that the precursor dried at 353 K was a mixture consisted of CoC2O4·2H2O, MnC2O4·2H2O, and FeC2O4·2H2O. However, when the precursor was calcined at 623 K for 2 h, highly crystallization Co0.35Mn0.65Fe2O4 [space group R-3 m (166)] was obtained with a crystallite size of 22 nm. Magnetic characterization indicated that the specific saturation magnetization of Co0.35Mn0.65Fe2O4 obtained at 773 K was 66.14 Am2/kg. The thermal process of precursor experienced two steps, which involves the dehydration of the waters of crystallization at first, and then decomposition of Co0.35Mn0.65Fe2(C2O4)3 and formation of crystalline Co0.35Mn0.65Fe2O4 together. Based on the Kissinger equation, the values of the activation energy associated with the thermal processes of the precursor were determined to be 78 and 146 kJ/mol for the first and second thermal process steps, respectively.

Graphical abstractThe mono-dispersed Co0.35Mn0.65Fe2O4 nanoparticles were synthesized by the facile solid-state reaction at low heat. Magnetic characterization indicated that the specific saturation magnetization of Co0.35Mn0.65Fe2O4 obtained at 773 K was 66.14 Am2/kg.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Co-Mn ferrite nanoparticles were prepared by solid-state reaction at low heat. ► Magnetic properties are influenced by Co-Mn ferrite grain size. ► Kinetics of thermal process of the precursor was investigated for the first time.