Carbon combustion synthesis and magnetic properties of cobalt ferrite nanoparticles

Cobalt ferrite Co[Fe.sub.2][O.sub.4] crystalline nanoparticles (50-100 nm) were produced by carbon combustion synthesis of oxides (CCSO). In this combustion synthesis process, the exothermic oxidation of carbon generates a thermal reaction wave that propagates through the solid reactants mixture of CoO and [Fe.sub.2][O.sub.3] converting it to cobalt ferrite. The extensive emission of C[O.sub.2] increased the porosity and friability of the product. The quenching front method combined with XRD and VSM characterization revealed that crystalline Co[Fe.sub.2][O.sub.4] particles formed in the early stage of the combustion, before the temperature reached its maximum. The maximum value of the coercivity of the quenched product within the front region was 940 Oe with a magnetization of 15 emu/g. The as-synthesized ferrites had hard magnetic properties with coercivity of 700 Oe and saturation magnetization of up to 47 emu/g. Index Terms--Carbon combustion, cobalt ferrites, nanostructured materials.