Abstract
An experiment was carried out to investigate the effect of MnO substitution, mole ratio n { = Fe3+/(Co2++Ni2++Mn2+)}, reaction temperature, and concentration of alkali on the magnetic and physical properties of Co-Ni-Mn ferrite prepared by the chemical coprecipitation method without post-annealing. The chemical coprecipitation compositions were chosen according to the formula (CoO)0.5(NiO)0.5-x(MnO)x·n/2(Fe2O3), where x varied between 0 and 0.5 and n varied between 1.80 and 2.00. To remove the superparamagnetic substance, the coprecipitation fine particles were etched with dilute sulfuric acid. As a result, in the (CoO)0.5(NiO)0.3(MnO)0.2·1.95/2(Fe2O3) composition, when the reaction temperature and excess NaOH were 60°C and 0.5 mol, the following magnetic and physical properties were obtained: saturation magnetization σs = 79.77×10-6 Wb·m/kg, residual magnetization σr = 47.38×10-6 Wb·m/kg, coercivity HcJ = 184 kA/m, and average particle size D = 19.61 nm.
