Preparation Of Mn-Zn Ferrite By Chemical Coprecipitation Method And Its Magnetic Properties

Manganese zinc ferrite is a kind of magnetic excellent soft magnetic materials, which have been widely applied in modern new and high technology industries. Based on the ZnSO4·7H2O, FeSO4·7H2O, MnSO4·H2O as raw materials, ammonium oxalate (NH4)2C2O4·H2O as precipitant, this paper prepared Mn-Zn ferrite precursor powder by the chemical co-precipitation, and finally prepared samples of manganese zinc ferrite after the process of molding and sintering. The research content as follows: first, formation process of manganese zinc ferrite with spinel structure; second, influence of PH, pre-sintering temperature, sintering temperature on the microstructure and magnetic property of the Mn-zinc ferrite. Third, the effects of manganese zinc ferrite magnetic permeability due to doping the mass fraction of0.25%of TiO2.This paper used SEM, XRD to analysis the microstructure such as grain size and boundary and magnetic property of the Mn-Zn ferrite. Studies have shown followed: first, Manganese zinc ferrite with spinel structure has been formed in the process of pre-sintering, fully formed in the sintering process; second, Comparing with the SEM images of manganese zinc ferrite with different PH dealing, we found that manganese zinc ferrite microstructure is better than that of the other conditions, and also found that density of Zinc ferrite is about5.17g/cm3its permeability, the resistivity is relatively high when the mixture of the PH value of7. So, the PH value of7is ideal PH value for the preparation of high permeability manganese zinc ferrite. Third, comparing the SEM images under the different pre-sintering temperature for preparing manganese zinc ferrite, we found pre-sintering temperature have on influence on manganese zinc ferrite grain size, except for grain boundary definition and porosity. The density of manganese zinc ferrite is about5.17g/cm3and manganese zinc ferrite magnetic permeability and resistivity is higher than other temperature when pre-sintering temperature is800℃. So, High permeability of manganese zinc ferrite ideal pre-sintering temperature should be800℃. Fourth, comparing with the microstructure p of manganese zinc ferrite under different sintering temperature, we found that the sintering temperature of manganese zinc ferrite has certain influence on grain size, grain boundary definition and porosity. When the sintering temperature is1250℃, the grain size of the sample size uniformity, grain boundary and microstructure are ideal by SEM observation and magnetic permeability and resistivity also reached the maximum. High permeability of manganese zinc ferrite ideal sintering temperature should be1250℃. Fifth, we found permeability changes along with frequency decline rapidly. In order to enhance the stability of permeability along with frequency, the mass fraction of0.25%of TiO2was added to manganese zinc ferrite, results showed that certain amount of TiO2can improve stability of permeability change with frequency.