The Preparation Of High Bs And Low Loss MnZn Ferrite Material

High saturation magnetization-Low loss Mn Zn power ferrites were prepared by conventional oxide ceramic process. It mainly studied the master recipe selection, pre-sintering, doped and the sintering process on the microstructure and magnetic properties of the High saturation magnetization-low loss Mn Zn Ferrites. The main objectives: initial permeability μi = 2200±25%; Bs≥540 m T(T = 25 ℃); Bs≥450 m T(T = 100 ℃); Pev≤320 kw / m3(T = 100 ℃);The study of the main recipe found that for High saturation magnetization –low loss Mn Zn ferrite. The Mn3O4 was selected as 23.4 wt%, with the increase Pts.wt of the Fe2O3, the initial permeability, sintered density, saturation magnetization is first increased and then decreased, the material loss decreased first and then increased. The study of pre-sintering temperature have found that the material property was not as the lower temperature and the higher activity of materials as the better of performance. Sintered density, initial permeability, saturation magnetization are increased with the pre-sintering temperature increased first and then decreased. Loss is in one of the most suitable formulation process of pre-sintering temperature obtained a good magnetic properties. It is found on the doping research. With the increase of the doping amount of Ni O, the density increased, the permeability decreased, the point of low loss moves to high temperature. Saturation magnetization first increases and then decreases Appropriate with Co O was added, it can make the Lowest loss point move to high temperature while the lowest loss did not significantly increase. Co O-Ni O dopant can improve the permeability. Ca CO3 and Si O2 composite doping, a barrier layer is formed on the grain boundaries., reduce the eddy current loss of material. It is found that for a formula, Ca CO3 and Si O2 has an optimal proportion. Whether Ca CO3 excess or Si O2 excess It will cause the deterioration of material properties. The proper V2O5 doping can form liquid phase sintering, it contributes to grain growth. increase the permeability of materials and sintered density, improve the saturation magnetization. Excess of V2O5 doped will make the material crystallization anomaly. resulting in deterioration of the material properties. Study of Nb2O5 doped found, Due to the high melting point of Nb2O5, Generally does not have solid phase reaction with the ferrites. mainly used in the grain boundaries to obstruction grain growth. With the increase of Nb2O5 doped, material loss decreased firstly, with the increased to the amount of doping, will cause the discontinuous grain growth, magnetic properties of material deteriorated. The study of Zr O2 doped found that with the Zr O2 increases, promoted the uniformity of the material, reduces the porosity and loss reduction. As the doping increases, the rapid grain growth, stomatal was involved in the grain, deterioration of the magnetic properties. With the study of the sintering process of sintering temperature and holding atmosphere found that as the sintering temperature increased the sintering density increased, and the saturation magnetization increases, the loss decreased firstly and then increased. Insulation stage, with the increase of the oxygen content, the minimum loss point of the material has a moving direction of high temperature trend. Low oxygen concentration promotes the decomposition of Zn O makes the material saturation magnetization decrease. For the High saturation magnetization-Low loss Mn Zn power ferrites there is an optimum sintering temperature and holding the oxygen content.