Preparation And Electromagnetic Properties Of MnZn Ferrite FeSiAl Composite

Soft magnetic material is the basic materials for the development of electronic information.It is widely used in aerospace,industrial and commercial electronic components,such as electron beam deflection coils,radio chokes,high and low frequency transformers,industrial mode inductors,LC filters,EMI shielding rings and electronic ballasts,etc.In order to adapt to the development of electronic information,the devices must be low-loss,light-weight,miniaturized,chip-shaped,modularized,high-reliability,and long-term working stability.This is significant for exploiting Mn Zn ferrite materials with high permeability and low power loss via the optimization of traditional oxide ceramic technology and new technology.Meanwhile,it can help study high-performance Mn Zn ferrite composite materials.In this paper,Mn Zn ferrites were prepared by oxide ceramic technology and mechanochemical method,respectively.The effects of the main components of Mn Zn ferrite and the particle size distribution of secondary grinding powder on the magnetic properties were studied deeply,and then the optimal sintering temperature was found out.Hence,the effect of different content of Mn Zn ferrite on the electromagnetic properties of Mn Zn ferrite Fe Si Al composites was studied furtherly.1)The Fe2O3 mass ratio was varied in the range from 70 to 72%,the power loss of Mn Zn ferrite was decreased firstly,then raised.And the change of initial permeability(?i)was inversely with power loss.When the mass of Fe2O3 and Zn O was 71.5 wt% and 23.5 wt%,respectively,the ferrite material possessed the lowest power loss in the temperature range from 25 to 120?.And,the saturation magnetism was changed smoothly and uniformly from low to high temperature.Additionally,the ferrite material had good low power loss characteristics,which was loss from 275 to 360 k W/m3.Therefore,the best mass ratio of Mn Zn ferrite component of Fe2O3: Mn O: Zn O was 71.5: 23.5: 5.0(wt%).2)With the increasing of secondary ball milling time,the particle size distribution of powders was decreased.Meanwhile,the solid phase reaction rate was accelerated.By controlling the particle size distribution via the secondary milling,the proper solid action rate was obtained.While the ball milling time was 1.5 h,the particle size was less than 0.5 ?m,the proportion was 50%,and the proportion of 1 to 2 ?m was 90%.The sintered body with uniform grain growth,low porosity,had the maximal density and initial permeability.Hence,when the ball milling time was 1.5 h and the temperature range is 25 to 120 ?,the powders' particle size activity was the best,and the lowest total loss of Mn Zn ferrite was less than 310 k W/m3(Bm is 200 m T,f is 100 k Hz).3)The powders' surface was modified and the activation energy was augmented by mechanochemical method.In additional,a spinel-structured Mn Zn ferrite was synthesized by the solid phase reaction after sintering at 1200 ? for 5 h.Mn Zn ferrite powders were mixed into flaky Fe Si Al powders according to the different ratios of 0,5 wt%,10 wt%,15 wt% respectively.The composite material with microwave absorption function of Mn Zn ferrite Fe Si Al was prepared when the mass ratio of ball to material was 20: 1,and the ball milling time was 3h,the rotating speed was 300 r/min.The distribution and morphology of Mn Zn ferrite and Fe Si Al in composite materials were analyzed.The electromagnetic parameters were measured,and the electromagnetic wave shielding efficiency and the reflection loss were calculated respectively.