Preparation, Structure And Properties Of MgCuZn Ferrite

With the development of the miniaturization and lightness of electronic devices,and with the rapid development of telecommunication and computer technology, as akind of important electronic component, multilayer chip inductors have been deeplyresearched and got extensive applications. Up to now, the materials used for highfrequency multilayer chip inductors are mainly the NiCuZn ferrites. But recently,some researchers have found that MgCuZn ferrites have better magnetic and sinteringproperties than that of NiCuZn ferrites, and beause of the lower cost, MgCuZn ferritesare suitable for multilayer chip inductors.In this dissertation, we used analytical grade magnesium nitrate[Mg（NO₃）₂·6H₂O], zinc nitrate [Zn（NO₃）₂·6H₂O], copper nitrate [Cu（NO₃）₂·3H₂O]and iron nitrate [Fe（NO₃）₃·9H₂O] as the raw material, and prepared MgCuZn ferritesby adopting the chemical co-precipitation method. We mainly investigate the effect ofthe presintering temperature, sintering temperature and main ingredient on theproperties of MgCuZn ferrites by using the technology of X-ray diffractometer （XRD）,Vibrating sample magnetometer （VSM） and HP4194A impedance analyzer. Theinfluence mechanism were discussed carefully.With the presintering temperature in the rang of400℃～800℃, the bestmicrostructure and magnetic properties can be obtained at600℃, and bellow orexceeding this temperature, the microstructures and magnetic properties of sinteredMgCuZn ferrites become worse. The initial permeability, the density and thepermeability-temperature character of sintered ferrites increase with sinteringtemperature increasing.The effects of copper content on the microstructure and megnetic properties ofthe ferrite powders prepared by the co-precipitation method were investigatedsystematically. All the samples have been confirmed to form the cubic spinel structureof single-phase. With the increase in the Cu²⁺content, the saturation magnetizationand the initial permeability at first increase and then decrease. It was found that thecoercivity is in proportion to the crystallite size. The Curie temperature increase linelywith the copper content.Comparing with solid reaction method and sol-gel auto-combustion method, thefabricated MgCuZn ferrites by using the chemical co-precipitation method has the following advantages:（1） simple to operate and non-pollution,（2） the presinteringtemperature of obtaining the single-phase ferrite is low （just400℃）, and （3） thesintering temperature is also lower for getting the better magnetic properties.