The Effect of Nb2O5 Addition on the Microstructure and Magnetic Properties of MnZn Ferrites

摘要

MnZn ferrites with the chemical formula Mn0.68Zn0.25Fe2.07o4 have been prepared by conventional ceramic techniques. Toroidal cores were sintered at 1350°C for 4h in N2/O2 atmosphere with 4% oxygen. Then the influence of Nb2O5 addition on the microstructure and magnetic properties of MnZn ferrites was investigated by characterizing the fracture surface micrograph and measuring the magnetic properties. The results show that, the initial permeability and saturation magnetic flux density increase and power losses decrease when the Nb2O5 concentration is not more than 0.04wt%. The average grain size increases with the increase of Nb2O5 concentration. However, excessive Nb2O5 concentration (>0.04wt%) results in the exaggerated grain growth and porosity increase which result in the initial permeability and saturation magnetic flux density decrease and power losses increase.