Effects of Bi2O3 addition on the microstructure and electromagnetic properties of NiCuZn ferrites

Effects of Bi2O3 addition on the microstructural development and magnetic properties of NiCuZn ferrites were studied. For low temperature sintering (< 900 degrees C), 0.1-1.0 wt % of Bi2O3 was added to the NiCuZn ferrites. The grain size and bulk density gradually increased with the increase in the Bi2O3 content. Above 0.5 wt% Bi2O3, abnormal grain growth was observed. The specimen with 0.25 wt% Bi2O3 showed the highest initial permeability with good quality factors and a uniform microstructure. However, the specimen with greater than 0.5 wt% Bi2O3 demonstrated abnormal grain growth with lower initial permeabilities and poor quality factors. (C) 2004 Kluwer Academic Publishers.