Effects of Bi2O3-WO3 additive on microstructure and magnetic properties of low-temperature-fired MgCuZn ferrites

The low-temperature-fired MgCuZn ferrites with various amounts of Bi2O3 and WO3 additives were prepared by a conventional solid-state reaction method. The effects of Bi2O3 and WO3 additives on sintering behavior, microstructures and magnetic properties of MgCuZn ferrites were investigated. It is found that Bi2O3 and WO3 additives overtly improve the densification of samples through the formation of liquid phase and grains growth. Appropriate Bi2O3 and WO3 additives not only can noticeably increase the initial permeability (mu (i) ) and saturation flux density (B (s) ), but also can obviously reduce coercive field strength (H (c) ). However, too much additive will deteriorate the magnetic properties. The ferrite sample with 0.1 wt% Bi2O3 and 0.1 wt% WO3 shows excellent magnetic properties: mu (i) = 703.27 at 100 kHz, B (s) = 213.28 mT, B (r) = 117.98 mT and H (c) = 44.01 A m(-1).