Influence of B2O3–MoO3 addition on microstructure and magnetic properties of low-temperature-fired NiCuZn ferrites

The low-temperature-fired NiCuZn ferrites with different amounts of B2O3 and MoO3 additions were prepared by a conventional solid-state reaction method. The sintering behavior, microstructure and magnetic properties of the ferrites sintered at 925 °C were investigated. It is found that B2O3 and MoO3 additions obviously improve the densification of specimens due to the liquid phase formation and grain growth promotion. The appropriate B2O3 and MoO3 mixed additions not only can noticeably increase the initial permeability (μi) and saturation flux density (Bs), but also can obviously reduce the remanent flux density (Br) and coercive filed strength (Hc). However, the more liquid phase formation and abnormal grain growth will deteriorate the magnetic properties. The ferrite sample with 0.05 wt% B2O3 and 0.5 wt% MoO3 shows excellent magnetic properties: μi=985.29 at 100 kHz, Bs=279.54 mT, Br=102.93 mT and Hc=33.88 A m−1.