Sintering, microstructure and magnetic properties of low-temperature-fired NiCuZn ferrites doped with B2O3

Sintering behavior, microstructure and electromagnetic properties of NiCuZn ferrites doped with B2O3 sintered in the temperature range of 850-950 °C were investigated. It is found that a small amount of B2O3 (=0.05 wt%) not only improves the sinterability, but also can noticeably increase the initial permeability (μi), saturation flux density (Bs), remanent flux density (Br) and reduce the coercive field strength (Hc). At B2O3 contents >0.05 wt%, more porosity and liquid phase appear leading to deteriorate magnetic properties. The ferrite sample with 0.05 wt% B2O3 sintered at 925 °C shows optimal microstructure and excellent synthetical magnetic properties: μi=826.41 at 1 MHz, Bs=341.8 mT, Br=165.5 mT and Hc=29.09 A m−1.