Effects of composition and sintering temperature on properties of NiZn and NiCuZn ferrites

Effects of composition and sintering temperature on grain size, porosity and magnetic properties of the NiZn and NiCuZn ferrites were investigated. It was found that the lowest power loss could be obtained with the equimolar composition for both NiZn and NiCuZn ferrites, which could be attributed to the lowest porosity. A slight deficiency or excess of Fe2O3 content had no pronounced influence on saturation magnetic flux density (Bs) in our testing range. However, a slight excess of Fe2O3 was effective to improve the initial permeability, which could be attributed to decrease of the magnetocrystalline anisotropy. With the increase of sintering temperature, the initial permeability and power loss of the NiZn and NiCuZn ferrites had different development trend, which could be explained by the different variation trend of the grain size and porosity. Power losses of the NiCuZn ferrite samples were lower than that of the NiZn ferrite samples at any sintering temperature. Synthetically, the NiCuZn ferrites had a better performance than the NiZn ferrites in power field use.