Effect of Bi2O3 and Co2O3 co-doping on power loss characteristics of low-temperature-fired NiCuZn ferrites

Abstract

Low-temperature-fired NiCuZn ferrites with fixed 0.25 wt% Bi2O3 doping and different Co2O3 doping contents (0–0.5 wt%) were prepared using solid-phase reaction method. In addition, phase composition, microstructure, and magnetic properties of the ferrites, especially their power loss characteristics, were investigated. Results show that the permeability decreased while the coercivity increased with increase in Co2O3 content. Sintered density and saturation flux density (Bs) first increased and then decreased. The maximum density and Bs values were obtained at Co2O3 doping contents of 0.35 and 0.25 wt%, respectively. The best power loss performance was obtained for the sample containing 0.3 wt% Co2O3 at different temperatures (25 °C and 100 °C) and different induction conditions (1–10 MHz and 5-20mT). The corresponding influence mechanisms were analyzed in detail. It was concluded that the NiCuZn ferrite doped with 0.25 wt% Bi2O3 and 0.3 wt% Co2O3 is the best choice for high-frequency and low-temperature co-fired ceramic applications as magnetic power components.