Effects of Li2CO3 addition on the microstructure and magnetic properties of low-temperature-fired NiCuZn ferrites

NiCuZn ferrites doped with 0.5 wt% Bi2O3 and different Li2CO3 contents (0-0.25 wt%) were sintered at 900 °C. The microstructure and magnetic properties of these materials were investigated. The addition of low-melting-point Li2CO3 led to large and uniform grains. However, excess Li2CO3 addition produced abnormal grains and many closed pores, thereby reducing density. Permeability initially increased and then decreased at the Li2CO3 content of >0.2 wt%. Maximum magnetic flux density (431.1 mT at room temperature, 339.6 mT at 100 °C) and minimum power loss were achieved at 0.2 wt% Li2CO3. These findings suggested the suitability of 0.2 wt% Li2CO3 for applications in low-temperature co-fired ceramic magnetic power components and modules.