Enhanced grain-boundary diffusion on power loss of low-temperature-fired NiCuZn ferrites for high-frequency power supplies

Abstract

NiCuZn ferrite ceramics with high permeability, low power loss and excellent thermal stability are vital materials for high-frequency power devices. This paper analyzed grains growth and grain-boundary diffusion of Ni0.2Cu0.2Zn0.6Fe2O4 ferrite ceramics at lower temperatures by adding optimized additives. X-ray diffraction reveals that the samples are pure spinel ferrite phase sintered at low temperatures. SEM images indicate that uniform and compact NiCuZn ferrite ceramics were obtained at 920 °C for 4 h, which is very advantageous for low-temperature co-fired ceramic (LTCC) technology. In addition, the ferrite ceramics with higher permeability (~ 411 @ 1 MHz), lower power loss in high frequency (~ 442 kW/m3 @ 7 MHz) and good thermal stability were synthesized by controlling grains growth and grain-boundary diffusion. The results indicate that this ferrite ceramic material is a good candidate for the application of miniaturized power electronics in high frequency.