High Q-factor NiCuZn ferrite with nanocrystalline ferrite particles and Co_2O_3 additives

摘要

This work focuses on the effects of nanocrystalline ferrite particles (NFPs) on the sintering behaviour and magnetic properties of NiCuZn ferrite for multilayer chip inductor use. It was found that the NFPs could evidently improve the sintering behaviour of the ferrite because of their large surface free energy. Because the NFPs had the same chemical composition as the NiCuZn ferrite, samples with appropriate NFPs added could show better magnetic properties than samples with added Bi_2O_3. Also, to further increase the Q-factor of the NiCuZn ferrite, the effects of Co_2O_3 additive on the magnetic properties of the NFP-added ferrite were studied. The results revealed that the permeability of the ferrite decreased monotonically due to added Co_2O_3; the Q-factor first increased and reached its peak with 0.2 wt% Co_2O_3 added, whereupon it began to decrease. With 30 wt% NFPs and 0.2 wt% Co_2O_3 additives, the NiCuZn ferrite showed a high Q-factor of more than 200.