Low-temperature-fired NiCuZn ferrites with BBSZ glass

Abstract

Addition of BBSZ (27% Bi 2O 3, 35% H 3BO 3, 6% SiO 2, and 32% ZnO in mol%) glass has been used to enhance densification and improve the magnetic properties of low-temperature-fired NiCuZn ferrites. It was found that the BBSZ glass did not form a visible second phase in our testing range. However, the densification and microstructure of the ferrites were initially very sensitive to the BBSZ glass content. Even a slight increase in BBSZ glass content from 0.25 to 0.5 wt% was sufficient to change the ferrite samples from not being well sintered with a uniform microstructure and very small grain size to a typical bimodal, inhomogeneous microstructure. It proved to be better to add more BBSZ glass than the critical content to obtain the appropriate microstructure and magnetic properties. In this study, a ferrite sample with 0.75 wt% BBSZ glass gave the best performance in terms of densification, microstructure, permeability, and Q-factor characteristics.