Low-temperature sintering of M-type barium ferrite with BaCu(B2O5) additive

The aim of this work is to lower the sintered temperature of M-type barium ferrite (BaM) by BaCu(B2O5) (BCB) additives. The effects of BCB additives on the sintering behavior, structure and magnetic properties of BaM were also discussed. It was found that the sintered density, saturation magnetization and initial permeability of BaM are modified obviously as small amount of BCB (1-4 wt%) is added. Especially, when BaM with 3 wt% BCB was sintered at 900 deg. C, the single-phase BaM was obtained and showed excellent properties with sintered density of 4.88 g/cm3, saturation magnetization of 61.4 emu/g and initial permeability of 3.15. In addition, the SEM result revealed that the sample can be co-fired well with the Ag electrode at 900 deg. C. The reason for this was attributed to be the formation of the BCB liquid phase. It suggests that this M-type barium ferrite can be used as LTCC substrate for millimeter wave circulator, filter and other magnetic microwave devices. - Highlights: → The BaCu(B2O5) can lower the sintering temperature of barium ferrite. → Crystallization of BaFe12O19 was speeded up by the BaCu(B2O5) liquid phase. → Proper BaCu(B2O5) liquid phase make the saturation magnetization (Ms) increase, once its excess, leading to degradation in Ms.