CuO-based sintering aids for low temperature sintering of BaFe12O19 ceramics

This paper describes the effect of addition of 2 wt% of CuO, 30 mol% BaO–70 mol% CuO and BaCuO2 liquid phase sintering aids on the densification, microstructure and magnetic properties of BaFe12O19 ceramics. Addition of the sintering aids enabled reduction of the sintering temperature from 1250 °C to 1100 °C. The sintering aids caused abnormal grain growth in ceramics sintered at 1100 °C, with CuO having the strongest effect. All samples sintered at 1250 °C showed abnormal grain growth. Addition of CuO and BaO–CuO caused the grain size distribution to shift to larger values compared to the sample without sintering aid. The effect of the sintering aids on grain growth behavior is explained using the interface-reaction control theory of grain growth. The increase in grain size caused a reduction in coercivity of the samples with sintering aid addition, particularly in the samples sintered at 1100 °C.