Microstructure and magnetic properties of low-temperature-fired NiCuZn ferrites with various borosilicate glasses

The low-temperature-fired NiCuZn ferrites with various borosilicate glasses were prepared by the conventional solid-state reaction method. Different weight percentages of glasses such as Al₂O₃–B₂O₃–SiO₂ (ABS), Na₂O–Al₂O₃–B₂O₃–SiO₂ (NABS), Bi₂O₃–B₂O₃–BaO–SiO₂ (BBBS) were added to low-temperature-fired NiCuZn ferrites. The effects of these glasses on sintering behavior, microstructures and magnetic properties of NiCuZn ferrites were also investigated. It is found that moderate amount of borosilicate glass addition can promote the densification and improve the magnetic properties of NiCuZn ferrites due to the formation of liquid phase, but too more liquid phase formation will deteriorate the magnetic properties. In addition, results also show that addition of BBBS glass can promote best densification of NiCuZn ferrites, but improve magnetic properties worse than addition of ABS or NABS glass. By contrast, the NiCuZn ferrite sample with 0.1 wt% ABS glass can obtain best magnetic properties: μ _i  = 733.01 at 100 kHz, B _s  = 162.39 mT, B _r  = 86.59 mT and H _c  = 35.7 A m⁻¹.