Influences of Calcination Temperature on Densification and Magnetic Properties of Bi-Modified NiCuZn Ferrites

The influences of calcination temperature on the densification, microstructures, and magnetic properties of low-temperature-fired Bi-modified NiCuZn ferrites have been investigated in order to adapt the development of low-temperature cofired ferrites technology and produce high-frequency devices with a multilayer process. It is found that with increasing calcination temperature, some Bi³⁺ ions enter into the spinel lattice gradually, and consequently improve the microstructural uniformity and densification. Thus, the quality factor increases observably while the real permeability decreases a little. Optimized magnetic properties and linear sintering shrinkage can be obtained for Bi-modified NiCuZn ferrites calcined at proper temperature due to uniform microstructures with small grain size, and higher sintering density.