Densification and properties of fluxed sintered NiCuZn ferrites

PbO . SiO2, PbO . B2O3 and Bi2O3 flux systems were used to lower the sinter ing temperature of an (Ni0.38Cu0.12Zn0.50)Fe2O4 ferrite. The PbO . SiO2 gla ss system was found to be the most effective additive to obstruct the grain boundary movement and prevent the exaggerated grain growth among these flu x systems. In addition, it significantly reduces the sintering temperature of the ferrite and results in ceramics with a small and uniform grain size. Ferrites sintered with PbO . SiO2 possess higher resistivity, higher Q and higher H-c compared with those of other systems. The results showed that t he addition of Bi2O3 considerably deteriorated the quality factor of NiCuZn ferrites, though benefited the densification and permeability. The results also revealed that the ratio of modifier to glass former (i.e. PbO:SiO2, o r PbO:B2O3 ratio) did not significantly change the densification behavior, microstructural evolution and magnetic properties of NiCuZn ferrite. (C) 20 00 Elsevier Science B.V. All rights reserved.