Effect of SiO_2 Content on the Electromagnetic Properties of CoZn-Z Type Barium Ferrite Prepared with Ferrous Micro-beads

摘要

Ferrous micro-beads from fly-ash were used as starting material to prepare CoZn-Z type barium ferrite. As the main impurity in the beads, SiO_2 plays an important role on the electromagnetic properties of the ferrites. To investigate the effect of SiO_2 content, a series of CoZn-Z type ferrites with various contents of SiO_2 (1 wt%, 2 wt% and 5 wt %) were prepared with analytical pure Fe_2O_3 and SiO_2. The density, phase composition, microstructure and electromagnetic properties of the sintered samples were investigated. The results show that the permeability of samples alters little at a low content of SiO_2 about 1 wt%, but deteriorates dramatically when the addition of SiO_2 is above 2 wt%. The ferrous micro-beads were then treated by alkali cleaning to reduce the content of SiO_2 to about 1 wt%, and the samples prepared with these treated beads show a similar performance on the electromagnetic properties with pure CoZn-Z type ferrite.