Stabilisation of MnZn ferrites by the re-oxidation of their grain boundaries

MnZn ferrites, sintered at various oxygen partial pressures, were subjected to a post-sintering thermal treatment below the sintering temperature wher e no additional grain growth can be expected. The ferrites were stabilised at '100 degreesC and different oxygen partial pressures for various times w ere applied in order to improve the intrinsic and extrinsic properties. The most promising results were obtained after the ferrites were stabilised at 1100 degreesC and 0.7 vol.% of oxygen. During the stabilisation, the level of Fe2+ ions in the bulk ferrite were substantially changed as were the in trinsic properties. In addition, an increase in the segregation of aliovale nt ions at the grain boundaries was noted, which leads to a change in the e xtrinsic properties. All these changes have a strong effect on the final pe rformances of the MnZn ferrites.