SrFe12O19 as an impurity in perovskite-type ferrites

A decrease of oxygen content in SrFe12O19 and its subsequent decomposition were studied at 750-950 degrees C by coulometric titration. The lowest oxygen content that strontium hexaferrite endures is about 18.5. Further oxygen removal from oxide lead to its reductive decomposition with the formation of Fe3O4 and Sr4Fe6O13+delta. The stability limits of SrFe12O19 under reducing conditions was determined. The continuation of the reductive titration was shown to result in the transformation Fe3O4 -> Fe1-xO followed by Fe1-xO -> Fe. The significant release of oxygen during stepwise decomposition can be considered as a specific characteristic of SrFe12O19. It is argued that the double stepwise fall, which is often observed on oxygen content isotherms of perovskite-type ferrites, indicates the presence of SrFe12O19 impurity. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The study investigated the decrease of oxygen content and subsequent decomposition of SrFe12O19 at 750-950 degrees C through coulometric titration. It was found that the stability limits of SrFe12O19 under reducing conditions were determined, and the stepwise decomposition process showed specific characteristics of SrFe12O19. The double stepwise fall observed on oxygen content isotherms may indicate the presence of SrFe12O19 impurity.