| Abstract Scope |
Titanate brannerites (ATi2O6, A = Ce4+, U4+, Th4+) are candidate wasteform materials for the immobilisation of high actinide content nuclear wastes, either alone, as ceramic phases in glass-ceramic composites, or as one phase in a complex multiphase ceramic. The Ce-endmember (prototypically CeTi2O6) has complex behaviour not seen in the U and Th analogues, including temperature dependent autoreduction balanced by formation of O vacancies, and an anomalously low melting temperature (approximately 1365 °C).
In this work the melting behaviour of Ce-brannerite and a mechanical mixture of CeO2 + 2TiO2 has been examined using in-situ characterisation methods at high temperature, including: Raman spectroscopy, millimetre wave spectroscopy, and thermal analysis techniques. The cause of the anomalously low melting temperature of this material has been investigated, and its relation to the temperature dependent Ce3+/Ce4+ redox couple examined. |