High-temperature in situ analysis of crystallisation for functional oxide vitro-ceramics – HighFive

HighFive is a fundamental research project which aims to decipher glass crystallisation processes in functional oxide (glass-)ceramics by new state-of-the-art high-temperature in-situ techniques. Bulk oxide glasses will be synthesised by advanced containerless melt-quenching on a new second-generation aerodynamic levitation system installed at CEMHTI in 2022, which already demonstrates unprecedented control and cooling possibilities. The project will focus on four key materials types, all developed recently by the CERAM team, whose properties (including ionic conduction, luminescence and tunable thermal expansion) show a marked dependence on their crystallisation conditions. Their crystallisation mechanisms, ranging from heterogeneous crystallisation arising from nucleating agents/surface/phase separated glasses to homogeneous crystallisation, will be studied by a combination of in-situ techniques including state of the art transmission electron microscopy using nanoscale and possibly atomic scale imaging and spectroscopy mapping. This is made possible by recent technical advances in in-situ TEM methods linked to sample drift, defocusing and irradiation problems. Such advances will allow us to build upon our current expertise, including a first TEM in-situ study of TiO2 crystallisation in SiO2 matrix from ambient conditions up to 600°C, to enable a paradigm shift in glass crystallisation understanding and development of innovative structures and properties.