Surface and volume crystallization in fluorrichterite based glasses

Abstract

F-richterite based glasses in the SiO 2-CaO-MgO-Na 2 OF system were investigated by X-ray diffraction, differential scanning calorimetry and field emission scanning electron microscopy to ascertain the influence of fluorine content on preferential crystallization mechanism and on the spatial position of crystals developed in the initial steps of glass devitrification. The results highlight that both surface and volume mechanisms occur in the crystallization of fluorrichterite glasses. However, these glasses preferentially devitrify by a surface crystallization mechanism, although an increase of fluorine content leads to a modification in the location of the first developed crystals.

Crystallization Kinetics in a Glass-Forming Hybrid Metal Halide Perovskite

“…This study shows two clear trends: (a) increasing propensity toward crystallization (nucleation) for smaller feature size, with T p shifting to lower values and (b) increasing crystallization peak intensities (indicative of higher nucleation density) as the SNPB glass particle size is reduced from bulk monolith to flakes to finely powdered configuration (progressing to higher surface-to-volume ratio). These trends reveal the underlying surface-dominated nucleation mechanism ,− and are not unique to SNPB, but have been observed in other glass-forming systems. , Importantly, there are two features in the DSC profile of flakes and powdered glass samples. We hypothesize that the narrow feature corresponds to sudden nucleation (shifts to lower temperature with reduction in particle size from flakes to powder), whereas the broad feature corresponds to crystal growth.…”