2024
ACL
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Arthur Cachot, Leire del Campo, Lionel Cosson, Sandra Ory, Emmanuel Veron, Mohammed Malki, 'Highlighting amorphous phase separation process on cooling borosilicate melts using impedance spectroscopy', J. Non-Cryst. Solids 641 (2024) doi:10.1016/j.jnoncrysol.2024.123155
Four samples of sodium borosilicate glasses of composition (100 - x)(SiO2 - B2O3) - xNa2O with x = 4, 7, 10 and 25 mol% were synthesized and studied in a wide temperature range (up to 1673 K) using impedance spectroscopy, from the molten to the solid states. During melt cooling of three compositions (x = 4, 7 and 10), a clear transition was observed on the conductivity behavior at a critical temperature (Tcrit ≈ 973 K), highlighting the onset of an amorphous phase separation, in agreement with both Differential Scanning Calorimetry thermograms and literature. The amorphous nature of the phase separated samples was verified by in situ X-Ray Diffraction measurements performed under the same thermal conditions. Furthermore, Scanning Electron Microscopy micrographs taken on these three samples at room temperature after the impedance measurement confirmed the presence of two different phases, whose size and morphology vary with composition. As expected, the x = 25 sample did not show phase separation and remained homogeneous down to room temperature.
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