CeO2 and Y2O3 as nucleation inhibitors in lithium disilicate glasses
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Stoichiometric lithium disilicate glasses were doped with up to 3 mol% CeO2 or Y2O3 and the nucleation and crystal growth kinetics were determined as a function of temperature using in situ hot-stage microscopy. The additives led to a decrease of the steady-state nucleation rates by up to two orders of magnitude and a remarkable increase of the induction time. Moreover, the crystal growth velocities are notably decreased, while the activation energy for crystal growth increases. The cerium-containing samples were analyzed by fluorescence microscopy and spectroscopy, scanning electron microscopy as well as cathodoluminescence measurements. The lithium disilicate crystals consist of fine lamellae separated from each other by a cerium-enriched residual glassy matrix and the crystallization front is enriched by the added oxide. As a result, CeO2 and Y2O3 act as nucleation inhibitors in lithium disilicate glass.
KeywordsCerium CeO2 Y2O3 Nucleation Rate Crystallization Front
The authors thank Sven Schönherr from the Institute for Solid State Physics, Jena University, for the cathodoluminescence and EDX measurements.
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