The Growth Of Fluoroapatite Bio-Glass-Ceramics, Precipitated In Lithium Disilicate Glasses: Thermoanalytical And Morphological Study

摘要

This work is focused on the observation of changes in structure of fluoroapatite glassceramics with various contents of P2O5 in the basic Li_2O-SiO_2 glass system. The glass was melted at 1480 °C for 1h. The object of observation was the preparing crystal phase of fluoroapatite in amorphous glass matrix. The morphology of lithium disilicate glass-ceramics was studied by SEM. The crystal growth and thermal properties of fluoroapatite was studied by X-ray diffraction and DTA. The more the content of P_2O_5, the more the presence of fluoroapatite particles. SEM investigation clearly indicated the phase separation and formation of primary crystallic phase of fluoroapatite in the studied glass-ceramics. DTA curves of the fluoroapatite samples exhibit the exothermic effects in the temperature range 337-694°C depending on the composition of the materials. The position of exothermic peak for lithium disilicate on DTA curves moves with increasing specific surface towards lower temperatures which points on its preferential surface crystallization. As far as physical qualities are concerned, mainly color and gloss, the best qualities of all observed materials belong to glass-ceramics with 10% P_2O_5.