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 glassceramicsrnwith various contents of P2O5 in the basic Li_2O-SiO_2 glass system. The glass wasrnmelted at 1480 ℃ for 1h. The object of observation was the preparing crystal phase ofrnfluoroapatite in amorphous glass matrix. The morphology of lithium disilicate glass-ceramicsrnwas studied by SEM. The crystal growth and thermal properties of fluoroapatite was studied byrnX-ray diffraction and DTA. The more the content of P_2O_5, the more the presence of fluoroapatiternparticles. SEM investigation clearly indicated the phase separation and formation of primaryrncrystallic phase of fluoroapatite in the studied glass-ceramics. DTA curves of the fluoroapatiternsamples exhibit the exothermic effects in the temperature range 337-694℃ depending on therncomposition of the materials. The position of exothermic peak for lithium disilicate on DTArncurves moves with increasing specific surface towards lower temperatures which points on itsrnpreferential surface crystallization. As far as physical qualities are concerned, mainly color andrngloss, the best qualities of all observed materials belong to glass-ceramics with 10% P_2O_5.