Structural and Textural Modifications of Ternary Phosphate Glasses by Thermal Treatment

摘要

Phosphate-based glasses of composition xNa2O-(45+(10-x))CaO-45P2O5 with different Na2O, CaO (x =1, 5, 10, 15, and 20 mol%), and invariable P2O5 (45 mol%) contents were prepared using the rapid melt quench technique. The obtained thermal data from differential thermal analysis revealed a decline in glass transition (Tg) and crystallization (Tc) temperatures of glasses against the compositional changes. The inclusion of Na2O at the cost of CaO in the glass network led to a reduction in its thermal stability. The thermal treatment carried out on glasses helped to derive their glass-ceramic counterparts. The amorphous and crystalline features of samples were characterized using X-ray diffraction patterns. The crystalline species that emerged out of the calcium phosphate phases confirmed the dominance of Q1 and Q2 structural distributions in the investigated glass-ceramics. The obtained scanning electron micrographs and atomic force microscopic images confirmed the surface crystallization and textural modification of the samples after thermal treatment. The N2-adsorption—desorption studies explored the reduction of porous structures due to thermal treatment on the melt-driven glass surface. The measured elastic moduli and Vicker's hardness values of the glasses showed an increase after thermal treatment, which were reduced against the inclusion of alkali content in both glass and glass-ceramics.