Kinetic study on the effect of adding P2O5 to the LMAS glass-ceramic

Glasses in the LMAS (Li2O, MgO, Al2O3, SiO2) system containing F, CaO, ZrO2, and TiO2 were subjected to crystallization by incorporating P2O5. The glass stability, glass forming ability, and crystallization kinetics have been determined. Crystals of Lithium Aluminum Silicate (LixAlxSi1-xO2), Enstatite (MgSi2O6) and B-spodumene (LiAlSi2O6) were detected in the samples containing F, but B-spodumene was not observed in the glass-ceramic in its absence. Glasses containing F show a dependence of the activation with the addition of P2O5 with energy values ranging from 426 kJ mol(-1) to 483 kJ mol(-1), being this maximum found for P2O5 amounts up to 3 mol%. High concentrations of P2O5 and Al2O3 improve the glass stability and increase the crystallization temperature. The most common crystallization mechanism is of bulk type with a constant number of nuclei. Two- and three-dimensional growth of crystals was observed in glasses containing F but in its absence and at high Al2O3 concentration bulk crystallization with twoand one-dimensional growth is observed. (C) 2019 SECV. Published by Elsevier Espana, S.L.U.