Low-temperature sintering and densification kinetics of sol-gel derived lithium-mica glass-ceramics through MgF2 addition

Abstract The aim of the current research is to investigate the low-temperature sintering of a nano-crystalline lithium-mica glass-ceramic. Sol-gel technique was used to prepare the glass-ceramics by application of LiMg 3 AlSi 3(1+x) O 10+6x F 2 with various x values (0.25, 0.5, 0.75, and 1) and different amounts of MgF 2 as the sintering aid. Use of appropriate amounts of additive and stoichiometric deviation (x) decreased the sintering temperature to 750 °C. Results also revealed that the highest relative density was achieved by applying the optimal amount of additive (4 wt%) with x = 1. The densification activation energy for the glass-ceramic containing 4 wt% MgF 2 was calculated as 214.33 ± 17 kJ mol −1 ; it was lower than the sample containing 5 wt% additive; hence it was confirmed as optimal content. Consequently, considering densification and phase analysis, true optimum amounts of MgF 2 were determined as 4, 4, 3 and 1 wt% for the glass-ceramics synthesized with x = 1, 0.75, 0.5 and 0.25, respectively.