The effects of a complex nucleating agent with different ratios of MgF2/LiF on the crystallization and performance of lithium aluminum silicate glasses

Abstract Glasses and glass-ceramics with compositions (in wt%) of F6-93{SiO2-Al2O3-Li2O-P2O5-Sb2O3-MgO}-4{TiO2-ZrO2}-2.5MgF2-0.5LiF and F7-93{SiO2-Al2O3-Li2O-P2O5-Sb2O3-MgO}-4{TiO2-ZrO2}-2MgF2-1LiF were prepared using the traditional melt quenching technology and two-step (nucleation-crystallization) method. The effects of different proportions of MgF2 and LiF contents on the crystallization mechanism and performances of the glasses and glass-ceramics were examined using X-ray diffraction, differential scanning calorimetry, Fourier transform infrared and scanning election microscopy analyses. The result reveals that the Sample F6 with a higher proportion of MgF2 has worse performance in the parent glass but better crystallization performance in the glass-ceramic than F7 because of its faster increase of the frequency factor in the nucleating and crystallization processes (although it has a smaller boost effect of reducing crystallization energy than F7). Simultaneously, a high proportion of MgF2 is beneficial to accelerate the transition speed of β-quartz to β-spodumene and to more quickly stimulate the precipitation of the ZrTiO4 phase.