Nucleating role of P2O5 in nepheline-based transparent glass-ceramics

The nepheline-based transparent glass-ceramics are promising candidates for cover glass applications in electronic displays owing to their superior mechanical properties (than glasses) and ability to be chemically strengthened. However, our poor understanding about the kinetic and thermodynamic drivers controlling their crystallization processes usually results in their opacification and development of large internal stresses. The present work focuses on the development of nepheline-based nanocrystalline transparent glass-ceramic designed in the Na2O-Al2O3-SiO2 ternary system nucleated with P2O5. The temporal evolution of the phosphate and nepheline nanocrystal formation has been followed using X-ray diffraction, scanning/transmission electron microscopy, and energy-dispersive spectroscopy. The incorporation of P2O5 in the glass structure leads to the phase separation resulting in the crystallization of nanocrystalline Na3PO4 as an intermediate phase; thus, acting as a nucleating site for volume crystallization of nepheline. The optimization of nucleation and growth profile in the designed composition results in the formation of a transparent glass-ceramic with high optical transmittance (91.5 +/- 0.1%).

Automated summary

This study focuses on the development of nepheline-based nanocrystalline transparent glass-ceramic designed in the Na2O-Al2O3-SiO2 ternary system nucleated with P2O5. By tracking the formation process of phosphate and nepheline nanocrystals, the optimization of nucleation and growth profile in the designed composition results in the formation of a transparent glass-ceramic with high optical transmittance.