Nucleating role of P 2 O 5 in nepheline‐based transparent glass‐ceramics

Abstract 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 Na 2 O–Al 2 O 3 –SiO 2 ternary system nucleated with P 2 O 5 . 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 P 2 O 5 in the glass structure leads to the phase separation resulting in the crystallization of nanocrystalline Na 3 PO 4 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%).