Effect of ZrO2 crystallization on ion exchange properties in aluminosilicate glass

Abstract

Ion exchange has the potential to improve the mechanical properties of glass ceramics. In this work, ZrO2 nanocrystals embedded transparent glass ceramics were prepared and effect of the crystallization on ion-exchange properties was investigated. The crystallization of ZrO2 did not affect the transmittance and Vickers hardness due to the small nanocrystal size and the low crystallinity, but significantly enhanced the ion exchange depth of layer (DOL). X-ray diffraction, high resolution transmission electron microscope, Raman spectra and nuclear magnetic resonance analysis demonstrated that with the crystallization of ZrO2, the charge compensator (Na+) was released, which promoted the transformation of highly coordinated Al into [AlO4]− tetrahedral units and the formation of Na+ balanced non-bridging oxygens. These changes in structure of glass made the Na+ more mobile and increased the DOL upon the crystallization. Results reported here may be useful for the development of glass-ceramic materials suitable for chemical strengthening.