Abstract
An oxyfluoride glass with the composition of 25CaF2-5CaO-20Al2O3-50SiO2 (mol%) and optically transparent crystallized glasses containing CaF2 nanocrystals (10-60 nm) were fabricated, and their mechanical behaviors were estimated using Vickers tests and nanoindentation techniques (quasi-static and continuous stiffness measurements). The Vickers hardness (HV) increased due to the formation of CaF2 nanocrystals, i.e., HV=5.5 GPa for the glass and HV=6.0 GPa for the sample heat-treated at 720˚C. The indentation hardness (Hin) at the surface of 200-500 nm showed Hin=7.8-8.3 GPa for the glass and Hin=8.4-8.8 GPa for the sample heat-treated at 700˚C. The deformation mechanism at the surface of oxyfluoride crystallized glasses has been discussed.
