Effect of Crystal Size on the Surface Roughness in Li2O-Al2O3-SiO2 (LAS) Glass-Ceramics System

초록

The peculiar ultralow thermal expansion properties are most significant in some widespread applications such as telescope mirror bank, ring-laser gyroscopes, optically stable platforms, and cooktop panels. For these materials, LAS (Li2O-Al2O3-SiO2) glass-ceramics system has been used because of low thermal expansion (ranging from -86 x 10-7?-1) with the formation of β-quartz. In this study, the LAS glass-ceramics system was evaluated with the surface roughness and transmittance based on the crystal size using SEM, AFM (Atomic Force Microscopy) and UV- visible spectrometer. With increasing heat treatment temperature, the number of crystals per unit area decreased and the surface roughness increased, which were dependent on the crystal size and crystal types in LAS glass-ceramics system. Also, transmittance of glass-ceramics decreasedwith increasing crystal size.Based on the results, it suggests that the crystal phase and size in the glass-ceramic play an important role for surface roughness and transmittance of glass-ceramics.