Transparent single crystalline ZrO2-SiO2 glass nanoceramic sintered by SPS

Transparent ZrO2-SiO2 glass ceramics show potential for application in the dental industry. The application of this material prepared by a sol-gel method was hindered by the difficulties in obtaining large dimension samples. Spark plasma sintering (SPS) offers the possibility of achieving transparent ZrO2-SiO2 glass ceramics. In this study, a ZrO2-SiO2 powder was prepared by the sol-gel method and subsequently sintered by SPS. Varied sintering temperatures and pressures were explored to achieve better mechanical strength and transparency. TEM results showed single crystalline ZrO2 spherical nanocrystals (approximately 20nm) homogenously embedded in the SiO2 matrix. Tetragonal ZrO2 was the only crystalline phase in all specimens. With sintering conditions of 1200°C and 30MPa, a glass ceramic with fracture toughness of 4.13MPa m was obtained. This value is similar to the commercial dental glass ceramic of IPS e.max® Press. The studied transparent glass ceramic with high transparency and moderate mechanical strength shows promise for dental application.