High toughness transparent glass‐ceramics with petalite and β‐spodumene solid solution as two major crystal phases

Abstract

AbstractLithium aluminosilicate glass‐ceramics are well known for good transparency, high fracture toughness, low thermal expansion, and good ion exchange ability. In this study, new transparent Li2O‐Al2O3‐SiO2 (LAS) glass‐ceramics with petalite and β‐spodumene solid solution as the major crystalline phases were invented for favorable mechanical properties and potential for application in the hollowware, tableware, container, and plate glass industries. Crystal phases are mainly influenced by the ratio of Al2O3 to SiO2 concentrations. The concentration of SiO2 required to form specific crystalline phases in the glass‐ceramics is higher than that inferred from the ternary phase diagram. Al2O3 content is required to be sufficiently high for the formation of crystals, instead of balancing excess amounts of Li2O in the glass. The average transmittances of 2.0 ± 0.1 mm thickness samples in visible light regions (400–700 nm) can reach more than 80% with crystal sizes of 20–40 nm. Transmittance is significantly decreased for heat treatments around 710°C, due to the high growth rate of β‐spodumene solid solution crystals. Vickers hardness, indentation toughness, and crack probabilities of transparent LAS glass‐ceramics are significantly improved compared with standard soda lime silicate glass, due to the crack bridging and deflection of crystal grains.