New Sintered Li ₂ O – Al ₂ O ₃ – SiO ₂ Ultra‐Low Expansion Glass‐Ceramic

Abstract

We developed a new Li 2 O – Al 2 O 3 – SiO 2 ( LAS ) ultra‐low expansion glass‐ceramic by nonisothermal sintering with concurrent crystallization. The optimum sintering conditions were 30°C/min with a maximum temperature of 1000°C. The best sintered material reached 98% of the theoretical density of the parent glass and has an extremely low linear thermal expansion coefficient (0.02 × 10 −6 /°C) in the temperature range of 40°C–500°C, which is even lower than that of the commercial glass‐ceramic Ceran ® that is produced by the traditional ceramization method. The sintered glass‐ceramic presents a four‐point bending strength of 92 ± 15 MPa, which is similar to that of Ceran ® (98 ± 6 MPa), in spite of the 2% porosity. It is white opaque and does not have significant infrared transmission. The maximum use temperature is 600°C. It could thus be used on modern inductively heated cooktops.