New Sintered Li2OAl2O3SiO2 Ultra-Low Expansion Glass-Ceramic

We developed a new Li2OAl2O3SiO2 (LAS) ultra-low expansion glass-ceramic by nonisothermal sintering with concurrent crystallization. The optimum sintering conditions were 30 degrees C/min with a maximum temperature of 1000 degrees C. The best sintered material reached 98% of the theoretical density of the parent glass and has an extremely low linear thermal expansion coefficient (0.02x106/degrees C) in the temperature range of 40 degrees C500 degrees C, which is even lower than that of the commercial glass-ceramic Ceran (R) that is produced by the traditional ceramization method. The sintered glass-ceramic presents a four-point bending strength of 92 +/- 15MPa, which is similar to that of Ceran (R) (98 +/- 6MPa), in spite of the 2% porosity. It is white opaque and does not have significant infrared transmission. The maximum use temperature is 600 degrees C. It could thus be used on modern inductively heated cooktops.