초록 ▼

There are disclosed glass-ceramic materials characterized by a nepheline crystal phase and optionally having a secondary celsian or hexacelsian crystal phase. In addition to the SiO2, Al2O3, Na2O, and TiO2 as a nucleating agent, the materials contain K2O and/or Li2O in limited amount, and preferably

There are disclosed glass-ceramic materials characterized by a nepheline crystal phase and optionally having a secondary celsian or hexacelsian crystal phase. In addition to the SiO2, Al2O3, Na2O, and TiO2 as a nucleating agent, the materials contain K2O and/or Li2O in limited amount, and preferably also contain BaO. These additives provide microwave compatibility, a thermal coefficient of expansion below 95×10-7/°C., and suitability for application as glazed table or ovenware.

대표청구항 ▼

A glass-ceramic body in which the primary crystal phase is composed of nepheline crystals less than 20 microns in diameter, the body has a microwave compatibility value of less than 150°C., and the composition of the body, in percent by weight as calculated on an oxide basis, consists essentially of

A glass-ceramic body in which the primary crystal phase is composed of nepheline crystals less than 20 microns in diameter, the body has a microwave compatibility value of less than 150°C., and the composition of the body, in percent by weight as calculated on an oxide basis, consists essentially of 30-55% SiO2, 28-38% Al2O3, 5-12% TiO2 as a nucleating agent, and 10-20% R2O (Na2O+K2O+Li2O), each mole of R2O being composed of 0.65-0.95 moles Na2O, 0.05-0.15 moles Li2O and 0-0.20 moles K2O.