COMPOSITIONS OF SILICON-SODIUM-CALCIUM GLASSES Russian patent published in 2006 - IPC C03C3/87 

FIELD: glass industry.

SUBSTANCE: invention proposes the glass composition for making a substrate of thermal stable plate that comprises components taken in the following ratio, %: SiO₂, 45-63; Al₂O₃, 0-18; ZrO₂, 6.5-20; Na₂O, 2-12; K₂O, 3.5-9; CaO, 1-13; MgO, 0-8. The total content of oxides SiO₂, Al₂O₃ and ZrO₂ is 70% or less; the total content of alkaline metal oxides NaO and K₂O is 8% or above. The proposed composition comprises if necessary oxides BaO and/or SrO in the following ratios: 11% ≤ MgO + CaO + BaO + SrO ≤ 24%. Glass shows the reduced hardening temperature (deformation temperature) equal to 530°C or above, and coefficient of expansion (α_25-300°C) (80-95) x 10^-7/°C. This glass composition can be used in preparing a substrate for emission screen and for making fireproof glazing. Invention provides preparing a plate with practically zero deformation at temperature 550-600°C.

EFFECT: improved and valuable properties of glass composition.

12 cl, 2 tbl