| 摘要 |
Disclosed is heat stable glass composition containing 45 to 68 percent by weight of SiOi2, 0 to 20 percent by weight of Ali2Oi3, 0 to 20 percent by weight of ZrOi2, 0 to 10 percent by weight of Bi2Oi3, 2 to 12 percent by weight of Nai2O, 3.5 to 9 percent by weight of Ki2O, 1 to 13 percent by weight of CaO, 0 to 8 percent by weight of MgO, whereby the sum of the SiOi2, Ali2Oi3 and ZrOi2 oxide weight percentages is equal to or less than 70 percent by weight, the sum of the Ali2Oi3 and ZrOi2 oxide weight percentages is equal or greater than 2 percent by weight, the sum of the alkali metal Nai2O and Ki2O oxide weight percentages is equal or greater than 8 percent by weight and it can further contain BaO and/or SrO oxides in such amounts that 11 percent by weight the sum of the MgO + CaO + BaO + SrO oxide weight percentages is greater than or equal to 11 percent by weight but less than or equal to 30 percent by weight. This glass composition can be used for preparing substrates for emission grids or for refractory glass sheets. |
