| 摘要 |
PURPOSE: A glass is provided which satisfies the above-mentioned requirements imposed on previous borosilicate glasses, has favorable working points and is free of Al2O3. CONSTITUTION: The Aluminum-free borosilicate glass is characterized in that it has chemical resistance and a composition, in percent by weight, based on oxide content, of: SiO2 of 60-78, B2O3 of 7-20, Li2O of 0-2, Na2O of 0-4, K2O of 3-12, MgO of 0-2, CaO of 0-2 with MgO + CaO being 0-3, BaO of 0-3, ZnO of 0-2, ZrO2 of 0.8-12, TiO2 of 0-10, CeO2 of 0-1, F¬- of 0-0.6 and optionally at least one refining agent in a standard amount for refining, wherein the aluminum-free borosilicate glass has a composition, in percent by weight, based on oxide content, of: SiO2 of 67-75, B2O3 of 9-18, Li2O of 0-1, Na2O of 0-3, K2O of 5-10 with Li2O + Na2O + K2O being 5.5-13.5, CaO of 0-1, BaO of 0-1, ZnO of 0-1, TiO2 of 0-1, ZrO2 of 0.8-10.5, CeO2 of 0-0.4, F¬- of 0-0.6 and optionally at least one refining agent in a standard amount for refining, and wherein the aluminum-free borosilicate glass has a composition, in percent by weight, based on oxide content, of: SiO2 of 68-74, B2O3 of 9-13, Li2O of 0-1, Na2O of 0-3, K2O of 5-10 with Li2O + Na2O + K2O being 5.5-13.5, ZrO2 of 3-7, CeO2 of 0-0.4, F¬- of 0-0.6 and optionally at least one refining agent in a standard amount for refining.
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