| 摘要 |
A surface crystallizable glass consists essentially of, in weight per cent, 54-65% SiO2, 17-35% Al2O3, 3-9% Li2O, 2-6% MgO, and 2-11% Na2O, 2-11% K2O, 1-11% P2O5, a mixture of Na2O and K2O not exceeding 11%, a mixture of Na2O + P2O5 not exceeding 12%, a mixture of K2O + P2O5 not exceeding 12% or a mixture of Na2O + K2O + P2O5 not exceeding 12%. Other compatible oxides may be present up to a total maximum of 15% by weight such as the oxides of lead, titanium and boron. The titanium dioxide should be present in amounts of less than 2.5%, the boric oxide less than 5% and litharge less than 10%. |
