| 摘要 |
1,157,460. Glass compositions. OWENSILLINOIS, Inc. 13 July, 1967 [13 July, 1966], No. 32183/67. Heading C1M. Partially crystalline ceramic glass articles are produced by making a thermally crystallizable glass melt containing the components in percentage by weight:-SiO 2 60-66, Al 2 O 3 12-18, CaO 4-7, MgO 4-7, Li 2 O 1À5-4, TiO 2 1À5-6, ZrO 2 0À5-3, ZnO 2-5, (MgO + CaO) 8-13, at least 90% by weight of the glass consisting of SiO 2 + Al 2 0 3 + Li 2 O + Mg O + CaO + TiO 2 + ZrO 2 + ZnO, forming a glass article of predetermined size and shape from the glass melt, and treating the article in an initial low temperature heat treatment to form many nuclei or crystallites, and thereafter heating at a higher temperature to complete crystallization to the desired degree. Generally the lower treatment temperature ranges from 30‹ F. below to 300‹ F. above the annealing point of the particular glass used, and the upper treatment temperature ranges from 1500‹ to 2000‹ F., the article generally being kept at the lower temperature for a time ranging from ¢ to 6 hours, and at the higher temperature for a time ranging from to 6 hours, In addition to the above essential ingredients the crystallizable glass composition may also contain other compatible glass forming components, for example up to 3% BaO or SrO, up to 4% B 2 0 3 or P 2 0 5 or F, and small amounts of colorants such as NiO or CoO. |
