| 摘要 |
1515827 Glass ceramics CORNING GLASS WORKS 18 March 1977 [25 May 1976] 11553/77 Heading C1M A transparent glass-ceramic article wherein beta-quartz solid solution constitutes the predominant crystal which article exhibits a coefficient of thermal expansion over the range of from room temperature to 600‹C of less than 10 Î 10<SP>-7</SP>/‹C and an infra-red transmittance at a wave-length of 2À5 microns through a polished plate of 3 mm thickness in excess of 75% comprises, by weight on the oxide basis, 2À5-3À5% Li 2 O,1À5-2À5% MgO, 1-2% ZnO, 17À75-20% Al 2 O 3 , 67-70% SiO 2 , 2-4À5% TiO 2 and 1-2% ZrO 2 , the balance, if any, consisting of one or more compatible constituents. The article may additionally contain BaO and conventional glass colouring agents such as Co 3 O 4 , NiO, Cr 2 O 3 , Fe 2 O 3 , MnO 2 , N 2 O 5 and Cu 2 O as well as As 2 O 3 . It has particular use in culinary applications and is suitably produced by exposing the glass to a temperature of 750-850‹C to cause the development of nuclei therein prior to exposing to a temperature of 850-950‹C.
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