| 摘要 |
1487446 Making glass STANDARD TELEPHONES & CABLES Ltd 13 May 1975 20080/75 Heading C1M A method of making a glass comprises forming a melt of one or some of the constituents of the glass, or precursors thereof, which melt may include one or more phases, and adding the remaining constituent(s) by at least one chemical vapour deposition reaction. The reaction may be a hydrogen-free reaction between a halide and oxygen, and may be employed to deposit Al 2 O 3 , As 2 O 3 , B 2 O 3 or SiO 2 . More than one oxide may be deposited either successively or simultaneously (e.g. P 2 O 5 , B 2 O 3 or As 2 O 3 may be co-deposited with SiO 2 ). A melt 13 may be formed in a silica crucible 12 which is disposed inside silica jacket 11, through which jacket 11 coolant nitrogen gas passes. The melt 13 is heated by r.f. induction coil 10 (which is water-cooled), the r.f. field coupling with susceptor 15. Crucible 12, susceptor 15 and alumina supports 14, 16 are all mounted so as to be rotated and/or raised or lowered by means of silica support 17. The susceptor 15 may be of graphite (which may be coated with silicon, silica or silicon carbide) or of silicon. Susceptor 15 heats the melt until a temperature of, e.g., 800-1000‹ C. is reached, when the r.f. field may directly heat the melt 13, the susceptor 15 then being removed. The constituent(s) to be added are supplied by passing a reaction mixture (e.g. halide vapour entrained in oxygen) through pipe 19 to just above the melt surface, where the deposition reaction occurs, the reaction being induced thermally or by the action of the r.f. field. |
