| 摘要 |
<p>Flat glass which has been manufactured in ribbon form on a bath of molten tin is treated by maintaining the ribbon at an elevated temperature, e.g. 400 DEG to 650 DEG C., particularly the surface which has been in contact with the molten tin, under conditions which prevent oxidation of that surface which has been in contact with the molten tin. The glass may be maintained in an atmosphere of nitrogen or other inert gas such as argon or helium, but the preferred gas is a mixture of nitrogen and about 5% hydrogen. Alternatively the glass may be passed through a chamber substantially evacuated preferably to give an atmosphere having a pressure of less than 1 mm. of Hg for a period of time of up to thirty minutes. Alternatively the glass surface which has been in contact with the molten tin is held in contact with, or the glass passed through, a liquid medium such as molten bismuth or a molten mixture of sodium chloride, potassium chloride and lithium chloride. Treatment is preferably in a chamber between the end of the molten metal bath and the annealing lehr.</p> |
