| 摘要 |
455,945. Treating glass surfaces. CORNING GLASS WORKS, Walnut Street, Corning, New York, U.S.A. Oct. 25, 1935, No. 29541. Convention date, Nov. 6, 1934. Addition to 455,460. [Class 56] [See also Group XL] Relates to a method of treating glass, described in the parent Specification, to prevent it from being discoloured by hot alkali vapour when used, for example, as the envelope of a sodium vapour arc lamp. According to the present invention, the glass is coated with a solution of a salt which is converted when the coated glass is heated to about 600‹ C., to a substantially transparent residue consisting wholly or mainly of alkali oxide. A solution in water of a decomposable salt of an alkali metal is atomized on to the warm glass, or the glass article is rinsed in the solution and dried, and the treated glass is then heated to 600‹-650‹ C. Preferably sodium hydroxide or sodium carbonate is used, but other alkali metal compounds, such as potassium iodide, sodium nitrate or sodium phosphate are suitable. |
