| 摘要 |
1,181,581. Ion exchange treatment of glass. OWENS-ILLINOIS Inc. 23 Feb., 1967 [23 Feb., 1966; 23 Dec., 1966], No. 8671/67. Heading C1M. A glass containing at least 2% by weight expressed as soda mole equivalent of an alkali metal oxide is treated by (1) applying to the article's surface a solution or suspension, in water and/or an organic solvent, of at least one salt of a different alkali metal to form a substantially continuous layer of material consisting of or containing the salt, (2) maintaining at a temperature above the boiling point of the water and/or organic solvent, e.g. 200-760‹ C., the salt-containing material being solid at said temperature, so that ion exchange between the alkali metal in the glass and that of the solid salt occurs to give a stress in the surface of the glass, but for insufficient time to allow stress relaxation to occur, and (3) cooling to a temperature at which ion exchange does not occur, the layer of material and salt being subsequently removable from the glass. The alkali-metal ions in the glass may be exchanged for larger or smaller ions. The salt applied may be a carbonate; K2HPO4 may also be used. The salt layer may be removed by washing with dilute nitric acid. Many examples of glasses which may be treated are given, including some examples of crystallizable glass. The layer may include salts to colour the glass, for example, chlorides, carbonates and sulphates of Co, Fe, Ni, which will diffuse into the glass surface. |
