| 摘要 |
<p>1,143,228. Strengthening glass by coating. PHILIPS GLOEILAMPENFABRIEKEN N.V. 9 Dec., 1966 [14 Dec., 1965], No. 55205/66. Heading C1M. To strengthen glass objects, two layers of glaze or enamel are applied, the first having a lower co-efficient of expansion than the glass, the second having one not more than 50+10<SP>-7</SP> higher than the first and the second layer also has a lower softening temperature than the first layer and has a thickness not more than 1À5 times that of the first layer. The glass base is preferably that disclosed in Specification 1,051,703, a particular example used having in per centages by weight SiO 2 48À6; Al 2 O 3 26À3; Na 2 O 25À1. The thickness of the first layer is preferably for 50Á to 200Á, and is of a crystalline glaze with composition ZnO 67À1; B 2 O 3 29À0; SiO 2 3À9. The top glaze is ZnO 8; PbO 56; Al 2 O 3 3; B 2 O 3 18; SiO 2 15 which may have (in gms. to 100 gms. of the glaze) Fe 3 O 4 4; MaO 2 6 to give a brown glaze.</p> |
