| 摘要 |
<p>1,231,517. Glass compositions; glass to metal seals. GENERAL ELECTRIC CO. 21 Feb., 1969 [23 Feb., 1968], No. 9576/69. Heading C1M. [Also in Division G2] Glass used to make photoflash lamp bulbs comprises essentially by weight, 60-75% SiO 2 , 10-25% B 2 O 3 , 1-10% Al 2 O 3 , 4-10% total alkali oxides and 0-5% BaO, and has a coefficient of linear thermal expansion of 40 x 10<SP>-7</SP> to 50 x 10<SP>-7</SP> per ‹C. in the temperature range 0-300‹ C. The alkali oxides are preferably selected from sodium, potassium and lithium oxides. Residual fluxes, impurities and refining agents such as As 2 O 3 may be present. Lead in wires of iron-cobalt-nickel alloys of similar coefficients of linear thermal expansion are sealed to the lamp by a bead of the same glass.</p> |
