| 摘要 |
Aluminosilicate glasses containing BaO and CaO are provided having combined high softening points along with exceptionally low liquidus temperatures. These glasses are within the following compositional limits in percent by weight: } Percentage }Oxides Range }SiO2 55-68 }Al2O3 15-18 }CaO 7-13 }BaO 6-16 } except for incidental impurities, residual fluxes and refining agents. The weight ratio of Al2O3 to combined weight ratio of CaO and BaO in the present glass composition is maintained in the range 0.6:1 to 1:1. Such glasses provide an improved hermetic seal for high temperature lamp envelopes. |
