摘要 |
<p>An arc discharge lamp is provided using sealing compositions comprising mainly Al2O3-SiO2-Mg0 selected from compositions lying within the area ABCDEFGH on the undernoted ternary phase diagram and methods of using these are described. Preferred compositions include between 15 to 28% by weight of MgO and 13 to 21% by weight of A1203 since these have lower melting points than others in the group. The sealing compositions are used to seal end closure members of alumina or cermet to ceramic arc tubes for use in discharge lamps. The compositions are selected to have linear expansion co-ef- ficients compatible with the materials of the end closures and arc tubes. The methods described give sealing times of between 3 and 4 minutes.</p> |