Translucent polycrystalline alumina and method of making same
AssigneeOsram Sylvania Inc.
InventorsGeorge Wei, Arlene Hecker, David Goodman
Life of this patent
Estimating the term…
Abstract
An optically translucent polycrystalline alumina sintered body consists essentially of alumina, magnesia, terbia and, optionally, yttria. The magnesia is present in an amount of about 0.020 wgt. percent and the terbia is present in an amount of from about 0.005 to 0.060 wgt. percent. The yttria is present in an amount up to about 0.035 wgt. percent.
Claims4
An arc tube for a high pressure sodium lamp, said arc tube consisting essentially of:
- magnesia in an amount of about 0.020 to 0.050 wgt. percent;
- terbium oxide;
- and up to about 0.035 wgt. percent yttria;
- balance alumina, the terbium oxide being present in an effective amount of about 0.005 to about 0.060 to substantially cause the formation of terbium aluminate second phase during lamp manufacture.
An optically translucent polycrystalline alumina sintered body consisting essentially of alumina, magnesia, terbia and, optionally, yttria, said magnesia being present in an amount of about 0.020 to 0.050 wgt. percent;
- said terbia being present in an amount of from about 0.005 to about 0.060;
- and said yttria being present in an amount up to about 0.035 wgt. percent.
Dependencies are inferred from the claim text.