Ceramic discharge vessel having tungsten alloy feedthrough
View Patent ↗A tungsten alloy feedthrough for ceramic discharge vessels is used to form a hermetic seal with the ceramic body of the discharge vessel. The tungsten alloy comprises tungsten alloyed with a metal selected from titanium, vanadium or a combination thereof. The alloy may be formulated to have a coefficient of thermal expansion that closely matches that of the ceramic to prevent cracking. Preferably, the tungsten alloy contains from about 10 to about 35 wt. % of a metal selected from Ti, V, or a combination thereof.
1. A ceramic discharge vessel comprising: a ceramic body having at least one electrode assembly, the electrode assembly having a feedthrough portion sealed to the ceramic body, the feedthrough being comprised of a tungsten alloy wherein tungsten is alloyed with a metal selected from titanium, vanadium or a combination thereof and wherein the tungsten alloy contains from about 10 to about 35 wt. % of titanium, vanadium or a combination thereof.
2. The ceramic discharge vessel of claim 1 where in the ceramic body is comprised of polycrystalline alumina, sapphire, aluminum oxynitride or yttrium aluminum garnet.
3. The ceramic discharge vessel of claim 1 wherein the ceramic body has at least one capillary tube and the feedthrough is sealed to the capillary.
4. The ceramic discharge vessel of claim 1 wherein the feedthrough is sealed to the ceramic body with a frit material.
5. The ceramic discharge vessel of claim 1 wherein the ceramic body is composed of aluminum oxide and the tungsten alloy contains from 20 to 30 wt. % of titanium, vanadium or a combination thereof.
6. The ceramic discharge vessel of claim 5 wherein the tungsten alloy contains 25 wt. % titanium.
7. The ceramic discharge vessel of claim 5 wherein the tungsten alloy contains 22.5 wt. % vanadium.
8. The ceramic discharge vessel of claim 1 wherein the ceramic body is composed of aluminum oxynitride and the tungsten alloy contains from 10 to 20 wt. % of titanium, vanadium or a combination thereof.
9. The ceramic discharge vessel of claim 8 wherein the tungsten alloy contains 16.5 wt. % titanium.
10. The ceramic discharge vessel of claim 8 wherein the tungsten alloy contains 17 wt. % vanadium.
11. The ceramic discharge vessel of claim 1 wherein the ceramic body is composed of yttrium aluminum garnet and the tungsten alloy contains from about 20 to about 30 wt. % of titanium, vanadium or a combination thereof.
12. The ceramic discharge vessel of claim 11 wherein the tungsten alloy contains 26 wt. % titanium.
13. The ceramic discharge vessel of claim 11 wherein the tungsten alloy contains 25 wt. % vanadium.