Claims
- 1. A low work function scandate surface coating for a dispenser cathode structure containing an outer surface substrate composed of porous tungsten impregnated with a barium containing impregnant distributed therethrough, the surface coating comprising a 1 to 30 nanometer thick layer of scandium oxide deposited onto the outermost portion of the substrate, the scandium oxide surface coating further comprising an activating amount of barium oxide.
- 2. The cathode coating of claim 1 wherein the scandium oxide coating layer has a thickness in the range between about 5 and 20 nanometers.
- 3. The cathode coating of claim 1 wherein the scandium oxide coating layer has a thickness in the range between about 8 and 15 nanometers.
- 4. The cathode coating of claim 1, wherein the scandium oxide coating layer has a thickness in the range between about 10 and 12 nanometers.
- 5. The cathode coating of claim 1 wherein the surface coating is deposited by sputtering.
- 6. The cathode coating of claim 1, wherein the porous tungsten substrate has a density of 80.+-.10 percent of its theoretical density and the barium containing impregnant is barium-calcium aluminate.
Parent Case Info
This is a division of application Ser. No. 632,194, filed Dec. 21, 1990, now U.S. Pat. No. 5,041,757.
US Referenced Citations (6)
Divisions (1)
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Number |
Date |
Country |
Parent |
632194 |
Dec 1990 |
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