Sputtered scandate coatings for dispenser cathodes and methods for making same
US5041757A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1990 |
| Grant date | Aug 20, 1991 |
| Priority date | — |
| Expiry date | Dec 21, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J9/047
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A low work function surface for a dispenser cathode structure. The cathode structure comprising a heater and an electron emitting surface substrate or core composed of a porous tungsten matrix impregnated with a barium containing impregnant distributed therethrough. The structure is made by a method in which a nanometer thick layer of scandium oxide is sputtered onto the outermost surface of the impregnated tungsten core, or substrate, and then oxidized by exposing the sputtered scandium oxide surface layer to an oxygen atmosphere. The oxidized surface layer is activated by turning on the heater, for example, to cause the release of a small portion of the barium in the barium-containing impregnant. Some of the released barium migrates into the scandium oxide surface layer to form a monolayer of barium oxide on at least a portion thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.