Method of treating tungsten cathodes
US4836816A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 6, 1988 |
| Grant date | Jun 6, 1989 |
| Priority date | — |
| Expiry date | May 6, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J9/042
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method of treating a tungsten cathode that is comprised of coating the surface of the tungsten cathode with a triple carbonate suspension. The coated tungsten cathode is placed in a heated oxidizing environment (e.g., air, oxygen, or carbon dioxide) and heated for a sufficient amount of time in order to form a diffuse coating of triple carbonates and tungsten oxide. Thereafter, the triple carbonates are reduced to their respective oxides by passing heater current through the tungsten cathode. When used in conjunction with the manufacture of a fluorescent lamp, the formation of this diffuse coating of carbonates enhances the chances of forming barium tungstate during the cathode activation process. As a result, the life of the fluorescent lamp is increased and the amount of phosphor darkening is reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.