Method of making a ruggedized high current density cathode
US4236287A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 25, 1979 |
| Grant date | Dec 2, 1980 |
| Priority date | — |
| Expiry date | Jun 25, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J9/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A high current density cathode capable of operating at current densities of A/cm.sup.2 to 30A/cm.sup.2 in the temperature range of 900 degrees C. to 1125 degrees C. is prepared by machining a porous high purity tungsten pellet containing copper in its pores and also containing about 0.6 to 2 weight percent of an activator to the desired cathode shape without reducing the pores of the emitter pellet. The pellet is then fired at 1800 degrees C. in a non-oxidizing atmosphere to remove the copper filler material. The pellet is then impregnated with Ba.sub.5 Sr(WO.sub.6)2 at a temperature of 1900 degrees C. in a dry inert gas atmosphere and the impregnated emitter then fired in dry hydrogen atmosphere at about 1840 degrees C. for about 2.5 to 5 minutes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.