Method of making a high current density long life cathode
US4078900A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 1977 |
| Grant date | Mar 14, 1978 |
| Priority date | — |
| Expiry date | Jun 22, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J23/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A high current density long life cathode for use in high power microwave e applications is made by: machining a porous tungsten pellet with copper in its pores to the desired cathode shape to form the emitting surface of the cathode and cleaning the porous pellet ultrasonically in trichloroethylene, then acetone, and then methanol; firing the tungsten pellet at about 1800.degree. C in a reducing atmosphere; etching the tungsten pellet ultrasonically in a solution of 50 parts of concentrated nitric acid in 50 parts of water; ultrasonically cleaning the tungsten pellet for about five minutes in an aqueous alkaline solution; cleaning the tungsten pellet in hot deionized water and then air drying the tungsten pellet in an oven for five minutes at about 150.degree. C; refiring the tungsten pellet in a reducing atmosphere at about 1800.degree. C; impregnating the porous tungsten pellet with a mixture of Ba.sub.3 WO.sub.6, Ba.sub.2 SrWO.sub.6 and ZrH.sub.2 in a nonreducing, nonoxidizing atmosphere at about 1900.degree. C to 2000.degree. C; and firing the impregnated tungsten pellet in a reducing atmosphere of dry hydrogen at about 1840.degree. C for about 2 to 5 minutes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.