Impregnated cathode with composite top coat
US5936334A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 1994 |
| Grant date | Aug 10, 1999 |
| Priority date | — |
| Expiry date | Oct 31, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J1/28
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A cathode having a matrix body (1) impregnated with an alkaline earth compound, whose surface is provided with a top coat (2, 3, 4) comprising a high melting point metal, such as particularly tungsten, and scandium. A high emission at a low operating temperature and simultaneously a rapid recuperation after ion bombardment as well as a long lifetime are achieved in that the top coat comprises at least two layers of different composition, with a purely metallic layer (5, 6, 7) being provided on the impregnated matrix body (1), which layer comprises scandium and a high melting point metal such as particularly tungsten and/or rhenium, and in that a metallic layer of a high melting point metal such as particularly tungsten is provided as a sealing layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.