Niobium-ceramic feedthrough assembly and ductility-preserving sealing process
US5057048A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 1989 |
| Grant date | Oct 15, 1991 |
| Priority date | — |
| Expiry date | Oct 23, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J61/368
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A process for sealing of niobium-ceramic through-wall assemblies for ceramic or metal vessels for high temperature and high pressure or vacuum applications, for example an electrical feedthrough and sealable fill opening in an alumina arc tube for a high intensity discharge (HID) lamp. The process produces a fritless hermetic seal while maintaining the ductility of the niobium components. The niobium-ceramic through-wall assembly includes an axially bored alumina or yttria sealing means having a ductile niobium throughpiece close fitted to and extending through the bore. The throughpiece is preferably essentially pure niobium, but may contain up to about 2% zirconium. The assembly is fired at about 1400.degree.-2000.degree. C. in a pure oxygen- and hydrogen-free (<5 ppm each) inert, preferably flowing, atmosphere or vacuum for a time sufficient to form a hermetic seal between the throughpiece and the sealing means. The fired assembly is then cooled to below 250.degree. C. while maintaining the pure inert atmosphere or vacuum. The end of the niobium throughpiece retains sufficient ductility after firing to permit pinching off of the end.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.