Method of reducing magnesium loss during sintering of aluminum oxide articles
US7481963B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 28, 2005 |
| Grant date | Jan 27, 2009 |
| Priority date | — |
| Expiry date | Oct 4, 2027 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2235/94
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method for reducing the loss of magnesium during the sintering of aluminum oxide articles, such as ceramic discharge vessels for lighting applications. Magnesium oxide is added to aluminum oxide articles to control grain growth during sintering, but the sintering causes magnesium loss from the article. In order to address this problem, one or more aluminum oxide articles that are enriched in magnesium oxide are added to the sintering furnace to stem the loss of magnesium oxide in the remaining articles. The enriched aluminum oxide article is made by soaking a porous aluminum oxide article in an aqueous solution of magnesium nitrate and heating the porous article to convert the magnesium nitrate to magnesium oxide. The enriched articles may then be added in one or several locations to the sintering furnace, where the magnesium from the enriched articles is released to suppress the magnesium loss.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.