Translucent Polycrystalline Alumina with Improved Resistance to Sodium Attack
| Autor: | Arlene Hecker, George C. Wei, David Goodman |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Gas-discharge lamp
Materials science Sodium Spinel technology industry and agriculture chemistry.chemical_element Mineralogy Sintering Sodium-vapor lamp engineering.material Microstructure law.invention chemistry Chemical engineering Aluminium law Materials Chemistry Ceramics and Composites engineering Grain boundary diffusion coefficient |
| Zdroj: | Journal of the American Ceramic Society. 84:2853-2862 |
| ISSN: | 1551-2916 0002-7820 |
| DOI: | 10.1111/j.1151-2916.2001.tb01105.x |
| Popis: | Reaction of sodium with polycrystalline alumina (PCA) arc tubes in high-pressure sodium lamps can limit lamp performance. The rate of degradation depends on the grain-boundary diffusion of a reaction product, aluminum, through the PCA wall. The effects of sintering aids and other dopants on the sodium resistance of PCA are investigated via accelerated lamp tests and microstructural analyses. Key material parameters for sodium resistance are the spinel (MgAl2O4) second phase and the grain-boundary MgO level. Eliminating spinel in the sintered body, doping with tetravalent cations to charge-compensate the Mg2+ solutes, and creating a second phase to absorb MgO in situ, significantly improve the resistance of PCA to sodium attack. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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