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Improvement of translucency in Al2O3 ceramics by two-step sintering technique
Translucent polycrystalline Al2O3 ceramics are used in high-pressure sodium lamp envelopes. Pure, 140, 500, and 2500 ppm MgO-doped Al2O3 specimens were sintered at 1700 C in vacuum with and without pre-sintering heat treatment at 800 C for 50 h in air. Pre-sintering heat treatment improved the trans...
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Published in: | Journal of the European Ceramic Society 2007, Vol.27 (13-15), p.3629-3632 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Translucent polycrystalline Al2O3 ceramics are used in high-pressure sodium lamp envelopes. Pure, 140, 500, and 2500 ppm MgO-doped Al2O3 specimens were sintered at 1700 C in vacuum with and without pre-sintering heat treatment at 800 C for 50 h in air. Pre-sintering heat treatment improved the transmittance in the visible (400-700 nm) range significantly. This enhanced transmittance was explained in terms of the removal of residual pores and the homogenisation of the microstructure due to the lowering of the boundary mobility as a result of MgO addition and the suppression of local densification through a pre-coarsening step. 11 refs. |
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ISSN: | 0955-2219 1873-619X |
DOI: | 10.1016/j.jeurceramsoc.2007.02.002 |