Submicrometer Transparent Alumina by Sinter Forging Seeded γ-Al2O3 Powders |
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Authors: | Oh-Hun Kwon C. Scott Nordahl Gary L. Messing |
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Affiliation: | Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 |
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Abstract: | Seeding boehmite with α-Al2O2, followed by calcination at 600°C, results in an agglomerated alumina powder (<53 μm) that can be sinter forged to full density at 1250°C. Compressive strains as high as ɛx=−0.9, and radial flow (ɛx= 1.0) during sinter forging remove large, interagglomerate pores. The fully dense alumina has a grain size of 0.4 pm and is visually transparent. It is proposed that deformation of dense agglomerates is the primary mecha- nism responsible for large pore elimination and compact densification. The sinter forging of sol-gel-derived alumina powders offers a new technology to prepare highly transparent, optical ceramics at lower temperatures than conventional routes. |
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