High-Pressure Sintering of Nanocrystalline γAl2O3 |
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| Authors: | Rajiv S. Mishra,&# ,Charles E. Lesher,Amiya K. Mukherjee |
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| Affiliation: | Department of Chemical Engineering and Materials Science and Department of Geology, University of California, Davis, California 95616 |
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| Abstract: | High-pressure sintering of nanocrystalline γ-A12O3 has been studied over a temperature range of 923-1323 K and at a pressure of 1 GPa. The γ-Al2O3 to α-Al2O3 transformation temperature changed from 1473 K without pressure to ∼1023 K at 1 GPa. Full density was obtained at 1273 and 1323 K in 10 min. The microhardness value of fully dense α-alumina with a grain size of 142 nm was found to be 25.3 ± 0.8 GPa. The Hall-Petch slope for the very fine grain size range is different from that of the coarse-grained alumina. |
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