Unveiling exceptional sinterability of ultrafine α-Al2O3 nanopowders
Scalable pressureless sintering of nanocrystalline alumina (Al2O3) ceramics is a challenging problem with great scientific and technological interest. This challenge was addressed in our recent works utilizing ultrafine α-Al2O3 nanopowders with exceptional sinterability combined with two-step sinter...
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| Format: | Article |
| Language: | English |
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Elsevier
2021-07-01
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| Series: | Journal of Materiomics |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352847820305359 |
| _version_ | 1797718641578344448 |
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| author | Hongbing Yang Lu Li Yuanyuan Li Bing Shen Yueming Kang Libin Zhao Jiajie Li Yanhao Dong Jiangong Li |
| author_facet | Hongbing Yang Lu Li Yuanyuan Li Bing Shen Yueming Kang Libin Zhao Jiajie Li Yanhao Dong Jiangong Li |
| author_sort | Hongbing Yang |
| collection | DOAJ |
| description | Scalable pressureless sintering of nanocrystalline alumina (Al2O3) ceramics is a challenging problem with great scientific and technological interest. This challenge was addressed in our recent works utilizing ultrafine α-Al2O3 nanopowders with exceptional sinterability combined with two-step sintering technique. Here the sintering mechanism and kinetic parameters (grain boundary diffusivity and its activation energy) were analyzed from constant heating-rate sintering experiments by three different sintering models and compared with existing sintering data in the literature. We found that the low-temperature sintering of 4.7 nm α-Al2O3 nanopowders can be well explained by conventional sintering mechanism via grain boundary diffusion, with reasonable activation energy of 4–5 eV that is smaller than that of coarse Al2O3 powders and enhanced diffusivity. However, unphysically small activation energy could be obtained if an inappropriate model was used. Lastly, successful two-step sintering was demonstrated under different heating rates. Our work illustrates that the exceptional sinterability of ultrafine α-Al2O3 nanopowders are most likely contributed by small size (short diffusion distance), large surface area (large sintering driving force) and good dispersity rather than new sintering mechanism, and highlights the importance of fast firing and the non-equilibrium nature for the low-temperature sintering of such nanopowders. |
| first_indexed | 2024-03-12T08:53:19Z |
| format | Article |
| id | doaj.art-e0b359c80e774d2ca85a14735dbfd530 |
| institution | Directory Open Access Journal |
| issn | 2352-8478 |
| language | English |
| last_indexed | 2024-03-12T08:53:19Z |
| publishDate | 2021-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materiomics |
| spelling | doaj.art-e0b359c80e774d2ca85a14735dbfd5302023-09-02T16:13:47ZengElsevierJournal of Materiomics2352-84782021-07-0174837844Unveiling exceptional sinterability of ultrafine α-Al2O3 nanopowdersHongbing Yang0Lu Li1Yuanyuan Li2Bing Shen3Yueming Kang4Libin Zhao5Jiajie Li6Yanhao Dong7Jiangong Li8Institute of Materials Science and Engineering and MOE Key Laboratory for Special Functional Materials and Structure Design, Lanzhou University, Lanzhou, 730000, ChinaInstitute of Materials Science and Engineering and MOE Key Laboratory for Special Functional Materials and Structure Design, Lanzhou University, Lanzhou, 730000, ChinaInstitute of Materials Science and Engineering and MOE Key Laboratory for Special Functional Materials and Structure Design, Lanzhou University, Lanzhou, 730000, ChinaInstitute of Materials Science and Engineering and MOE Key Laboratory for Special Functional Materials and Structure Design, Lanzhou University, Lanzhou, 730000, ChinaInstitute of Materials Science and Engineering and MOE Key Laboratory for Special Functional Materials and Structure Design, Lanzhou University, Lanzhou, 730000, ChinaInstitute of Materials Science and Engineering and MOE Key Laboratory for Special Functional Materials and Structure Design, Lanzhou University, Lanzhou, 730000, ChinaInstitute of Materials Science and Engineering and MOE Key Laboratory for Special Functional Materials and Structure Design, Lanzhou University, Lanzhou, 730000, ChinaDepartment of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA; Corresponding author.Institute of Materials Science and Engineering and MOE Key Laboratory for Special Functional Materials and Structure Design, Lanzhou University, Lanzhou, 730000, China; Corresponding author.Scalable pressureless sintering of nanocrystalline alumina (Al2O3) ceramics is a challenging problem with great scientific and technological interest. This challenge was addressed in our recent works utilizing ultrafine α-Al2O3 nanopowders with exceptional sinterability combined with two-step sintering technique. Here the sintering mechanism and kinetic parameters (grain boundary diffusivity and its activation energy) were analyzed from constant heating-rate sintering experiments by three different sintering models and compared with existing sintering data in the literature. We found that the low-temperature sintering of 4.7 nm α-Al2O3 nanopowders can be well explained by conventional sintering mechanism via grain boundary diffusion, with reasonable activation energy of 4–5 eV that is smaller than that of coarse Al2O3 powders and enhanced diffusivity. However, unphysically small activation energy could be obtained if an inappropriate model was used. Lastly, successful two-step sintering was demonstrated under different heating rates. Our work illustrates that the exceptional sinterability of ultrafine α-Al2O3 nanopowders are most likely contributed by small size (short diffusion distance), large surface area (large sintering driving force) and good dispersity rather than new sintering mechanism, and highlights the importance of fast firing and the non-equilibrium nature for the low-temperature sintering of such nanopowders.http://www.sciencedirect.com/science/article/pii/S2352847820305359Nanocrystalline materialsSinteringAlumina (α-Al2O3)DiffusionActivation energy |
| spellingShingle | Hongbing Yang Lu Li Yuanyuan Li Bing Shen Yueming Kang Libin Zhao Jiajie Li Yanhao Dong Jiangong Li Unveiling exceptional sinterability of ultrafine α-Al2O3 nanopowders Journal of Materiomics Nanocrystalline materials Sintering Alumina (α-Al2O3) Diffusion Activation energy |
| title | Unveiling exceptional sinterability of ultrafine α-Al2O3 nanopowders |
| title_full | Unveiling exceptional sinterability of ultrafine α-Al2O3 nanopowders |
| title_fullStr | Unveiling exceptional sinterability of ultrafine α-Al2O3 nanopowders |
| title_full_unstemmed | Unveiling exceptional sinterability of ultrafine α-Al2O3 nanopowders |
| title_short | Unveiling exceptional sinterability of ultrafine α-Al2O3 nanopowders |
| title_sort | unveiling exceptional sinterability of ultrafine α al2o3 nanopowders |
| topic | Nanocrystalline materials Sintering Alumina (α-Al2O3) Diffusion Activation energy |
| url | http://www.sciencedirect.com/science/article/pii/S2352847820305359 |
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