Effects of Sintering Processes on Microstructure Evolution, Crystallite, and Grain Growth of MoO<sub>2</sub> Powder
MoO<sub>2</sub> micro-powders with a mean pore size of 3.4 nm and specific surface area of 2.5 g/cm<sup>3</sup> were compacted by dry pressing, then pressureless sintered at a temperature of 1000–1150 °C for 2 h or for a sintering time of 0.5–12 h at 1050 °C in an N<sub>...
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MDPI AG
2023-08-01
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| Series: | Crystals |
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| author | Jongbeom Lee Jinyoung Jeong Hyowon Lee Jaesoung Park Jinman Jang Haguk Jeong |
| author_facet | Jongbeom Lee Jinyoung Jeong Hyowon Lee Jaesoung Park Jinman Jang Haguk Jeong |
| author_sort | Jongbeom Lee |
| collection | DOAJ |
| description | MoO<sub>2</sub> micro-powders with a mean pore size of 3.4 nm and specific surface area of 2.5 g/cm<sup>3</sup> were compacted by dry pressing, then pressureless sintered at a temperature of 1000–1150 °C for 2 h or for a sintering time of 0.5–12 h at 1050 °C in an N<sub>2</sub> atmosphere. Then, their microstructure evolution for morphology, crystallite, and grain growth were investigated. By sintering at a certain temperature and times, the irregular shape of the MoO<sub>2</sub> powders transformed into an equiaxed structure, owing to the surface energy, which contributed to faster grain growth at the initial stage of sintering. The crystallite and grain sizes exponentially increased with the sintering time, and the growth exponent, <i>n</i>, was approximately 2.8 and 4, respectively. This indicates that the crystallite growth is governed by dislocation-mediated lattice diffusion, and the grain growth is determined by surface diffusion-controlled pore mobility. The increase in sintering temperature increased both crystallite and grain size, which obeyed the Arrhenius equation, and the activation energies were determined to be 95.65 and 76.95 kJmol<sup>−1</sup> for crystallite and grain growths, respectively. |
| first_indexed | 2024-03-10T22:54:13Z |
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| id | doaj.art-6ce551e34f2b4772b2c5f8a303cd80ca |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-10T22:54:13Z |
| publishDate | 2023-08-01 |
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| record_format | Article |
| series | Crystals |
| spelling | doaj.art-6ce551e34f2b4772b2c5f8a303cd80ca2023-11-19T10:08:57ZengMDPI AGCrystals2073-43522023-08-01139131110.3390/cryst13091311Effects of Sintering Processes on Microstructure Evolution, Crystallite, and Grain Growth of MoO<sub>2</sub> PowderJongbeom Lee0Jinyoung Jeong1Hyowon Lee2Jaesoung Park3Jinman Jang4Haguk Jeong5Industrial Materials Processing R&D Group, Korea Institute of Industrial Technology, Incheon 21999, Republic of KoreaIndustrial Materials Processing R&D Group, Korea Institute of Industrial Technology, Incheon 21999, Republic of KoreaThin Film Materials R&D Team, LT Metal. Co., Ltd., Incheon 21697, Republic of KoreaThin Film Materials R&D Team, LT Metal. Co., Ltd., Incheon 21697, Republic of KoreaIndustrial Materials Processing R&D Group, Korea Institute of Industrial Technology, Incheon 21999, Republic of KoreaIndustrial Materials Processing R&D Group, Korea Institute of Industrial Technology, Incheon 21999, Republic of KoreaMoO<sub>2</sub> micro-powders with a mean pore size of 3.4 nm and specific surface area of 2.5 g/cm<sup>3</sup> were compacted by dry pressing, then pressureless sintered at a temperature of 1000–1150 °C for 2 h or for a sintering time of 0.5–12 h at 1050 °C in an N<sub>2</sub> atmosphere. Then, their microstructure evolution for morphology, crystallite, and grain growth were investigated. By sintering at a certain temperature and times, the irregular shape of the MoO<sub>2</sub> powders transformed into an equiaxed structure, owing to the surface energy, which contributed to faster grain growth at the initial stage of sintering. The crystallite and grain sizes exponentially increased with the sintering time, and the growth exponent, <i>n</i>, was approximately 2.8 and 4, respectively. This indicates that the crystallite growth is governed by dislocation-mediated lattice diffusion, and the grain growth is determined by surface diffusion-controlled pore mobility. The increase in sintering temperature increased both crystallite and grain size, which obeyed the Arrhenius equation, and the activation energies were determined to be 95.65 and 76.95 kJmol<sup>−1</sup> for crystallite and grain growths, respectively.https://www.mdpi.com/2073-4352/13/9/1311MoO<sub>2</sub>sinteringXRDSEMmorphologycrystallite |
| spellingShingle | Jongbeom Lee Jinyoung Jeong Hyowon Lee Jaesoung Park Jinman Jang Haguk Jeong Effects of Sintering Processes on Microstructure Evolution, Crystallite, and Grain Growth of MoO<sub>2</sub> Powder Crystals MoO<sub>2</sub> sintering XRD SEM morphology crystallite |
| title | Effects of Sintering Processes on Microstructure Evolution, Crystallite, and Grain Growth of MoO<sub>2</sub> Powder |
| title_full | Effects of Sintering Processes on Microstructure Evolution, Crystallite, and Grain Growth of MoO<sub>2</sub> Powder |
| title_fullStr | Effects of Sintering Processes on Microstructure Evolution, Crystallite, and Grain Growth of MoO<sub>2</sub> Powder |
| title_full_unstemmed | Effects of Sintering Processes on Microstructure Evolution, Crystallite, and Grain Growth of MoO<sub>2</sub> Powder |
| title_short | Effects of Sintering Processes on Microstructure Evolution, Crystallite, and Grain Growth of MoO<sub>2</sub> Powder |
| title_sort | effects of sintering processes on microstructure evolution crystallite and grain growth of moo sub 2 sub powder |
| topic | MoO<sub>2</sub> sintering XRD SEM morphology crystallite |
| url | https://www.mdpi.com/2073-4352/13/9/1311 |
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