Effect of oxygen content on bending strength and thermal conductivity of aluminum nitride ceramics
AlN ceramic powders with the different oxygen contents were prepared by the carbon-thermal reduction method through controlling the carbon removal process, using Al2O3 powders and carbon black as raw materials. The mass fraction of oxygen in high-oxygen AlN powders was 0.9%, and that in low-oxygen A...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | Chinese |
| Published: |
Editorial Office of Powder Metallurgy Technology
2025-06-01
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| Series: | Fenmo yejin jishu |
| Subjects: | |
| Online Access: | https://pmt.ustb.edu.cn/article/doi/10.19591/j.cnki.cn11-1974/tf.2024010006 |
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| Summary: | AlN ceramic powders with the different oxygen contents were prepared by the carbon-thermal reduction method through controlling the carbon removal process, using Al2O3 powders and carbon black as raw materials. The mass fraction of oxygen in high-oxygen AlN powders was 0.9%, and that in low-oxygen AlN powders was 0.6%. The AlN ceramic samples were prepared using these high-oxygen and low-oxygen AlN ceramic powders. The bending strength and thermal conductivity of the AlN ceramics were tested within the range of 77～350 K by the three-point bending method and the 3ω method. The influence of oxygen content on the bending strength and thermal conductivity of AlN ceramics was discussed and compared with those of Al2O3 ceramics and Si3N4 ceramics. The results show that the content of the second phases is relatively high in the high-oxygen AlN ceramic samples, while it is relatively low in the low-oxygen AlN ceramic samples. The second phases inhibit the growth of AlN grains and play a role in fine-grained strengthening. However, the presence of the second phases reduces the free path of phonons and the thermal conductivity. Within the experimental temperature range, the bending strength of high-oxygen AlN ceramic samples is higher than that of low-oxygen AlN ceramic samples, and the thermal conductivity is lower than that of low-oxygen AlN ceramic samples. The room-temperature bending strength of AlN ceramics is slightly higher than that of Al2O3 ceramics, but not as good as that of Si3N4 ceramics. The room-temperature thermal conductivity of AlN ceramics is higher than that of Al2O3 ceramics and Si3N4 ceramics, reaching 200 W·m−1·K−1. Meanwhile, the AlN ceramics can maintain high thermal conductivity and relatively high bending strength at low temperatures. Therefore, compared with Al2O3 ceramics and Si3N4 ceramics, the AlN ceramics have a wider range of low-temperature applications. |
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| ISSN: | 1001-3784 |