Novel silicothermic reduction method to obtain Si3N4 ceramics with enhanced thermal conductivity and fracture toughness
| Autor: | Yongfeng Xia, Yu-Ping Zeng, Dongxu Yao, Jinwei Yin, Weide Wang, Kaihui Zuo, Hanqin Liang |
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| Rok vydání: | 2021 |
| Předmět: |
010302 applied physics
Materials science Sintering 02 engineering and technology 021001 nanoscience & nanotechnology Microstructure 01 natural sciences Grain growth Fracture toughness Thermal conductivity visual_art Phase (matter) 0103 physical sciences Materials Chemistry Ceramics and Composites visual_art.visual_art_medium Ceramic Composite material 0210 nano-technology Porosity |
| Zdroj: | Journal of the European Ceramic Society. 41:1735-1738 |
| ISSN: | 0955-2219 |
| Popis: | The development of bimodal microstructure in Si3N4 ceramics was crucial to the thermal conductivity and fracture toughness. Silicothermic reduction treatment (SRT) combined with gas-pressure sintering (GPS) were conducted to promote the development of bimodal microstructure. SRT leads to a reduced amount of liquid phase and an increased N/O ratio in the liquid phase, resulting in a faster phase transformation rate relative to densification and a promoted grain growth during GPS. Consequently, large β-Si3N4 grains were well developed in a porous fine β-Si3N4 matrix skeleton without grain impingement. Dense Si3N4 ceramics with exaggerated bimodal microstructure was obtained after sintered at 1900 °C for 4 h. Summarily, the addition of Si leads to the improvement of thermal conductivity and fracture toughness simultaneously. |
| Databáze: | OpenAIRE |
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