Effect of SiO2 addition on Si3N4 ceramics prepared by rapid nitridation and post-sintering route
| Autor: | Jun-Jie Yu, Wei-Ming Guo, Hua-Tay Lin, Ling-Yong Zeng |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Toughness Materials science Process Chemistry and Technology Metallurgy Sintering 02 engineering and technology Gas pressure sintering 021001 nanoscience & nanotechnology Microstructure 01 natural sciences Grain size Surfaces Coatings and Films Electronic Optical and Magnetic Materials Catalysis Chemical engineering Phase (matter) visual_art 0103 physical sciences Materials Chemistry Ceramics and Composites visual_art.visual_art_medium Ceramic 0210 nano-technology |
| Zdroj: | Ceramics International. 43:13901-13906 |
| ISSN: | 0272-8842 |
| Popis: | Effects of SiO 2 content and Y 2 O 3 :Al 2 O 3 mass ratio on phase compositions, densification, microstructures and mechanical properties of sintered reaction-bonded Si 3 N 4 ceramics prepared by rapid nitridation of Si powders using TiO 2 as catalyst and subsequent gas pressure sintering were investigated. The low Y 2 O 3 :Al 2 O 3 ratio could reduce the adverse effect of high SiO 2 content on densification and microstructure by the formation of O′-Sialon phase. The bulk density of the ceramics with low Y 2 O 3 :Al 2 O 3 ratio was higher than that with high Y 2 O 3 :Al 2 O 3 ratio, especially at high SiO 2 content. Irrespective of Y 2 O 3 :Al 2 O 3 ratio, the increasing SiO 2 content led to microstructural coarsening, but the ceramics with high Y 2 O 3 :Al 2 O 3 ratio and SiO 2 content contained more large-elongated grains. The hardness and toughness of the ceramics with low Y 2 O 3 :Al 2 O 3 ratio slightly decreased with increasing SiO 2 content, and the strength basically had no change. Whereas the mechanical properties of the ceramics with high Y 2 O 3 :Al 2 O 3 ratio obviously decreased with increasing SiO 2 content due to the markedly decreased bulk density and increased grain size. The present results suggested the low Y 2 O 3 :Al 2 O 3 ratio would contribute to the improvement of mechanical properties of SRBSN ceramics prepared from low-grade Si powers containing high content of SiO 2 . |
| Databáze: | OpenAIRE |
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