Preparation of Both Reactive α-Si3N4 and SiC Mixed Powder in Flame-Isolation Nitridation Shuttle Kiln
| Periodical | Key Engineering Materials (Volumes 512 - 515) |
|---|---|
| Main Theme | High-Performance Ceramics VII |
| Edited by | Wei Pan and Jianghong Gong |
| Pages | 17-23 |
| DOI | 10.4028/www.scientific.net/KEM.512-515.17 |
| Citation | Xiao Yan Zhu et al., 2012, Key Engineering Materials, 512-515, 17 |
| Online since | June, 2012 |
| Authors | Xiao Yan Zhu, Yong Li, Jia Ping Wang, Ya Wei Zhai, Jun Bo, Jian Fang Zhang |
| Keywords | Electric Kiln, Flame-Isolation Nitridation Shuttle Kiln, Temperature Field Uniformity, α-Si3N4, β-Si3N4 |
| Price | US$ 28,- |
α-Si3N4 possesses excellent sintering activity, which is used to prepare high performance Si3N4-based ceramics and composite refractory. Si3N4 powder is always synthesized by nitriding silicon in controlled-atmosphere furnace whose furnace volume is very small(effective volume: 1840×1420×1660mm), the extreme reaction heat is difficult to diffuse, which leads to high reaction temperature and conversion of α-Si3N4 to β-Si3N4, thus α-Si3N4 is difficult to be obtained in controlled-atmosphere furnace. While flame-isolation nitridation shuttle kiln has much larger furnace volume to conduct reaction heat (effective volume: 11500×4190×1684mm), so it owns homogeneous temperature field and stable low-temperature environment which benefits the preparation of α-Si3N4. Thermodynamic analysis of Si-N system is shown that Si3N4 can be formed by two formats: direct nitridation of Si(s) and indirect nitridation of SiO(g); to ensure completely nitridation, the particle size of silicon powder should be less than 88μm. With reclaimed powder from polysilicon cutting slurry as starting materials, both reactive α-Si3N4 and SiC mixed powder were successfully prepared in flame-isolation nitridation shuttle kiln. Because of the gas-gas reaction between SiO(g) and N2(g), α-Si3N4 is fiber-like and in favor of processing high quality Si3N4-based materials.
