Porous Silicon Nitride Ceramics Prepared by Reduction–Nitridation of Silica |
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| Authors: | Shao-Yun Shan Jian-Feng Yang Ji-Qiang Gao Wen-Hui Zhang Zhi-Hao Jin Rolf Janssen Tatsuki Ohji |
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| Affiliation: | State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China; Advanced Ceramics Group, Technische Universität Hamburg-Harburg, D-21073 Hamburg, Germany; Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Nagoya 463-8560, Japan |
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| Abstract: | A new method for preparing porous silicon nitride ceramics with high porosity had been developed by carbothermal reduction of die-pressed green bodies composed of silicon dioxide, carbon, sintering additives, and seeds. The resultant porous silicon nitride ceramics showed fine microstructure and uniform pore structure. The influence of SiO2 particle size and sintering process (sintering temperature and retaining time) on the microstructure of sintering bodies was analyzed. X-ray diffractometry demonstrated the formation of single-phase β-Si3N4 via the reaction between silicon dioxide and carbon at high temperature. SEM analysis showed that pores were formed by the banding up of rod-like β-Si3N4 grains. Porous Si3N4 ceramics with a porosity of 70–75%, and a strength of 5–8 MPa, were obtained. |
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