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Journal of the Korean Ceramic Society 1999;36(1): 97. |
| 성형미세구조가 반응소결 탄화규소체의 소결미세구조 및 기계적 특성에 미치는 영향 |
| 박현철, 김재원1, 백운규1, 최성철 |
한양대학교 공과대학 무기재료공학과
1창원대학교 공과대학 세라믹공학과 |
| Effect of Green Microstructure on Sintered Microstructure and Mechanical Properties of Reaction-Bonded Silicon Carbide |
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| ABSTRACT |
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In the binary system of SiC and carbon, porosity and pore size distribution of green body was controlled by varying pH, by the addition of polyelectrolyte dispersants, and by using different particle size of starting powders. The preforms having different green microstructure were fabricated by slip casting from suspensions having different dispersion condition. The reaction bonding process was carried out for these preforms. The condition of reaction bonding was 1600$^{circ}C$ and 20 min. under vacuum atmosphere. The analyses of optical and SEM were studied to investigate the effect of green microstructure on that of reaction bonded silicon carbide and subsequently the mechanical properties of sintered body was investigated. Different green microstructures were obtained from suspensions having different dispersion condition. It was found that the pore size could be remarkably reduced for a fine SiC(0.5$mutextrm{m}$). The bimodal microstructure was not found in the present study, which is frequently observed in the typical reaction bonded silicon carbide. It is considered that the ratio between SiC and C was responsible for the formation of bimodal microstructure. For the preform fabricated from the well dispersed suspension, the 3-point bending strength of reaction-bonded silicon carbide was 310${pm}$40 MPa compared to the specimen fabricated from relatively agglomerated particles having lower value 260${pm}$MPa. |
| Key words:
Silicon, Silicon carbide, Green microstructure, Dispersion, Reaction-bonding, Bimodal microstructure |
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