DOI QR코드

DOI QR Code

Microstructure and Thermal Shock Properties of SiC Materials

SiC 재료의 미세조직 및 열충격 특성

  • Received : 2011.04.11
  • Accepted : 2011.06.20
  • Published : 2011.06.30

Abstract

The thermal shock properties of SiC materials were investigated for high temperature applications. In particular, the effect of thermal shock temperature on the flexural strength of SiC materials was evaluated, in conjunction with a detailed analysis of their microstructures. The efficiency of a nondestructive technique using ultrasonic waves was also examined for the characterization of SiC materials suffering from a cyclic thermal shock history. SiC materials were fabricated by a liquid phase sintering process (LPS) associated with hot pressing, using a commercial submicron SiC powder. In the materials, a complex mixture of $Al_2O_3$ and $Y_2O_3$ powders was used as a sintering additive for the densification of the microstructure. Both the microstructure and mechanical properties of the sintered SiC materials were investigated using SEM, XRD, and a three point bending test. The SiC materials had a high density of about 3.12 Mg/m3 and an excellent flexural strength of about 700 MPa, accompanying the creation of a secondary phase in the microstructure. The SiC materials exhibited a rapid propagation of cracks with an increase in the thermal shock temperature. The flexural strength of the SiC materials was greatly decreased at thermal shock temperatures higher than $700^{\circ}C$, due to the creation of microcracks and their propagation. In addition, the SiC materials had a clear tendency for a variation in the attenuation coefficient in ultrasonic waves with an increase in thermal shock cycles.

Keywords

Flexural strength;Liquid phase sintering;Microstructure;SiC;Thermal shock property

References

  1. 윤한기, 정헌채 (2006). "LPS-SiC 세라믹스의 굽힘강도 특성에 미치는 미시조직 영향", 제20권, 제6호, 한국해양공학회지, pp 96-100.
  2. 이상필, 이문희, 이진경 (2008). "$Al_2O_3$$Y_2O_3$ 입자를 함유한 액상소결 SiC 재료의 특성", 제22권, 제4호, 한국해양공학회지, pp 59-63.
  3. Dong, S., Katoh, Y., Kohyama, A. (2003). "Processing Optimization and Mechanical Evaluation of Hot Pressed 2D Tyranno-SA/SiC Composites", Journal of the European Ceramic Society, Vol 23, pp 1223-1231. https://doi.org/10.1016/S0955-2219(02)00298-4
  4. Hasegawa, A., Kohyama, A., Jones, R.H., Snead, L.L. and Fenici, P.(2000). "Critical Issue and Current Status of SiC/SiC Composite for Fusion", Journal of Nuclear Materials. Vol 283-287, pp 128-137. https://doi.org/10.1016/S0022-3115(00)00374-3
  5. Hasselman, D.P.H. and Singh, J.P. (1984). "Role of Mixed-Mode Crack Propagation in Thermally Shocked Bbrittle Materials", Theoretical and Applied Fracture Mechanics, Vol 2, pp 59-65. https://doi.org/10.1016/0167-8442(84)90040-5
  6. Jones, R.H., Hasegawa, L.A., Katoh, Y., Kohyama, A., Riccardi, B., Snead, L.L., and Weber, W.J. (2002). "Promise and Challenges of SiCf/SiC Composite for Fusion Energy Applications", Journal of Nuclear Materials. Vol 307-311, pp 1057-1072. https://doi.org/10.1016/S0022-3115(02)00976-5
  7. Katoh, Y., Snead, L.L., Henager, C.H. Jr., Hasegawa A., Kohyama A., Riccardi, B. and Hegeman H., (2007). "Current Status and Critical Issues for Development of SiC Composites for Fusion Applications", Journal of Nuclear Materials. Vol 367-370, pp 659-671. https://doi.org/10.1016/j.jnucmat.2007.03.032
  8. Kotani, M., Kohyama, A. and Katoh, Y. (2001). "Development of SiC/SiC Composites by PIP in Combination with RS", Journal of Nuclear Materials, Vol 289, pp 37-41. https://doi.org/10.1016/S0022-3115(00)00680-2
  9. Lee, S.P., Park, J.S., Katoh, Y., Kohyama, A., Kim, D.H., Lee, J.K. and Yoon, H.K. (2002). "Process, Microstructure and Flexural Properties of Reaction Sintered Tyranno SA/SiC composites", Journal of Nuclear Materials, Vol 307-311, pp 1191-1195. https://doi.org/10.1016/S0022-3115(02)01059-0
  10. Lee, S.P., Jin, J.O., Park, J.S. and Koyama, A. (2004). "High Temperature Characterization of Reaction Sintered SiC Based Materials", Journal of Nuclear Materials, Vol 329-333, pp 534-538. https://doi.org/10.1016/j.jnucmat.2004.04.283
  11. Lee, S.P., Shin, Y.S., Bae, D.S., Min, B.H., Park, J.S. and Koyama, A. (2006). "Fabrication of Liquid Phase Sintered SiC Materials and Their Characterization", Fusion Engineering and Design, Vol 81, pp 963-967. https://doi.org/10.1016/j.fusengdes.2005.09.025
  12. Lee, J.K., Lee, S.P., Cho, K.S., Lee, J.H. and Kohyama, A. (2009). "Characterization Evaluation of Liquid Phase-Sintered SiC Materials by a Nondestructive Technique", Journal of Nuclear Materials, Vol 386-388, pp 487-490. https://doi.org/10.1016/j.jnucmat.2008.12.140
  13. Lee, J.K., Lee, S.P. and Byun, J.H. (2010). "Charaterization of SiC Based Composite Materials by the Infiltration of Ultra-Fine SiC Particles", Fusion Engineering and Design, Vol 85, pp 1376-1380. https://doi.org/10.1016/j.fusengdes.2010.03.047

Acknowledgement

Supported by : 동의대학교