Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
권호 표지

Micro-Porous Ceramics Using directionally $MgAl_2O_4/MgO$ eutectic crystals

  • Lee, Jong-Ho (Gwangju Research Center, Korea Institute of Industrial Technology)
  • Published : 2005.12.31
Download PDF
⟨ Previous Next ⟩

Abstract

Novel process was tried to obtain micro-porous ceramic body containing continuous pore channel. $MgAl_2O_4/MgO$ eutectic fibers and rods have been grown successfully by the micro-pulling-down method, and the microstructures and optical characterizations of grown crystals were performed. $MgAl_2O_4/MgO$ eutectic fibers of $0.3{\sim}1mm$ in diameter and about 500 mm in length, and the rods having 5 mm in diameter with approximately 60 mm in length have been grown with the $6{\sim}120mm/hr$ of growth speed. The eutectic fibers showed homogeneous microstructure in which MgO fiber aligned to the growth direction in the $MgAl_2O_4$ (spinel) matrix. The grown crystals looked semitransparency under naked eyes. Optical and orientational characterizations were performed. The second phase of MgO (periclase) was easily removed by selective etching with hydrochloric acid, and then porous bodies were obtained.

Keywords

References

  1. F. Schmid and D. Viechnicki, 'Oriented eutectic microstructures in the system $Al_2O_3/ZrO_2$', J. Mater. Sci. 5 (1970) 470 https://doi.org/10.1007/BF00556032
  2. G.R. Fischer, L.J. Manfredo, R.N. McNally and R.C. Doman, 'The eutectic and liquidus in the $Al_2O_3/ZrO_2$ system', J. Mater. Sci. 16 (1981) 3447 https://doi.org/10.1007/BF00586307
  3. Y. Waku, N. Nakagawa, T. Wakamoto, H. Ohtsubo, K. Shimizu and Y. Kohtoku, 'A ductile ceramic eutectic composite with high strength at 1,873 K', Nature 389 (1997) 49 https://doi.org/10.1038/37937
  4. Y. Waku, N. Nakagawa, H. Ohtsubo, K. Shimiz and Y. Kohtoku, 'High-temperature strength and stability of a unidirectionally solidified $Al_2O_3$/YAG eutectic composite', J. Mater. Sci. 33 (1998) 1217
  5. A. Yoshikawa, B. M. Epelbaum, T. Fukuda, K. Suzuki and Y. Waku, 'Growth of $Al_2O_3/Y_3Al_5O_{12}$ eutectic fiber by micro-pulling-down method and its high-temperature strength and thermal stability', Jpn. J. Appl. Phys. 38 (1999) L55
  6. T. Ando and Y. Shiohara, 'Metastable alumina structures in melt-extracted alumina-25 wt% zirconia and alumina-42 wt% zirconia ceramics', J. Am. Ceram. Soc. 74 (1991) 410 https://doi.org/10.1111/j.1151-2916.1991.tb06896.x
  7. J.H. Lee, A. Yoshikawa, S.D. Durbin, D.H. Yoon, T. Fukuda and Y. Waku, 'Microstructure of $Al_2O_3/ZrO_2$ eutectic fibers grown by the micro-pulling-down method', J. Crystal Growth 222 (2001) 791
  8. J.H. Lee, A. Yoshikawa, H. Kaiden, T. Fukuda, D.H. Yoon and Y. Waku, 'Microstructure of $Y_2O_3$ doped $Al_2O_3/ZrO_2$ eutectic fibers by the micro-pulling-down method', J. Crystal Growth 231 (2001) 179
  9. A. Sayir and S.C. Farmer, 'The effect of the microstructure on mechanical properties of directionally solidified $Al_2O_3/ZrO_2(Y_2O_3)$ eutectic', Acta Mater. 48 (2000) 4691 https://doi.org/10.1016/S1359-6454(00)00259-7
  10. J.H. Lee, A. Yoshikawa, T. Fukuda and Y. Waku, 'Growth of $Al_2O_3/YAG/ZrO_2$ ternary eutectic fibers and microstructure', J. Crystal Growth 231 (2001) 115 https://doi.org/10.1016/S0022-0248(01)01375-6
  11. F.L. Kennard, R.C. Bradt and V.S. Stubican, 'Eutectic solidification of $MgO-MgAl_2O_4$' J. Am. Ceram. Soc. 56 (1973) 566
  12. F.L. Kennard, R.C. Bradt and V.S. Stubican, 'Mechanical properties of the directionally solidified $MgO-MgAl_2O_4$ eutectic', J. Am. Ceram. Soc. 59 (1976) 160
  13. F.L. Kennard, R.C. Bradt and V.S. Stubican, 'Directional solidification of the $ZrO_2-MgO$ eutectic', J. Am. Ceram. Soc. 57 (1974) 428 https://doi.org/10.1111/j.1151-2916.1974.tb11374.x
  14. A.M. Alper, R.N. Mcnally, P.H. Ribbe and R.C. Doman, 'The system $MgO-MgAl_2O_4$', J. Am. Ceram. Soc. 45 (1968) 263
  15. D.W. Roy and J.L. Haster, Ceram. Eng. Sci. Proc. 4 (1983) 502
  16. W.J. Minford, R.C. Bradt and V.S. Stubican, 'Crystallography and Microstructure of directionally solidified oxide eutectics', J. Am. Ceram. Soc. 62 (1979) 154 https://doi.org/10.1111/j.1151-2916.1979.tb19043.x