Abstract
Mullite powder with the stoichiometric composition (3Al2O3.2SiO2) was synthesized by a sol-gel process, followed by hypercritical drying with CO2. Within the limits of detection by X-ray diffraction, the powder was amorphous. Crystallization of the powder commenced at ≈1200 °C and was completed after 1 h at 1350 °C. In situ X-ray analysis showed no intermediate crystalline phases prior to the onset of mullite crystallization and the pattern of the fully crystallized powder was almost identical to that of stoichiometric mullite. The synthesized powder was compacted and sintered to nearly theoretical density below ≈1250 °C. The microstructure of the sintered sample consisted of nearly equiaxial grains with an average size of ≈0.2 μm. The effect of heating rate (1–15 °C min−1) on the sintering of the compacted powder was investigated. The sintering rate increased with increasing heating rate, and the maximum in the sintering curve shifted to higher temperatures. The sintering kinetics below ≈1150 °C can be described by available models for viscous sintering.
Similar content being viewed by others
References
L. C. De Jonghe, M. N. Rahaman and C. H. Hsueh, Acta Metall. 34 (1986) 1467.
M. N. Rahaman and L. C. De Jonghe, J. Amer. Ceram. Soc. 70 (1987) C-348.
R. K. Bordia and R. Raj, ibid. 71 (1988) 302.
W. H. Tuan, E. Gilbart and R. J. Brook, J. Mater. Sci. 24 (1989) 1062.
M. N. Rahaman and D.-Y. Jeng, J. Mater. Sci., submitted.
D.-Y. Jeng and M. N. Rahaman, J. Amer. Ceram. Soc., in press.
K. S. Masdiyasni and L. M. Brown, ibid. 55 (1972) 548.
B. L. Metcalf and J. H. Sant, Trans. J. Brit. Ceram. Soc. 74 (1975) 193.
H. Yamada and S. Kimura, J. Ceram. Soc. Jpn 70 (1972) 63.
B. B. Ghate, D. P. H. Hasselman and R. M. Spriggs, Amer. Ceram. Soc. Bull. 52 (1973) 670.
S. Kanzaki, H. Tabata, T. Kumazawa and S. Ohta, J. Amer. Ceram. Soc. 68 (1985) C-6.
B. E. Yoldas, J. Mater. Sci. 12 (1977) 1203.
M. N. Rahaman, L. C. De Jonghe, S. L. Shinde and P. H. Tewari, J. Amer. Ceram. Soc. 71 (1988) C-338.
S. Komarneni, Y. Suwa and R. Roy, ibid. 69 (1986) C-155.
C. J. Brinker and G. W. Scherer, J. Non-Cryst. Solids 70 (1985) 301.
J. Zarzycki, M. Prassas and J. Phalippou, J. Mater. Sci. 17 (1982) 3371.
G. W. Scherer, J. Non-cryst. Solids 87 (1986) 199.
S. S. Kistler, J. Phys. Chem. 36 (1932) 52.
G. A. Nicholson and S. J. Teichner, Bull. Soc. Chim. Fr. 58 (1968) 1906.
S. P. Mukherjee and J. C. Debsikdar, Amer. Ceram. Soc. Bull. 62 (1983) 413.
P. H. Tewari, A. J. Hunt and K. D. Lofftus, Mater. Lett. 3 (1985) 363.
G. W. Scherer, J. Amer. Ceram. Soc. 60 (1977) 236.
I. A. Aksay and J. A. Pask, ibid. 58 (1975) 507.
J. A. Pask, Ceram. Int. 9 (1983) 107.
J. K. Mackenzie and R. Shuttleworth, Proc. Phys. Soc. Lond. 62 (1949) 838.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Jeng, D.Y., Rahaman, M.N. Sintering and crystallization of mullite powder prepared by sol-gel processing. JOURNAL OF MATERIALS SCIENCE 28, 4904–4909 (1993). https://doi.org/10.1007/BF00361154
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF00361154