Abstract
Two kinds of monophasic gels were synthesized from silicon ethyl ester (TEOS) and aluminium nitrate mixture by varying the water-alcohol content of the system. The mullitization reaction paths of the two gels were studied by differential thermal analysis (DTA) and X-ray diffraction techniques. The first kind of monophasic gel exhibited cubic mullite (Si-Al spinel) on the 980 °C exotherm and a further two more broad exotherms at 1150 and 1243 °C. This phenomenon resembles the DTA thermogram of a kaolinitic clay. The later two exotherms have been explained as due to the formation of mullite by two different reaction paths from the two phases appearing in the 980 °C exotherm. Nucleation and crystallization of mullite from amorphous alumino silicate phase takes place at ∼ 1150 °C, and transformation of cubic mullite to orthorhombic mullite takes place at ∼ 1245 °C. The second kind of monophasic gel exhibited only one exotherm and produced exclusively tetragonal mullite at ∼ 980 °C. The results suggest that pure mullite formation is possible when water induced hydrolysis of TEOS is avoided during the gelation process.
Similar content being viewed by others
References
K. Okaka, N. Otsuka and S. Somiya, J. Am. Ceram. Soc. 70 (1991) 1633.
A. Aksay, D. M. Dabbs and M. Sarikaya, ibid. 74 (1991) 2343.
M. D. Sacks, H. W. Lee and J. A. Pask, in “Ceramic Tranactions”, Vol. 6, “Mullite and Mullite Matrix Composites”, edited by S. Somiya, R. E. Davis and J. A. Pask (1990) p. 167.
A. K. Chakraborty, J. Am. Ceram. Soc. 62 (1979) 120.
H. Suzuki, H. Saito, Y. Tomokiyo and Y. Suyame, in “Ceramic Transactions”, Vol. 6, edited by S. Somiya, R. E. Davis and J. A. Pask (1990) p. 263.
H. Schneider and T. R. Lipinski, J. Am. Ceram. Soc. 71 (1988) C-162.
D. X. Li and W. J. Thomson, J. Mater. Res. 6 (1991) 819.
A. K. Chakravorty and D. K. Ghosh, J. Am. Ceram. Soc. 71 (1988) 978.
B. E. Yoldas and D. P. Partlow, J. Mater. Sci. 23 (1988) 1895.
K. Okada and N. Otsuka, ibid. 5 (1986) 1315.
Y. Hirata, K. Sakeda, Y. Matsushita and K. Shevnada, Yogo-Kyokai-Shi, 93 (1985) 101.
K. Hamano, Z. Nakagawa, G. Gun-Ji and T. Sato, in “Mullite”, edited by S. Somiya, (Uchida Rokakoho, Tokyo, Japan, 1985) pp. 37–49.
L. A. Paulick, Y. F. Yu and T. I. Mah, in “Ceramic Powder Science, Advances in Ceramics”, Vol. 21, edited by G. L. Messing, K. S. Mazdiyasni, J. W. McCauley and R. A. Haber (American Ceramic Society, Westerville, OH, 1987) pp. 121–9.
Chi. S. Hsi, H. Y. Lu and F. S. Yen, J. Am. Ceram. Soc. 72 (1989) 2208.
A. K. Chakravorty, unpublished work (1985).
D. X. Li and W. J. Thomson, J. Am. Ceram. Soc. 74 (1991) 574.
K. Okada and N. Otsuka, in “Ceramic Transactions”, Vol. 6, edited by S. Somiya, R. E. Davis and J. A. Pask (1990) p. 425.
D. W. Hoffman, R. Roy and S. Kernarneni, J. Am. Ceram Soc. 67 (1984) 468.
A. K. Chakravorty, J. Mater. Sci. (1994) in press.
J. A. Pask, X. W. Zhang, A. P. Tomsia and B. E. Yoldas, J. Am. Ceram. Soc. 70 (1987) 700.
S. Kanzaki, H. Tabata, T. Kumazawa and S. Ohta, ibid. 68 (1985) C-6.
J. C. Huling and G. L. Messing, ibid. 74 (1991) 2374.
A. K. Chakravorty and D. K. Ghosh, ibid. 74 (1991) 1401.
A. K. Chakravorty, ibid. 75 (1992) 2043.
K. Srikrishna, G. Thomas, R. Martinez, M. P. Corral, S. De Aza and J. S. Moya, J. Mater. Sci. 25 (1990) 607.
K. Okada and N. Otsuka, J. Am. Ceram. Soc. 69 (1986) 652.
B. Sonuparlok, M. Sarikaya and I. A. Aksay, ibid. 70 (1987) 837.
I. M. Low and R. Mcpherson, J. Mater. Sci. 24 (1989) 926.
K. Okada and N. Otsuka, J. Am. Ceram. Soc. 70 (1987) C-245.
C. J. Brinker, K. D. Keefer, D. W. Schaefer and C. S. Ashby, J. Non-Cryst. Solids 48 (1982) 47.
J. Zarzyeki, M. Prassas and J. Phalippou, J. Mater. Sci. 17 (1982) 3371.
S. P. Mukherjee, J. Non-Cryst. Solids 42 (1980) 477.
K. C. Chen, T. Tsuchiya and J. D. Mackenzie, ibid. 81 (1986) 227.
B. E. Yoldas, ibid. 83 (1986) 375.
H. Schmidt, H. Scholz and A. Kaiser, ibid. 63 (1984) 1.
R. K. Iller, “The Colloid Chemistry of Silica and Silicates” (Cornell University Press, New York, 1955) p. 68.
R. Aelion, A. Loebel and F. Erich, J. Am. Chem. Soc. 72 (1950) 5706.
M. F. Bechtold, R. D. Vest and L. P. Plambeck Jr, ibid. 90 (1968) 4590.
Yu. Paoting, Liu, Hsiaoming and W. Yuguang, J. Non-Cryst. Solids 52 (1982) 511.
R. K. Iller, “The Colloid Chemistry of Silica and Silicates” (Cornell University Press, New York, 1955) pp. 40–45.
B. E. Yoldas, J. Am. Ceram. Soc. 66 (1982) 387.
S. Saka and K. Kamiya, J. Non-Cryst. Solids 42 (1980) 403.
A. J. Leonard, P. Ratnasamy, E. D. De. Clerck and J. J. Fripiat, Disc. Farad. Soc. 52 (1971) 98.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Chakraborty, A.K. Role of hydrolysis water-alcohol mixture on mullitization of Al2O3-SiO2 monophasic gels. JOURNAL OF MATERIALS SCIENCE 29, 6131–6138 (1994). https://doi.org/10.1007/BF00354552
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF00354552