Hostname: page-component-7479d7b7d-767nl Total loading time: 0 Render date: 2024-07-13T16:27:10.089Z Has data issue: false hasContentIssue false
  • English
  • Français

Microstructural evolution in sintering of ALOOH gels

Published online by Cambridge University Press:  31 January 2011

Walter A. Yarbrough  and
Rustum Roy
Walter A. Yarbrough
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802
Rustum Roy
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802
Get access

Abstract

Materials derived by precipitation or polymerization chemistry (e.g., “sol-gel” methods) are usually obtained in noncrystalline or otherwise metastable phases, and transformation to more thermodynamically stable phases generally occurs by a nucleation and growth process. In a fully reconstructive transformation, such as occurs in the alumina system, the activation energy for nucleation may be higher than that for simple short-range diffusion. Hence nucleation frequency can be a controlling factor in the development of microstructurc. The efficacy of seeding as a method of microstructural and phase control in solution-derived or so-called sol-gel materials has been clearly demonstrated for the alumina system. The epitaxial nature of this phenomenon is explored, using the polarizing microscope to follow the crystallographic orientation of the transformed material as the transformation proceeds, showing that this is epitaxial in nature, and that the nucleation frequency in unseeded material is relatively low (∼ 1010 cm−3). The microscope was then used to demonstrate the effect on nucleation frequency of seeding with materials selected to be isostructural, isotypic, and having little or no similarity to the corundum structure. Using these and other methods, the seeding phenomenon in alumina gels is shown to result from epitaxial growth of the stable corundum phase on isostructural or isotypic nuclei in the solid state. This approach is applied to formulate hypotheses for the mechanisms by which some of the previously reported effects of seeding, e.g., enhanced densification and microstructural refinement, can be understood and to formulate a set of generalizations for its potential application to other systems.

Type
Articles
Information
Journal of Materials Research , Volume 2 , Issue 4 , August 1987 , pp. 494 - 515
Copyright
Copyright © Materials Research Society 1987

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Roy, R., in the Program of the 1982 Annual Materials Research Society Meeting, Boston, MA, November 1982, Abstract Nl.l.Google Scholar
2Yarbrough, W. A. and Roy, R. in the Program of the 87th Annual American Ceramic Society Meeting, Cincinnati, OH, May 1985, Poster No. 28-GBP-85.Google Scholar
3Yarbrough, W. A. and Roy, R., in the Program of the 1985 Annual Materials Research Society Meeting, Boston, MA, December 1985, Poster L5.9.Google Scholar
4Ervin, G. and Osborn, E. F., J. Geol. 59, 331 (1951).Google Scholar
5Hill, V. G., Roy, R., and Osborn, E. F., J. Am. Ceram. Soc. 35 (6), 135 (1952).CrossRefGoogle Scholar
6Roy, R., Roy, D. M., and Osborn, E. F., J. Am. Ceram. Soc. 33, 152 (1950).CrossRefGoogle Scholar
7Suwa, Y., Komarneni, S., and Roy, R., J. Mater. Sci. Lett. 5, 21 (1986).CrossRefGoogle Scholar
8Suwa, Y., Komarneni, S., and Roy, R., J. Am. Ceram. Soc. 68(9), C238 (1985).CrossRefGoogle Scholar
9Dynys, F. W. and Halloran, J. W., J. Am. Ceram. Soc. 65(9), 442 (1982).CrossRefGoogle Scholar
10Bye, G. C. and Simpkin, G. T., J. Am. Ceram. Soc. 57 (8), 367 (1974).CrossRefGoogle Scholar
11Clark, D. E. and Lannutti, J. J., in the Proceedings of the International Conference on Ultrastructure Processing of Ceramics, Glasses and Composites, edited by Hench, L. L. and Ulrich, Dr. R. (Wiley, New York, 1984), Chap. 10, pp. 127–141.Google Scholar
12Becher, P. F., Sommers, J. H., Bender, B. A., and MacFarlane, B. A., Processing Crystalline Ceramics, edited by Palmour, H., Davis, R. F., and Hare, T. M. (Plenum, New York, 1978), pp. 79–86.CrossRefGoogle Scholar
13Badkar, P. A., Bailey, J. E., and Barker, H. A., Trans. J, Br. Ceram. Soc. 71, 193 (1972).Google Scholar
14Dynys, F. W., Ljungberg, M., and Halloran, J. W., Mater. Res. Soc. Symp. Proc. 32, 321 (1984).CrossRefGoogle Scholar
15Wilson, S. J. and Stacey, M. H., J. Colloid Interface Sci. 82 (2), 507 (1981).CrossRefGoogle Scholar
16Roy, R., J. Am. Ceram. Soc. 39 (4), 145 (1956).CrossRefGoogle Scholar
17Roy, D. M., Am. Mineral. 39, 140 (1954).Google Scholar
18Carniglia, S. C., J. Am. Ceram. Soc. 66 (7), 495 (1983).CrossRefGoogle Scholar
19Deflandre, M., Bull. Soc. Fr. Mineral. 55, 140 (1932).Google Scholar
20Ervin, G., Acta Crystallogr. 5, 103 (1952).CrossRefGoogle Scholar
21Yoldas, B. E., Ceram. Bull. 54 (3), 289 (1975).Google Scholar
22Yarbrough, W. A. and Roy, R., Nature 322, 347 (1986).CrossRefGoogle Scholar
23Dynys, F. W. and Halloran, J. W., in Ref. 11, pp. 142–151.Google Scholar
24Sacks, M. D., Tseng, T. Y., and Lee, S. Y., Ceram. Bull. 63 (2), 301 (1983).Google Scholar
25Tucker, D. S., J. Am. Ceram. Soc. 68 (7), C163 (1985).CrossRefGoogle Scholar
26Kachi, S., Momiyama, K., and Shimizu, S., J. Phys. Soc. Jpn. 18 (1), 106 (1963).CrossRefGoogle Scholar
27Roy, R. and Osborn, E. F., Problems of Clay and Laterite Genesis, Symposium Proceedings (A.I.M.E., New York, 1952), pp. 76–80.Google Scholar
28Ervin, G., PhD thesis, The Pennsylvania State University, 1949.Google Scholar
29Kumagi, M. and Messing, G. L., J. Am. Ceram. Soc. 67 (11), C230 (1984).Google Scholar
30Kumagi, M. and Messing, G. L., J. Am. Ceram. Soc. 68(9), 500 (1985).CrossRefGoogle Scholar
31Rhodes, W. H., J. Am. Ceram. Soc. 64(1), 19 (1981).CrossRefGoogle Scholar
32Lee, J. B., Corrosion 37(8), 467 (1981).CrossRefGoogle Scholar
33Eckert, L. J., M. S. thesis, The Pennsylvania State University, 1972.Google Scholar
34Bykhovski, A. I., Solid State Transformations, edited by Sirota, N. N., Gorskii, F. K., and Varikash, V. M. (Institute of Solid State Physics and Semiconductors, Academy of Sciences of the Byelorussion SSR, Minsk); Translation by Consultants Bureau, New York, 1966.Google Scholar
35Her, R. K., J. Am. Ceram. Soc. 47(7), 339 (1964).Google Scholar
36Laying, E. T., U. S. Patent No. 2,487,564 (8 November 1949).Google Scholar
37Bailey, W. A. and Bittner, C. W., U. S. Patent No. 2,398,610 (16 April 1946).Google Scholar