Hostname: page-component-7bb8b95d7b-w7rtg Total loading time: 0 Render date: 2024-09-11T12:03:32.482Z Has data issue: false hasContentIssue false
  • English
  • Français

Phase Transformations in Sol-Gel Yag Films

Published online by Cambridge University Press:  25 February 2011

R. S. Hay
R. S. Hay*
Affiliation:
Wright Laboratory, Materials Directorate WPAFB OH 45433
Get access

Abstract

Diphasic yttrium-aluminum garnet (YAG) sols were gelled across TEM grids to make films. The films were heat-treated up to 300 hours between 800°C to 1150°C. Microstructure and phase evolution were observed by TEM. YAG fraction and grain size, matrix phases and grain size, nuclei/area, and film thickness were measured. Yttrium-aluminum monoclinic and transition alumina appeared at 800°C. YAG nucleated between 800°C and 950°C. Above 850°C nudeation was site-saturated. Final nuclei density averaged 0.3/μm3. Between 850°C and 1000°C YAG growth had ∼t1/2 dependence and Q ∼ 280 kJ/mole. Below 850°C nudeation was continuous and growth had ∼t0.85 dependence. Above 1000°C YAG growth had ∼t1/4 dependence and the matrix grains coarsened with ∼t1/4 dependence. Unreacted areas were more abundant in thinner films because the nuclei/area and reaction rate decreased. YAG growth was often accompanied by formation of 20 – 100 nm subgrains. Above 1100°C there was some readion to YAG by a different process.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 271: Symposium N – Better Ceramics Through Chemistry V , 1992 , 421
Copyright
Copyright © Materials Research Society 1992

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

1 Hay, R. S. and Hermes, E. E., Ceram. Eng. Sci. Proc. 11, 1526 (1990).CrossRefGoogle Scholar
2 Hay, R. S., Ceram. Eng. Sci. Proc. 12, 1064 (1991).Google Scholar
3 Yoldas, B. E., Am. Ceram. Soc. Bull., 54, 286 (1975).Google Scholar
4 Yoldas, B. E., Am. Ceram. Soc. Bull., 54, 289 (1975).Google Scholar
5 Hay, R. S., Hermes, E. E., and Jepsen, K. A., Ceramic Transactions - Ceramic Thin and Thick Films, ed. by Hiremath, B. V., Am. Ceram. Soc., 11, 243 (1990).Google Scholar
6 Dynys, F. W. and Halloran, J. W., J. Am. Ceram. Soc. 65, 442 (1982).CrossRefGoogle Scholar
7 Pach, L., Roy, R., and Komareni, S., J. Mater. Res. 5, 278 (1990).Google Scholar
8 Roy, R., Suwa, Y., Komareni, S., Science of Ceramic Chemical Processing, Hench, L. L. and Ulrich, D. R, eds., John Wiley and Sons, p. 247 (1986).Google Scholar
9 Hay, R. S., to be published.Google Scholar
10 Keith, H. D. and Padden, F. J., J. Appl. Phys., 34, [8] 2409 (1963).Google Scholar
11 Spry, A., Metamorphic Textures, Pergamon Press (1969).Google Scholar
12 Srlovitz, D. J. and Safran, S. A., J. Appl. Phys., 60, 247 (1986).Google Scholar
13 Zhou, R -S. and Snyder, R. L., Acta Cryst. B47, 617 (1991).Google Scholar
14 Warshaw, I. and Roy, R., J. Am. Cer. Soc., 42, 434 (1959).Google Scholar
15 Keith, M. L. and Roy, R., Am. Min. 39, [1&2] 1 (1954).Google Scholar
16 Vamaguchi, O., Takeoka, K., Hirota, K., Takano, H., Hayashida, A, J. Mat. Sci. 27, [5] 11261 (1992).Google Scholar
17 Pande, C. S., Acta metall. 35, [11] 2671 (1987).Google Scholar
18 Ardell, A. J., Acta metall. 20, 601 (1972).CrossRefGoogle Scholar
19 Wynblatt, P. and Giostein, N. A., Acta metan. 24, 1165 (1976).CrossRefGoogle Scholar
20 DeHoff, R. T., Acta metall. mater. 39, [10] 2349 (1991).Google Scholar
21 Christian, J. W., The Theory of Transformations in Metals and Alloys, 2nd Ed., Pergamon Press, Oxford (1975).Google Scholar
22 Schmalzried, H., Solid State Reactions, 2nd Ed., Verlag Chemie (1981).Google Scholar
23 Keith, H. D. and Padden, F. J., J. Appl. Phys., 35, [4] 1286 (1964).Google Scholar
24 Huling, J. C. and Messing, G. L., J. Am. Ceram. Soc., 74, [10] 2374 (1991).CrossRefGoogle Scholar
25 Wei, W. and Halloran, J. W., J. Am. Ceram. Soc, 71, [7] 581 (1988).Google Scholar
26 Li, D. X. and Thomson, W. J., J. Mater. Res., 5, [9] 1963 (1990).CrossRefGoogle Scholar