Hostname: page-component-cd9895bd7-lnqnp Total loading time: 0 Render date: 2024-12-28T00:08:14.606Z Has data issue: false hasContentIssue false
  • English
  • Français

Synthesis and characterization of sol-gel derived lanthanum hexaluminate powders and films

Published online by Cambridge University Press:  03 March 2011

Michael K. Cinibulk
Michael K. Cinibulk
Affiliation:
Materials Directorate, Wright Laboratory, Wright-Patterson Air Force Base, Ohio 45433
Get access

Abstract

Powders and thin films of high-yield lanthanum hexaluminate (LaAl11O18) were prepared by a sol-gel route and compared with yields obtained by conventional hot-pressing of oxide powders. X-ray diffraction and transmission electron microscopy (TEM) were used to characterize powders and thin films deposited on TEM grids. While the solid-state kinetics of formation of LaA11O18 are known to be extremely sluggish, the yield of LaAl11O18 formed by the sol-gel route was much higher than that obtained by processing under similar conditions by solid-state reaction of elemental oxides. The development of a very fine grained microstructure at 1200 °C and a coarser, much more mature microstructure at 1450 °C, with strong texturing of the magnetoplumbite phase, was observed by TEM. Isolated grains of LaAlO3 were present in all powders and films. Trace impurities, introduced most likely as impurities in the initial alumina sol, appear to have segregated to both the grain boundaries and to the external surfaces of grains in as-prepared films.

Type
Articles
Information
Journal of Materials Research , Volume 10 , Issue 1 , January 1995 , pp. 71 - 76
Copyright
Copyright © Materials Research Society 1995

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

1Geller, S. and Bala, V. B., Acta Crystallogr. 9, 1019 (1956).Google Scholar
2Fritsche, E. T. and Tensmeyer, L. G., J. Am. Ceram. Soc. 50, 167 (1967).CrossRefGoogle Scholar
3Yamaguchi, O., Sugiura, K., Mitsui, A., and Shimizu, K., J. Am. Ceram. Soc. 68, C-44 (1985).Google Scholar
4Roth, R. S. and Hasko, S., J. Am. Ceram. Soc. 41, 146 (1958).CrossRefGoogle Scholar
5Verstegen, J. M. P. J. and Stevels, A. L. N., J. Lumin. 9, 406 (1974).CrossRefGoogle Scholar
6Iyi, N., Inoue, Z., Takehawa, S., and Kimura, S., J. Solid State Chem. 54, 70 (1984).CrossRefGoogle Scholar
7Wang, X. H., Lejus, A-M., and Vivien, D., J. Am. Ceram. Soc. 73, 770 (1990).Google Scholar
8Morgan, P. E. D. and Miles, J. A., J. Am. Ceram. Soc. 69, C-157 (1986).Google Scholar
9Gasperin, M., Saine, M. C., Kahn, A., Laville, F., and Lejus, A. M., J. Solid State Chem. 54, 61 (1984).Google Scholar
10Ropp, R. C. and Carroll, B., J. Am. Ceram. Soc. 63, 416 (1980).CrossRefGoogle Scholar
11Jantzen, C. M. and Morgan, P. E. D., as reported in Card No. 34–467, Joint Committee on Powder Diffraction Standards, International Centre for Diffraction Data, Swarthmore, PA (193).Google Scholar
12Morgan, P. E. D. and Marshall, D. B., Mater. Sci. Eng. A162, 15 (1993).Google Scholar
13Cinibulk, M. K., Ceram. Eng. Sci. Proc. 15, 721 (1994).CrossRefGoogle Scholar
14Cinibulk, M. K., J. Mater. Sci. Lett., in review.Google Scholar
15See, for example, (a) Ultrastructure Processing of Ceramics, Glasses, and Composites, edited by Hench, L. L. and Ulrich, D. R. (John Wiley and Sons, New York, 1984); (b) Better Ceramics Through Chemistry, edited by Brinker, C. J., Clark, D. E., and Ulrich, D. R. (Mater. Res. Soc. Symp. Proc. 32, Elsevier Science Publishing, New York, 1984).Google Scholar
16Hay, R. S., J. Mater. Res. 8, 578 (1993).Google Scholar
17Jagota, S. and Raj, R., J. Cryst. Growth 85, 527 (1987).CrossRefGoogle Scholar