Conclusions
The results of experiments on the growth of alumina whiskers from Fe-Al alloys in wet hydrogen atmosphere can be summarized as follows:
Whisker growth starts at about 1400 °C. The much faster growinga whiskers form in the temperature range 1400–1550 °C, andc whiskers grow at right angles to thea whiskers above 1500 °C.
Growth rate and morphology depend on the vapor pressure of aluminum over the Fe-Al alloy, on the temperature gradient, and on the concentration of and equilibrium between Al oxides and H2O in the vapor atmosphere.
Alumina whiskers grow on nonreactive substrates (crucible walls), i.e. on materials which do not form compounds with alumina or with aluminum. Epitaxy is not a necessary condition for growth.
The morphology of certainc whisker types shows a close resemblance to naturally occurring barrel-shaped corundum crystals (see cover picture).
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Literatur
Palache, C., Berman, H., Frondel, C.: Dana's System of Mineralogy, Vol. 1 (1946), Vol. 2 (1951). New York: John Wiley
Guebelin, E. J.: Inclusions as a means of gemstone identification. Geological Institute of America, 1953.
Guebelin, E.: Die Edelsteine der Insel Ceylon. Montreux: Corbaz 1968
Carroll-Porcynski, C. Z.: Advanced Materials. New York: Chem. Publishing Co. 1969
Minagawa, S., Gejyo, T.: J. Amer. Ceram. Soc.52, 282 (1969)
Minagawa, S.: J. Amer. Ceram. Soc.55, 77 (1972)
Bootsma, G. A., Gassen, H. J.: J. Crystal Growth10, 223 (1971)
Schmitt, J.: Bull. Soc. Franc. Ceramique73, 3 (1966)
Papkov, V. S., Berezhkova, G. V.: Sov. Phys.-Crystallogr.9, 368 (1964)
Hargreaves, C. M.: J. Appl. Phys.32, 936 (1961)
Drowart, J., et al.: J. Chem. Phys.32, 1366 (1960)
Bonfield, W., Markham, A. J.: J. Mater. Sci.6, 1183 (1971)
Wiedemann, H. G.: Chem. Ing. Techn.36, 1105 (1964)
Dahlke, O., et al.: Z. Metallkunde60, 465 (1969)
Gans, W., et al.: Z. Metallkunde57, 46, (1966)
Minagawa, S., Saito, T., Gejyo, T.: J. Amer. Ceram. Soc.51, 532 (1968)
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Wiedemann, H.G., Sturzenegger, E., Bayer, G. et al. Growth morphology of alumina whiskers. Naturwissenschaften 61, 65–69 (1974). https://doi.org/10.1007/BF00596197
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DOI: https://doi.org/10.1007/BF00596197