Sintering of pseudo-boehmite, acicularγ-Al2O3 produced by dehydration of pseudo-boehmite, andγ-Al2O3 ex alum was investigated. The sintering process was studied by X-ray diffraction, transmission electron microscopy with selected area electron diffraction and BET surface area measurements. The solid state reaction toα-Al2O3 causes a steep drop of the surface area to less than 10 m2g−1. The acicular pseudo-boehmite andγ-Al2O3 supports exhibit an intermediate state where the acicular particles assume a rod-like shape and the surface area falls from about 300 to 100 m2g−1. It was established that reaction to α-Al2O3 and, hence, sintering proceeds via a nucleation and growth mechanism. The rate-limiting step is nucleation of α-Al2O3. Consequently, the contacts between the elementary alumina particles dominate the sinter process. The contact between the acicular elementary particles of pseudoboehmite andγ-Al2O3 studied leads to the reaction to α-Al2O3 to be almost complete after keeping samples for 145 h at 1050 °C. Decomposition of alum produces very small particles showing negligible mutual contacts. Consequently an elevated thermal stability is exhibited. Treatment of the alumina ex alum with water and drying results in a xerogel in which contact between elementary particles is much more intimate. Accordingly, treatment at 1050 °C causes a sharp drop in surface area.
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B. C. Lippens andJ. H. De Boer,Acta Crystallogr. 17 (1964) 1312.
B. C. Lippens, J. J. Steggerda, in “Physical and Chemical Aspects of Adsorbents and Catalysts” (Academic, New York, 1970), p. 171.
S. Soled,J. Catal.,81 (1983) 252.
H. Schaper andL. L. Van Reijen,Thermochimica Acta 77 (1984) 383.
H. Schaper, E. B. M. Doesburg, P. H. M. De Korte andL. L. Van Reuen,Solid State Ionics,16 (1985) 261.
D. S. Tucker,J. Amer Ceram. Soc. 68 (1985) C163.
S. J. Wilson,Mineral. Mag. 43 (1979) 301.
J. F. Berar, D. Grebille, P. Gregoire andD. Weigel,J. Phys. Chem. Solids 45 (1984) 147.
D. S. Maciver, H. H. Tobin andR. T. Barth,J. Catal. 2 (1963) 485.
S. J. Wilson, J. D. C. McConnell andM. H. Stacey,J. Mater Sci. 15 (1980) 3081.
K. J. Morrissey, K. K. Czanderna, C. B. Carter andR. P. Merrill,Comm. Amer. Ceram. Soc., May (1984) C88.
M. Kumagai andG. L. Messing,J. Amer. Ceram. Soc. 68 (1985) 500.
V. A. Dzis'ko, T. S. Vinnikova, L. M. Kefeli andI. A. Ryzhak,Kin. Kat. 7 (1966) 859.
R. S. Alwitt, in ‘Oxides and Oxide Films”, Vol. IV, 1976, (Marcel Dekker, New York, 1976) p. 169.
F. W. Dynys andJ. W. Halloran,J. Amer. Soc.,65 (1982) 442.
D. W. Johnson andP. K. Gallagher,ibid. 54 (1971) 461.
P. Burtin, J. P. Brunelle, M. Pijolat andM. Soustelle,Appl. Catal. 34 (1987) 225.
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Tijburg, I.I.M., De Bruin, H., Elberse, P.A. et al. Sintering of pseudo-boehmite and γ-Al2O3 . J Mater Sci 26, 5945–5949 (1991). https://doi.org/10.1007/BF01130139
- Transmission Electron Microscopy
- Thermal Stability
- Electron Diffraction
- Solid State Reaction