Abstract
The formation of a lamellar porous microstructure in γ-Al2O3 during the dehydration of boehmite (γ-AlOOH) has been studied as a function of the temperature and water vapour pressure conditions under which the dehydration was performed. The γ-Al2O3 samples were characterized by transmission electron microscopy and nitrogen adsorption. A marked dependence of the scale of the microstructure, and of the adsorption characteristics, on water vapour pressure was observed. This pressure dependence of scale and surface area has been discussed in terms of a model, similar to those derived for cellular growth of lamellar microstructures during eutectic and eutectoid reactions, in which the dehydration mechanism is diffusion controlled. The inter-lamellar spacing is determined by the energy available for the formation of a new surface, and an estimate of surface energy for γ-Al2O3 has been made. The partial pressure, \(p_{H_2 O}\), dependence observed has important implications for the possibility of tailoring pore structures.
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Wilson, S.J., McConnell, J.D.C. & Stacey, M.H. Energetics of formation of lamellar porous microstructures in γ-Al2O3 . J Mater Sci 15, 3081–3089 (1980). https://doi.org/10.1007/BF00550379
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DOI: https://doi.org/10.1007/BF00550379