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Dehydration Sequence of Gibbsite by Electron‐Beam Irradiation in a TEM
Author(s) -
Kogure Toshihiro
Publication year - 1999
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1999.tb01822.x
Subject(s) - gibbsite , dehydration , irradiation , sequence (biology) , electron , materials science , electron beam processing , cathode ray , mineralogy , radiochemistry , chemistry , crystallography , nuclear physics , aluminium , metallurgy , physics , biochemistry
To understand the dehydration mechanisms of aluminum hydrates, the dehydration sequence of gibbsite (γ‐Al(OH) 3 ) by electron‐beam irradiation has been investigated using transmission electron microscope (TEM). The electron diffraction pattern indicates the formation of chi‐alumina in the initial dehydration stage. The intensity distribution in the diffraction pattern of chi‐alumina is explained by the random close‐packed structure of oxygen/hydroxyl containing gibbsite layer structure. Further irradiation transforms χ‐alumina to η‐ or γ‐alumina and to a phase having a more ordered structure. The dehydrated product at this stage consists of crystallites and voids several nanometers in diameter.