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Morphological analyses of minute crystals by using stereo‐photogrammetric scanning electron microscopy and electron back‐scattered diffraction
Author(s) -
KAMEDA JUN,
INOGUCHI RYOICHI,
PRIOR DAVID J.,
KOGURE TOSHIHIRO
Publication year - 2007
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.2007.01854.x
Subject(s) - scanning electron microscope , crystal (programming language) , materials science , optics , electron backscatter diffraction , tilt (camera) , electron diffraction , electron microscope , diffraction , crystallography , electron , geometry , physics , chemistry , mathematics , computer science , programming language , quantum mechanics
Summary We present a new method for the morphological analyses of minute faceted crystals by combining stereo‐photogrammetric analysis of scanning electron microscope images and electron back‐scattered diffraction. Two scanning electron microscope images of the same crystal, recorded at different tilt angles of the specimen stage, are used to determine the orientations of crystal edges in a specimen‐fixed coordinate system. The edge orientations are converted to the indices [ uvw ] in the crystal system using the crystal orientation determined by electron back‐scattered diffraction analysis. The Miller indices of crystal facets are derived from the indices of the edges surrounding the facets. The method is applicable to very small crystal facets. The angular error, as derived from tests using a calcite crystal of known morphology, is a few degrees. To demonstrate the applicability of the method, the morphology of boehmite (γ‐AlOOH) precipitated from solution during the dissolution of anorthite was analyzed. The micrometre‐sized boehmite crystals are surrounded by two {010} basal facets and eight equivalent side facets that can be indexed equally well as {323}, {434} or {545}. We suggest that these side facets are in fact {111}, the morphology having been modified slightly (by a few degrees) by a small extension associated with opening along (010) microcleavage planes. Tiny {140} facets are also commonly observed.