Abstract
A method is described by means of which the mean inner potential of glassy grain-boundary or interfacial films of 0·5–1·5 nm in thickness can be measured using transmission electron microscopy. The approach is based on the quantitative assessment of the intensity distribution associated with Fresnel diffraction at the boundary. The measurement of specimen thickness is shown to be the limiting factor in determining the accuracy of the method. Given the simultaneous qualitative application of electron energy-loss spectroscopy, to which the method is ideally complementary in a quantitative sense, the chemistry of a boundary can potentially be derived. The method's usefulness is demonstrated by its application to the characterization of a range of amorphous grain-boundary films in various engineering ceramics.
