Abstract
The study of the microstructure of materials by imaging sections of properly prepared samples is a well-established characterisation technique. For this, two-dimensional (2D) cuts are prepared for light optical reflecting metallography (LOM) or scanning electron microscopy (SEM). LOM is very sensitive to topographic irregularities owing to the small depth of field in the range < 0.3 µm. The achievable lateral resolution is > 0.2 µm, if there is sufficient reflecting contrast. Etching is a well-known methodology to create topographical differences between phases or of phase boundaries. The contrast depends on the phases’ reflectivity, which can be modified by the wavelength of the illuminating light and by surface treatments (interference coating) of surfaces neatly polished either mechanically or by ion bombardment.
