Orientation dependence of the surface free energy

Experiments on the equiUbrium shape of small crystallites and on the groove angle at grain boundaries indicate an orientation dependence of the surface free energy. The value the surface free energy varies by several percent for different surface orientations at high temperature. This anisotropy is e.g. responsible for the faceted shape of the crystallites shown in Fig. 4. 

Fig. 4. Scanning electron microscopy image of the anisotropic faceted morphology of a lead crystallite. This equihhrium shape has been analysed to derive the orientation dependence of the surface free energy at various temperatures, see chapter 4.4.7.3.1 [83Hey],...

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