Dihedral angles in silicon carbide

The commonly accepted hypothesis says that the role of sintering activators such as carbon and boron consists in modifying the relation between the energy of surface and that of grain boundaries in SiC. This means that dihedral angles in samples containing one of the activators, both of them or none should be different. To verify this hypothesis we measured dihedral angles in all the mentioned cases. The observed values of dihedral angles were always much bigger than the limiting one of 60°. Moreover, they did not differ significantly and, according to the statistical analysis could be treated as constant. As a consequence our results contradict the opinion saying that the activators modify the energy of surface and grain boundaries.