Interfacial energy grain boundary

The degree of wetting depends on the relationship between the interfacial and grain-boundary energies according to the relationship... 

Fig. 5.23 Grain boundaries in SrTiOa (mpe = 9-5 10 cm" ) recorded by high-resolution electron microscopy a) atomically shaup, low-energy grain boundary (symmetrical E3 (111), without amorphous interfacial layer), b) triple point with sunorphous intergranular phase (thickness 1 nm) c) faceted grain boundary with amorphous interfaciaJ layer (thickness sa 1 nm). Fracture surface (d) with energetically favourable, step-shaped surfaces. From Refs. [139,140].

Figure C2.11.7. An illustration of tlie equilibrium dihedral angle, 0, fonned by tlie balance of interfacial energies at a pore-grain boundary intersection during solid-state sintering.

The distribution of the liquid is determined by the interfacial energy between the liquid and the solid matrix relatively to the grain boundary energy. An example is shown in Figure 6.11 (a), where an important characteristic of grain boundaries, the... 

In cases where the interfacial energy is dependent on orientation, the equilibrium condition (6.41) does not hold [19]. Some grain boundaries will then represent higher Gibbs energies than others, and if kinetics allow for reorientation, certain grain boundaries will become dominant. However, in most cases the kinetics of... 

The nucleus has cylindrical symmetry around an axis normal to the boundary and mirror symmetry across the grain-boundary plane. Figure 19.27 shows a cross section of the nucleus centered in a patch of boundary of constant circular area, Ac. The area of the nucleus projected on the boundary is indicated by A. The total interfacial energy of this configuration is then... 

Theoretical considerations by Clarke and co-workers (Clarke, 1987 Clarke etal., 1993) show that an equilibrium film thickness arises from the competition between attractive dispersion forces determined by the dielectric properties of the grains and repulsive disjoining forces which can be steric forces and/ or double-layer forces. Wetting will occur when the solid-solid boundary energy, yb, is less than that of the wetted boundary, 2y, where y is the liquid-solid interfacial energy (Clarke, 1985), provided that there is a suitable source of liquid, for example as a consequence of liquid-phase sintering at high temperatures. 

Ni-20Cr 0 0.35 RE addition results in reduction in free S O content, increase in interfacial energy and grain boundary mobility, low cavitation [33]... 

Figure 22. L.h.s. Four basic space charge situations involving ionic conductors (here silver ion conductor) a) contact with an isolator, b) contact with a second ion conductor, c) grain boundary, d) contact with afluid phase. R.h.s. Bending of energy levels and concentration profiles in space charge zones ( = 0 refers to the interfacial edge).

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