Liquid-phase sintering grain boundary films

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. 

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