Amorphous phases in materials microstructure

Formation of a "constrained liquid" as the boundary film with a constant th ickness and segregation of the surplus "free liquid" into the joint pockets in the microstructure of the liquid-phase sintered ceramics has been ascri bed to an additional interaction in the system. The parallel tangent constr uction has been derived as condition of true thermodynamic equilibrium betw een the constrained and the free liquid. Similarly constrained equilibrium has been considered for amorphous boundary phase and suggested as possible explanation of its apparent stability.