Equilibrium distribution of liquid during liquid phase sintering of composition gradient materials

The thermodynamics of aggregates of solid particles immersed in a percolating liquid is revisited. The expressions of the driving forces involve shape factors which are functions of the liquid volume fraction, u, and average particle coordination, nc. A model considering arbitrary, isotropic interface energies, (gamma)sl and (gamma)ss, is proposed for expressing these functions. The paper discusses the bearings of the model for the case of a dihedral angle (psi) = 0. The driving force for the absorption of liquid increases both with decreasing u and with decreasing nc. It is found that nc tends to decrease spontaneously. The model is applied to: (1) the prediction of liquid migration in bi-materials assemblies, (2) the computation of the relationships between spatial distributions of u, nc, and particle size in gradient materials, and (3) the analysis of the distribution of u resulting from liquid migration induced by gravity.