A numerical analysis was made of the sintering-neck growth-rate between rigid spherical particles of the same size. The contributions made by surface, grain-boundary and volume diffusion transport to the sintering kinetics during the first and second stages of sintering were estimated. It was shown that the 3-dimensional problem of matter redistribution during sintering could be reduced to a 2-dimensional problem if the effective diffusion coefficients were introduced. The effective diffusion coefficients were grain-boundary diffusion coefficients that included the contribution of volume diffusion. The effective diffusion coefficients were sensitive to the sintering stage. They had different forms during the first and second stages. During the second stage of sintering, the unified effective diffusion coefficient was determined. It was demonstrated that the effective diffusion coefficients could be used also for the description of pressure-assisted sintering.

Effective Diffusion Coefficients in Solid-State Sintering. A.L.Maximenko, E.A.Olevsky: Acta Materialia, 2004, 52[10], 2953-63