Sintering has been recognized as a complex evolution of microstructure during thermal treatments. The densification in such process is usually attributed to diffusion parameters, i.e. certain mass transport mechanisms would promote densification and others would not. In this work, a new model demonstrating that the interface energies are determinant factors in the densification is drawn. Considering that the mass transport mechanism of grain growth is the same as that of pore elimination, and supposing some reasonable hypothesis about the geometric evolution during sintering, densification is related to the dihedral angle of the system. Since the dihedral angle is directly proportional to interface energies, the ratio between grain surface and grain boundary energies determines densification. Good agreement of the numerical predictions with the experimental data-was obtained. (C) 2003 Elsevier Science B.V. All rights reserved.