Sintering kinetics at final stage sintering: model calculation and map construction

Ever since the development of a late stage sintering model by Coble in 1961, densification at the final stage of solid state sintering has been explained basically by Coble's model for lattice diffusion. For grain boundary diffusion, equations based on Herring's scaling law were later developed and utilized. The present paper examines previous sintering models, in particular, Coble's sintering model, and presents a new diffusion model and kinetic equations. The new model accounts for the role of grain boundaries and the diffusion area in densification in contrast to Coble's model. Sintering kinetics have been calculated and the relative contributions of lattice and grain boundary diffusion evaluated. It has been shown that the densification mechanism can vary with pore size change during sintering, unlike the conclusions of previous investigations. The results have been highlighted as a sintering diagram. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.