Theory of the Dependence of Densification on Grain Growth During Intermediate-Stage Sintering

A semiempirical model for intermediate‐stage sintering is developed based on simultaneously occurring volume and grain‐boundary diffusion mechanisms of mass transport and explicitly incorporating the effects of grain growth. The sintering equation derived depends strongly on the reduction of pore number density associated with grain growth and is independent of the mechanism of grain growth. The time and temperature dependencies of densification predicted by the equation, which are tested using data for metal and ceramic powders, agree well with observations. The data indicate that grain‐boundary diffusion contributes negligibly to densification.