Shape Sensitivity of Initial Sintering Equations

Initial sintering equations are shown to depend as much on possible particle shape variations in powder systems as on the mechanism of material transport. Also, competing mechanisms, such as surface diffusion, may alter the generally assumed relations between neck growth and shrinkage and so may affect the sintering kinetics. When shrinkage occurs by volume diffusion, both effects may be overcome by measuring the size of the interparticle boundary as well as the shrinkage during sintering. When grain boundary diffusion is the mechanism of shrinkage, both the cross-sectional area and the radius of curvature of the neck must be measured during sintering. The usefulness of simultaneous measurements of neck growth and shrinkage is demonstrated with literature data for copper.