The Effect of Size and Distribution of Second Phase Particles and Voids on Sintering

Abstract

The equations for the kinetics of diffusion controlled coarsening were solved with no restrictions on the size or spacial distribution of the particles in the system. In the limit of very small volume fractions, approximately parts per million of second phase, the treatment reduces to that of Lifshitz-Wagner. As the volume fraction is increased there is a deviation from the predictions of Lifshitz-Wagner, this deviation can be more than an order of magnitude at moderate volume fractions and it may be either positive or negative. The deviation tends to be positive if particles of greatly different radii are near neighbors, and tends to be negative if particles of only slightly different radii are near neighbors. This treatment of diffusion controlled coarsening can be applied to give a better understanding of how voids coarsen during sintering. The treatment can also be used to better understand the coarsening of second phase particles in the sintering of two phase composites.