SIMULATION OF MIGRATION AND COALESCENCE OF METAL INCLUSIONS IN HOMOGENEOUS AND ISOTROPIC MEDIA

Simulations have been performed on the evolution of the size distribut ion of metal inclusions during the process of migration and coalescenc e in a 3D medium of infinite extent. Diffusion coefficients of the for m D(r) = D(0)r(-alpha) have been used to describe different diffusion mechanisms. Simulations show that any initial size distribution conver ges to a fixed shape after a transient. The size distribution is a fix ed shape in the sense that it is given as a time dependent scaling of a time independent shape function. In addition to simulations we have investigated analytically how quantities like transient duration, the time dependent scaling parameters and the fixed point shape itself dep end on quantities like concentration, diffusion coefficient and diffus ion mechanism. It turns out that the fixed point shape depends on the diffusion mechanism. However, the dependence is only weak, so that it is probably not possible to deduce the diffusion mechanism from the sh ape of a measured size-distribution. (C) 1998 Elsevier Science B.V. Al l rights reserved.