Effect of different sizes of subcritical nuclei on kinetics of transformation in the solid state

Amorphous modifications of the sulfur group elements contain embryos with d ifferent numbers of members of the stable nucleus. During the transformatio n these embryos form stable nuclei at different rates: the larger the numbe r of members. the more rapid is the formation of a stable nucleus. The: nuc leation rate depends on the rate of increase of an individual embryo to the critical size and on the number of embryos. Foul cases of the transformati on are discussed depending on the number of embryos of different sizes. The value of the Avrami exponent for each case was given. Results of the discu ssion were used to explain the transformation kinetics of amorphous modific ations of selenium and sulfur. (C) 2000 Elsevier Science B.V. All rights re served.