SYMPATHETIC NUCLEATION - AN OVERVIEW

Sympathetic nucleation is defined as the nucleation of a precipitate c rystal at an interphase boundary of a crystal of the same phase when t hese crystals differ in composition from their matrix phase throughout the transformation process. Following a brief history of the discover y and interpretation of this phenomenon, the means of identifying the presence of sympathetic nucleation are described. The morphological co nfigurations most frequently produced by sympathetic nucleation are il lustrated. Heterogeneous nucleation theory is then applied to explain sympathetic nucleation. Particular emphasis is placed upon the driving force for sympathetic nucleation, since many of the effects of phase diagram geometry and supersaturation upon sympathetic nucleation can b e simply explained upon this basis.