A new kinetic description for phase separation of materials

This Letter presents a new kinetic description for phase separation of mate rials. The unstable non-uniform regions fluctuate to form the steadily crit ical non-uniform regions, which diffuse to grow by either nucleation growth or Spinodal decomposition mechanism. The equation describing fluctuation s tage is c(r,t)-c(0) = Pcos(beta Wt)cos(beta.r), and the equations describin g diffusion stage are lambda(2) = Ht (nucleation growth) and c(r,t)- c(0) = PQ(2)exp[R-2(beta)t]cos(beta.r) (early stage of Spinodal decomposition). T he process of forming a steadily critical non-uniform region is that the re gion size fluctuates near the critical one, the amplitude of fluctuation de creases gradually, and the composition of region tends to stable. (C) 2000 Published by Elsevier Science B.V. All rights reserved.