A new kinetic description for phase separation of materials

This Letter presents a new kinetic description for phase separation of materials. The unstable non-uniform regions fluctuate to form the steadily critical non-uniform regions, which diffuse to grow by either nucleation growth or Spinodal decomposition mechanism. The equation describing fluctuation stage is c(r,t)-c(0) = Pcos(beta Wt)cos(beta.r), and the equations describing 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). The process of forming a steadily critical non-uniform region is that the region size fluctuates near the critical one, the amplitude of fluctuation decreases gradually, and the composition of region tends to stable. (C) 2000 Published by Elsevier Science B.V. All rights reserved.