Interfacial two-dimensional phase transitions and impurity segregation

摘要: Abstract Impurity segregation to surfaces and grain boundaries are investigated within a phenomenological theory. Next neighbour interactions between segregating species taken into account in regular solution model. Resulting phase transitions because of interfacial miscibility gaps discussed for equilibrium as well the kinetics ternary systems with repulsive interaction both segregants. The rate determining step remains volume diffusion these cases. In contrast structural may delay significantly nucleation second requires at least locally an oversaturation up critical value compared pure thermodynamically determined coverage first structure. Computer simulations based on model which characterizes structures by different saturation values energies were carried out. A comparison surface measurements Pb Ag Sn Fe shows good agreement.