Linear-parabolic transition in reactive diffusion – a concept of kinetic modelling

A flexible concept for the computational description of the phase formation and growth in solid state reactions is described. Unlike in other established approaches, it is not required to predefine and trace phase boundaries by dividing surfaces or similar concepts. We show how to extend this concept to the transition between linear to parabolic growth kinetics. Although no interphase boundaries are predefined, it is nevertheless possible to correctly describe the impact of interfacial transport barriers. This allows a transparent modelling of the linear-parabolic transitions in reactive diffusion. For proving this concept an exact analytical solution of the reactive diffusion problem is presented that can be used with any phase diagram of an arbitrary number and composition of forming intermetallics.