Simulation of diffusion-controlled layer growth using the FFD method

The forward finite difference (FFD) method was applied to model diffusion-controlled layer growth in finite multiphase binary diffusion couples. In such samples, the solution of diffusion equations is discontinuous at the phase boundaries, which are in motion during the diffusion process. The model was used to visualize layer growth, the evolution of concentration profiles in diffusion couples and the successive disappearance of individual phases. The features of the procedure are illustrated on the diffusion of nitrogen in the Hf-N and Cr-N systems.