Mathematical simulation of the layer growth kinetics during post-discharge nitriding: From early stage to quasi-steady stage

In this work a mathematical model has been developed in order to describe the kinetics of the compound layer formation during a post-discharge nitriding process. The model is related to a moving boundary value problem and considers different stages: diffusion process, formation of the layers, layer growth and quasi-stabilization of the layer growth. An analytical approximate solution of Goodman's type is sought and representations of the motion of the interfaces and the nitrogen concentration profiles are analyzed.