An approach for the identification of diffusion coefficients in the quasi-steady state of a post-discharge nitriding process

This work presents a model for the nitrogen concentration in iron nitride layers at the quasi-steady state and a method for computing the diffusion coefficients for post-discharge nitriding. The method is based upon an inverse problem of coefficient identification. The related moving boundary diffusion problem is modeled assuming constant diffusion coefficients and taking into account the observed qualitative behavior of the post-discharge nitriding process. To develop an algorithm for the identification of the diffusion coefficients the solution of the least square problem is transformed, with some algebraic manipulations, into a simple geometrical rule.