J. Phys. IV France
Volume 120, December 2004
Page(s) 21 - 23

J. Phys. IV France 120 (2004) 21-23

DOI: 10.1051/jp4:2004120002

Modelling nitriding of iron: From thermodynamics to residual stress

M.A.J. Somers

The Technical University of Denmark, Department of Manufacturing Engineering and Management, Kemitorvet b.204, 2800 Kgs. Lyngby, Denmark

The present article presents a few selected aspects of the modelling of gaseous nitriding of pure iron. After descriptions of the thermodynamics of the gas phase and the reactions at the gas/solid interface, a model description of the thermodynamics of $\gamma'-Fe_{\rm 4}N{\rm 1-x}$ is given, which takes the long-range ordering of nitrogen atoms into account. Subsequently, the kinetics of nucleation and growth of iron nitride layers is described in terms of the rates of the surface reactions and solid state diffusion. Thereafter, the mechanisms of stress generation in $\gamma'-Fe_{\rm 4}N{\rm 1-x}$ layers during nitriding are summarized. Finally, the model for stress development in $\gamma'-Fe_{\rm 4}N{\rm 1-x}$ layers is compared with published experimental work.

© EDP Sciences 2004