Origin of nitrogen depth profiles after laser nitriding of iron

In spite of its technological importance, the basic mechanisms of laser nitriding of metals and alloys are hardly understood. The nitrogen depth profiles achieved by laser nitriding of pure iron were measured with high accuracy by resonant nuclear reaction analysis and described by two superimposed diffusion profiles. Using simple estimates, together with the results of marker experiments and laser treatments in N-15-isotopically enriched atmospheres, the development of these profiles with the number of pulses can be simulated in excellent agreement with the experimental results. (C) 1999 American Institute of Physics. [S0003-6951(99)04201-1].