The dissociative adsorption of nitrogen on Fe(12, 1, 0) was found to induce an increase in the density of steps and finally cause faceting of the surface with large nitrogen exposures. The epitaxial relationship between α-Fe and Fe4N in certain crystallographic directions could account for the observed structural changes.

Nitrogen-Induced Reconstruction of a Stepped Iron Surface. P.A.Dowben, M.Grunze, R.G.Jones: Surface Science, 1981, 109[2], L519-26