[en] Laminated iron foils have been implanted with 50 keV fluorine ions at different doses between 1 10¹⁶ ions/cm² and 2 10¹⁷ ions/cm². Nuclear resonant reactions are used for the determination of concentration depth profiles. Gamma-rays from the ¹⁹F(p,αγ)¹⁶O* reaction are detected and the advantage of low energy resonances is demonstrated, namely the 340.46 keV resonance has the advantage of high sensitivity and low background making possible large depth investigations (2500 A). Different effects are investigated: surface roughness, total dose, stopping power, thermal diffusion, corrosion, ... Samples are treated at different temperature between 100 and 450⁰C, the diffusion of fluorine is observed with the 340.46 keV resonance, the sensitivity is good and the background is very low. Above 450⁰C a rapid oxidation of the surface is observed by nuclear resonant scattering. Depth profile measurements indicate that the oxidation process is responsible for a migration of the fluorine ions. (author)