In the present paper we carried out several experiments in oxygen or dry air, at low temperature of some metallic samples. In order to be able to extend or estimate the corrosion phenomenon we made use of the modelling of oxygen diffusion through rust layers (oxides) and of
solving the parabolic equations of diffusion, respectively. The diffusion equation is important for modelling the oxygen diffusion within biological systems and for modelling the neutron flux from nuclear reactors.