Internal friction of Ni and Fe covered with mineral oil films

Internal friction of some metals (e.g. Fe, Ni, Pd, Pt, steel) covered with a thin organic film (of oil, hydrocarbon or grease) reveals the presence of relaxation processes that do not correspond to the behaviour of either the metal or the organic material. These phenomena are connected with great changes in elastic and damping properties [complex Q-1(T) spectrum] of the surface metal layers and confirm the earlier hypothesis of hydrocarbon chemisorptive influence on metal and of hydrogen to metal diffusion (dissociative chemisorption of hydrocarbons). In the paper we present internal friction data in Fe and Ni covered with a mineral oil film together with measurements of the hydrogen content and rheological studies of the oil. The conclusions from Fe and steel experiments are compared with the first theoretical calculations for hydrogen in doped Fe structure –– i.e. calculations of absolute energy in density functional theory and local approximation with Harris functional.