[en] A phase composition of ∼10 nm thick Fe film placed on the silicon substrate with 200 nm thick SiO_x layer after annealing in vacuum and in H₂+CH₄ was investigated using Conversion Electron Moessbauer spectroscopy (CEMS). CEMS spectra show that the original iron film was formed by Fe³⁺ phase. This phase is stable after the annealing in vacuum or in H₂+CH₄ below 500 degree sign C but formation of phases with Fe²⁺ and Fe⁰(γ-Fe and α-Fe) was observed after annealing at 500 degree sign C and higher temperatures. Formation of fayalite (Fe₂SiO₄) occurred during vacuum annealing at 700 degree sign C. SEM and CEMS study of the sample with grown multi-walled carbon nanotubes shows that the dominating part of iron atoms is present in Fe₃C and Fe₅C₂ carbide phases. Besides their stoichiometric forms, the spectrum components which can be ascribed to the amorphous Fe_5-xC_2+x carbides, γ-Fe, and Fe³⁺ were observed.