Mössbauer Study of Iron Carbides Formed by Thermal Vacuum Deposition.

Nanoscale coatings formed by thermal vacuum deposition of metal on an aluminum substrate have been investigated by Mössbauer spectroscopy, X-ray diffraction (XRD) analysis, and electron microscopy. The film coatings have been grown by depositing enriched ⁵⁷Fe in a magnetron vacuum chamber at a residual atmospheric pressure. It is shown that carbon penetration occurs over grain boundaries and inhomogeneities of interboundary formations, and an amorphous phase is formed during deposition of fine-grained ⁵⁷Fe. After annealing at a temperature of 500°C, the amorphous structure is crystallized and a monophase (cementite Fе₃С) is formed. High-temperature annealing leads to the formation of ferrite α-Fе(C) and graphite due to the decrease in the Fе₃С content, according to the equilibrium phase diagram of the Fе–C system. [ABSTRACT FROM AUTHOR]