Mossbauer and Structural Studies of f.c.c. Fe-Ni-C-based PVD CAE Coatings

The physical vapor deposition by cathode arc evaporation (PVD CAE) technique in microdrops mode was applied for deposition of austenitic nanocrystalline coatings of the Fe-31.2%Ni-2%Co-0.002%Y and Fe-31.4%Ni-2%Co-0.72%C-0.001%Y alloys on Cu substrate. The Mossbauer spectroscopy, X-ray diffraction analysis, transmission electron microscopy and dilatometry have been used to study the structure, magnetic order and thermal expansion of coatings. The estimated coherently diffracting domains values (CDD) and the TEM data testify that austenitic structure in coatings is dispersed and the presence of carbon intensifies the dispersion process of structural elements. Mossbauer analysis has shown that PVD CAE process results in the decomposition of an austenitic solid solution on microareas enriched both in Ni and Co and in Fe, which leads to the formation of a specific magnetic order characterized by existence of the ferromagnetic low-moment (FM LM) and antiferomagnetic high-moment (AM HM) phases and provides stable Invar properties of a coating at the 110-400 K temperatures.