Local structure of titanium nitride-based coatings

The fine structure of X-ray absorption spectra near the K edge and the extended fine structure of X-ray absorption for titanium, copper, and chromium in nanocrystalline coatings based on titanium nitride doped with copper, chromium, and silicon are experimentally studied. The samples are prepared by the evaporation of composite cathodes using the vacuum arc plasma-assisted method. The parameters of the local environment of titanium, copper, and chromium atoms in the structures of the samples under study are calculated. It is established that the presence of a copper impurity in the coating of no more than 12% in amount leads to a slight increase in the Ti–N distance in comparison with the titanium sample, whereas doping with silicon leads, on the contrary, to a decrease in the bond length. The measurement results for the K absorption edges of copper and chromium confirm that the doping elements are concentrated at the edges of the growing titanium-nitride crystallite and determine its size, which corresponds to the sizes of the coherent-scattering region of 40–50 nm.