Multilayered Nano-Microcomposite Ti-Al-N/TiN/$Al_2O_3$ Coatings. Their Structure and Properties

This paper presents the first results on formation and study of structure and properties of micro- and nanocomposite combined coatings. By means of modeling the deposition processes (deposition conditions, current density-discharge, plasma composition and density, voltage) we formed the three-layer nanocomposite coatings of Ti-Al-N/Ti-N/$Al_2O_3$. The coating composition, structure and properties were studied using physical and nuclear-physical methods. The Rutherford proton and helium ion backscattering, scanning electron microscopy with microanalysis, grazing incidence X-ray diffraction, as well as nanohardness tests (hardness) were used. Measurements of wear resistance and corrosion resistance in NaCl, HCl and $H_2SO_4$ solutions were also performed. For testing mechanical properties such characteristics of layered structures as hardness H, elastic modulus E: $H^3//E^2$ etc. were measured. It is demonstrated that the formed three-layer nanocomposite coatings have hardness of 32 to 36 GPa and elastic modulus of 328 ± 18 to 364 ± 14 GPa. Its wear resistance (cylinder-surface friction) increased by factor of 17 to 25 in comparison with the substrate (stainless steel). The layers thickness was in the range of 56-120 μm.