Formation of Multilayered $Ti-Hf-Si-N//NbN//Al_2O_3$ Coatings with High Physical and Mechanical Properties

This work presents the first results on forming of multi-layered superhard coatings $Ti-Hf-Si-N//NbN//Al_2O_3$ and their properties as well as structure. Microstructure, elemental and phase compositions of multi-layered coatings obtained by different methods were investigated. There were used such methods as: scanning electron microscopy EDS JEM-7000F microscope (with microanalysis) for research of cross-section of coatings, with subsequent Auger-electron spectroscopy, X-ray diffraction analysis, optical inverted microscope Olympus GX51, electron-ion microscopes Quanta 200 3D and Quanta 600 (scanning electron microscopy), equipped by the detector of X-ray radiation of the system PEGASUS 2000. It was stated that hardness of coatings has reached 56 GPa, and at the same time the factor of wearing during friction was the smallest - $2.571 \times 10^{-5}$. It was also noted that nitrogen pressure in the chamber at the deposition of the top layer significantly influences on the properties of samples. For example, the coefficient of friction at P=0.3 Pa from 0.2 at the beginning of track to 0.001 (during the tests), and at the pressure of nitrogen P=0.8 Pa, the coefficient of friction was equal to 0.314 at the beginning of track and 0.384 at the end (during the tests).