Influence of the phase and elemental compositions and defect structure on the physicomechanical properties and tribotechnical characteristics of nanostructural Ti-Hf-Si-N coatings

A new approach to preparing superhard nanostructural Ti-Hf-Si-N coatings with high physicomechanical performance is developed and tested. Samples with Ti-Hf-Si-N nanocoatings obtained under different deposition conditions were investigated using nuclear physical analysis methods, namely, Rutherford backscattering, energy-dispersive X-ray analysis, secondary-ion mass spectrometry, and the slow positron beam method, as well as by conducting X-ray diffraction analysis and microhardness measurements and testing the tribotechnical performance of the films. It is found that the grain size varies from 3.9 to 10.0 nm depending on the bias applied to the substrate and the residual pressure in the chamber during nanocoating deposition. It is shown that the microhardness varies considerably (from 37.4 to 48.6 ± 1.2 GPa) according to the percentage and number of phases, grain size, and material transfer along nanograin boundaries and interfaces. In tribological tests of the Ti-Hf-Si-N nanocoatings, the mechanism of cohesive and adhesive fracture changes and the friction coefficient may vary from 0.46 to 0.15.