The research presented in this article concerns Zr–C gradient coatings that were deposited on HS6-5-2 steel by reactive magnetron sputtering from the Zr target in appropriately programmed C2H2 mass flow rate, resulting in various profiles of atomic carbon concentrations in the coating and consequently in spatial change of the properties (H, E, …) and behavior (H/E, H3/E2, We). In particular, the characteristic changes in hardness and Young’s modulus in the Zr–C coatings represented approximately by the bell curve, which has a maximum at the content of about 50 at.% C, were an inspiration to study the behavior of gradient coatings with carbon content in the range of 0–50 and 50–85 at.% with the same hardness change profile. The obtained results indicate that, firstly, the gradient of spatial changes in the coating composition increases their resistance to cohesive damage in comparison to non-gradient coatings, and, secondly, the results show that high hardness is a desired property but not sufficient to ensure adequate coating performance. Independently, an appropriate nano/microstructural structure is necessary, which determines their tribological behavior. In particular, in the case of the tested Zr–C coatings, the obtained results indicate that gradient coatings with a carbon content in the range of 50–85 at.% have better properties, characterized by the critical force Lc2, wear, coefficient of friction, H/E and H3/E2 ratios.
The objects of investigations were Cr/CrN multi-module coatings deposited using a cathodic arc evaporation method (CAPVD) on HS6-5-2C steel used as a substrates. Analysed coatings possesses seven Cr/CrN modules of fixed thickness each, with various thicknesses of Cr and CrN layers. Aiming for the evaluation of mechanical properties of tested multi-module Cr/CrN coatings, its hardness and Young's modulus were measured, on the basis of which were determined values of H/E and H 3 /E 2 ratios. Coatings wear and friction coefficients were measured in so called ball-on-disc test. The adhesion of the coatings was evaluated using scratch tester and was shown that main mechanism of adhesive damage of all tested coatings at higher loads are buckle spallations. All tested coatings are also characterised by good adhesion to the substrate, which is evidenced by the fact that cracked coating remains inside the scratch track. Basing on the analysis of obtained experimental results it was confirmed and explicitly shown that the thickness of the individual layers of Cr and CrN in the multi-module coating significantly affects its critical loads (in scratch test), fracture toughness and wear rate.
The research presented in this article concerns Zr–C coatings which were deposited on 304L steel by reactive magnetron sputtering from the Zr target in an Ar–C2H2 atmosphere at various acetylene flow rates, resulting in various atomic carbon concentrations in the coating. The article describes research covering the change in the antibacterial and anticorrosive properties of these coatings due to the change in their chemical and phase composition. The concentration of C in the coatings varied from 21 to 79 at.%. The coating morphology and the elemental distribution in individual coatings were characterized using field emission scanning electron microscopy with an energy-dispersive X-ray analytical system. X-ray diffraction and Raman spectroscopy were used to analyze their microstructure and phase composition. Parallel changes in the mechanical properties of the coatings were analyzed. Based on the obtained results, it was concluded that the wide possibility of shaping the mechanical properties of Zr–C coatings in combination with relatively good antibacterial properties after exceeding 50 at.% of carbon concentration in coatings and high protective potential of these coatings make them a good candidate for medical applications. In particular, corrosion tests showed the high anti-pitting potential of Zr–C coatings in the environment of artificial saliva.
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