In the present work, the titanium carbonitride coatings were deposited by the reactive magnetron sputtering method at different substrate bias: 0, −70 V, and −100 V. The effect of the substrate bias on the structure, composition, and mechanical and tribological properties of titanium carbonitride coatings was studied. Scanning electron microscopy, nanoindentation, sliding wear test (ball-on-disk method), X-ray phase, and elemental analysis methods were used to evaluate the tribological properties and microstructure of the thin coatings. The dependencies obtained resulted in the determination of the most preferred mode of deposition by magnetron sputtering at a negative substrate bias in an atmosphere of argon–acetylene–nitrogen.
Coatings based on titanium carbonitride alloyed with zirconium and chromium were deposited using the method of reactive magnetron sputtering on the surface of titanium VT1–0. The effect of alloying titanium carbonitride with zirconium and chromium on the tribo- and corrosion properties of the coating has been studied. Coatings with different compositions were formed by changing the ratio of alloying elements to titanium in a single target. To study the obtained coatings, a scanning electron microscopy, nanoindentation, sliding wear test (ball on disk method), and corrosion tests in 0.5 M Na2SO4 and 30% NaCl solution were used. As a result of wear and corrosion tests, friction coefficients, mass index, and corrosion rate of alloyed and pure titanium carbonitride coatings were obtained. The average coefficient of friction of the coatings varied in the range of 0.17–0.31. The values of nanohardness are determined depending on the composition of the coatings. From corrosion data, it is determined that TiCrCN and TiZrCN coatings exhibit better corrosion properties compared to TiCN coatings. As a result of the dependences obtained, the preferred composition of the coating, the most resistant to wear and corrosion damage, was revealed.
The paper offers the measuring results for hydrogen permeability of the membranes made of 40 μm thick tantalum foil covered with a metallic film with different thicknesses on one side. The measurements were performed when the membranes were in contact with a commercial argon and hydrogen gases mixed at the ratio of 1/5 at an overpressure of 500 kPa and at 580-585°C. It is shown that films of Mo, Re, W, Cu, Co, and Ni metals deposited on the tantalum membrane surface from the side facing a hydrogen-containing gas mixture increase its hydrogen permeability. The effect degree of these metals increases in the specified row from left to right. The effect on the hydrogen permeability of tantalum membranes, comparable to and superior to the deposition of a Pd film, exerts the deposition of Cu, Co, and Ni films. It is explained by the high hydrogen permeability level of these metals and the catalytic activity of their surface that results in intense hydrogen dissociation. The value of the hydrogen permeability of the membranes naturally increases with a thickness decrease of metallic films, however, it is obvious that this behavior is not linear. The hydrogen permeability of membranes with Cu, Co, and Ni films decreases over time, that is explained by the oxygen segregation at the Ta membrane/film interface, as well as by the processes on the membrane surface in contact with the gas mixture. The nature of these processes should be studies since the lower oxides of these metals are reduced by hydrogen at this temperature.
Purpose: The main goal of the work was to find the interconnection between the high-frequency magnetron sputtering parameters and the adhesion properties of CaP coatings formed on the surface of titanium substrate. Methods: Calcium-phosphate coatings, similar in composition to hydroxyapatite, were generated by high-frequency magnetron sputtering on titanium substrate at different values of high-frequency specific power over times of one and two hours. Afterwards, the generated coatings were studied using the method of X-ray phase analysis, and sclerometric tests (scratch test) were carried out. The adhesion strength of the deposited coatings was tested for different coating thicknesses from 0.45 to 1.1 × 10–3 mm. Results: According to the results of sclerometry, it was found that with an increase in the high-frequency specific power of plasma to 3.15 W/cm2, the adhesion strength of the calcium-phosphate coating also increases. For all the coatings, the critical loads at which the coating completely exfoliated from the substrate were determined. Conclusions: According to the research results, the most optimal conditions for obtaining high-adhesive calcium-phosphate coatings were determined.
The research represents a newly-developed simple method to apply hydroxyapatite by gas-dynamic spraying. The hydroxyapatite coating formed on VT1-0 titanium were obtained following the mechanochemical interaction of hydroxyapatite and titanium with gas-dynamic spraying. The article proposes the phase composition, surface morphology, and roughness of these coatings. The surface morphology of the hydroxyapatite coating had a porous structure. The transverse sections of coatings were researched to study the interaction of hydroxyapatite with a titanium base. It was shown that the coatings mainly form in the titanium bedding depressions. Analyzing the roughness parameter Ra of hydroxyapatite coatings made it possible to conclude that the samples obtained fell almost within the same limits. These data are within the roughness optimum (Ra = 2-3 μm) of artificial surfaces aimed to manifest the best human osteogenic properties. The analyzed phase composition enabled to establish the fact that the hydroxyapatite layer composition does not change significantly after spraying that is important for biomedical use.
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