The mechanical properties and surface topography of TiN/TiO2 coatings deposited by reactive magnetron sputtering on electron beam surface treated Ti5Al4V substrates were studied. The phase ...composition and crystallographic orientation were studied by X-ray diffraction. The hardness was investigated by nanoindentation test. The surface topography was evaluated using atomic force microscopy.
The results show that polycrystalline TiN and anatase - TiO2 phases are present in all cases. The electron beam treatment (EBT) leads to a more symmetrical distribution of the heights in comparison with the untreated substrates, as well as to increase in the surface roughness. The hardness of the Ti5Al4V substrates before and after the electron beam treatment process increases which is due to the transformation α+β to α′ martensitic microstructure occurring due to the fast cooling rate after the melting process. EBT leads to increase the surface roughness from 8 nm to 25 nm for the deposition of TiN/TiO2 coatings on Ti5Al4V. The treatment of Ti5Al4V substrates leads to decrease in the hardness of the coatings - from 7 GPa to 6 GPa. The scratch tests of the coated samples confirm the decrease of the friction coefficient as compared with the uncoated substrates.
•The mechanical properties and the topography of TiN/TiO2 coatings on Ti5Al4V substrates, deposited by reactive magnetron sputtering has been studied.•Polycrystalline TiN and anatase - TiO2 phases are present in all cases.•The electron beam treatment leads to an increase in the surface roughness.•The hardness of the Ti5Al4V substrates before and after the electron beam treatment process increase.•EBT of Ti5Al4V substrates leads to decrease in the hardness of the coatings - from 7 GPa to 6 GPa.
Titanium-based vacuum coatings, such as TiN and TiO2, are being widely used for functionalization of the surfaces and for forming protective surface layers for a number of applications. In this ...study, TiN/TiO2 coatings were deposited by two physical vacuum deposition (PVD) methods: cathodic-arc (for TiN) and glow-discharge (for TiO2) deposition. We studied the bilayer film composition, structure and properties by means of X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and scratch test analysis. The XRD spectrum indicated the presence of both anatase and rutile TiO2 phases, together with TiN reflections. The Ti 2p, O 1s and N 1s core level of XPS spectra in the depth of the oxide up to the oxide-nitride interface indicated intimate heterojunction between the layers. This results in a lower coefficient of friction and improved adhesion strength of the TiN/TiO2 film compared with pristine TiN coating.
The analytical calculation technique of high-altitude mast structures, reinforced with cable stretches, was developed in conditions of longitudinal-transverse bending. A numerical algorithm for ...deformed scheme calculating based on the stepwise loading of the finite element mast model was proposed. Comparative calculations of the masts selected versions with the use of developed software modules and SCAD and ANSYS software complexes are carried out. Parametric optimization problems of constant mast structures and two-step stiffness, with fixed and variable position of stretch marks were formed and solved. On the basis of the developed two-level algorithm, an effective design of a two-stage mast with an optimal arrangement of stretch marks was obtained.
The paper reports on the effect of the substrate temperature (350 °C, 380 °C and 420 °C) during reactive magnetron sputtering of a TiN film on the phase composition, texture and mechanical properties ...of TiN/TiO2 coatings on 304L stainless steel substrates. Pure Ti was used as a cathode source of Ti. The texture and unit cell parameters of both TiN and TiO2 phases of the coating are discussed in relation with the tribological properties and adhesion of the coating. The scratch tests performed showed that the nitride deposited at 380 °C, having the highest unit cell parameter and a predominant (111) texture, possessed the lowest friction coefficient (μ), tangential force and brittleness. The anatase-type TiO2 with predominant (101) pole density and increased c unit cell parameter showed the highest stability on the nitride deposited at 420 °C. The results indicated that the friction coefficient, tangential force and critical forces of fracture could be varied by controlling the coating deposition temperature.
The metallic implants represent a major class of the hard tissue replacement materials. In order to enhance the surface properties of the titanium alloys multicomponent coatings containing ceramic ...phases are employed to improve the tribological performance, corrosion resistance and biocompatibility. The mechanical properties (elastic modulus, necking region, loss of adhesion) of arc PVD TiN and TiN/TiO2 coatings deposited on unalloyed Ti (99 wt. %) foil were examined by nanoindentation, uniaxial tensile test while applying a new approach - using thermal imaging camera during the test. The hardness of the TiN coating reached values of 9649 MPa and 67 GPa, while that of the TiN/TiO2 was lowered down to 8774 MPa and 58.5 GPa which low values are closer to that of the cortical bone. The mechanical behavior of TiN/TiO2 coated material characterized it as a more plastic system indicating a good deformability while the TiN displayed more fragile behavior. There were no signs of loss of adhesion or loss of coating integrity up to maximum load for all tested TiN and TiN/TiO2 coated samples. The thermal analysis proves that the coated samples show lower thermal conductivity, which is very important for the performance of an endosseous dental implant for example.
In the particular study, the micropatterning of the Ti5Al4V alloy in as-received, solution treated and solution and precipitated condition was done using electron beam surface modification (EBSM) by ...scanning electron beam. The nanostructured TiN/TiO2 films were deposited over the EBSM Ti5Al4V substrates using dc magnetron sputtering and cathodic arc and glow-discharge methods. The electrochemical potentiodynamic tests were performed in Ringer saline at 37±0.05 °C and a pH of 5.7 in order to determine the corrosion resistance behavior of the coated and uncoated EBSM substrates as compared with the bare as-received, solution treated and solution and precipitated samples. The presented results gave an idea of the corrosion behavior of the examined implant systems in aggressive environment and external conditions close to the body right.
In order to obtain a proper and accelerated osseointegration process, continuous efforts for improving the surface of the implants have been made. The physical texture, structure and mechanical ...properties of the implant surface are known to be an important factor in bone-implant interaction. Trying to find a solution for weak osseointegration, new modification techniques should be used and examined. In the particular study, the Ti5Al4V and Ti6Al4V alloys with different initial structure and composition were vacuum heat treated at different technological parameters in order to obtain maximum strengthening. One and the same electron beam surface modified (EBSM) by scanning electron beam was subsequently carried out for both alloys and their surface characteristics and mechanical properties were revealed by metallographic analysis, roughness, XRD and hardness measurements. The results revealed that under the selected conditions of treatment, a specific wave-like topography was obtained. The mean grains' sizes, depth of the structural changes after the surface modification and hardness and crystal lattices' changes of both alloys was assessed depending on the differences in the composition, initial structural and mechanical characteristics of the alloys in the different heat-treated conditions.
The effect of the deposition technology of gradient TiN/TiO2 coatings, applied on Ti5Al4V substrate, on the phase composition and mechanical properties has been studied. The films have been applied ...by reactive magnetron sputtering and cathodic arc and glow-discharge techniques. The coatings' properties have been studied by X-ray diffraction (XRD) and nanoindentation tests. The results in the present study show that the application of both methods are capable to form polycrystalline TiN and TiO2. The coatings deposited by magnetron sputtering are monophasic and polycrystalline as TiO2 is in the form of anatase. Those, applied by cathodic arc and glow-discharge technique, TiO2 layer is in the form of double-phase structure of rutile and anatase. The measured hardness is similar for the coatings deposited via both methods. The hardness of magnetron sputtered coatings is 6.3±1.1 GPa. The values for coatings obtained by glow-discharge is 6.1±1.4 GPa.
Abstract
Titanium-based vacuum coatings, such as TiN and TiO
2
, are being widely used for functionalization of the surfaces and for forming protective surface layers for a number of applications. In ...this study, TiN/TiO
2
coatings were deposited by two physical vacuum deposition (PVD) methods: cathodic-arc (for TiN) and glow-discharge (for TiO
2
) deposition. We studied the bilayer film composition, structure and properties by means of X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and scratch test analysis. The XRD spectrum indicated the presence of both anatase and rutile TiO
2
phases, together with TiN reflections. The Ti 2p, O 1s and N 1s core level of XPS spectra in the depth of the oxide up to the oxide-nitride interface indicated intimate heterojunction between the layers. This results in a lower coefficient of friction and improved adhesion strength of the TiN/TiO
2
film compared with pristine TiN coating.
The paper presents the stiffness analysis and optimization of stepped columns constituting the core frame of the industrial building. The two-span cross section of a one- storey industrial building ...is investigated herein. The quasi-static calculation is performed using the limited load approximation method for the cross-section of the most loaded middle column. The critical Euler characteristic of the compressive longitudinal load is determined by the differential bending equations at the bifurcation instability in the column sections. The parameter optimization of the column cross-section is achieved through the nonlinear mathematical programming. The optimization of medium column cross-section is considered using the proposed calculation when setting a set of constraints for the optimization task.
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