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In this study, multi-element nitride coatings composed of (Ti, Cr, Cu, Al, Si)N were synthesized on H13 tool steel using cathodic arc deposition (CAD) technology. The N2/Ar flow ratio varied from 0 to 2 as the experimental parameter, and two targets, Ti-Cr-Cu and Al-Si alloys, were utilized simultaneously. The impact of the gas flow ratio on the coatings' abrasion properties was investigated, focusing on aspects, such as chemical composition, adhesion, hardness, and wear behavior. The experimental findings indicate that the coated specimens with a nitrogen reaction exhibit superior hardness and abrasion resistance compared to those without nitrogen use. While the surface roughness of the specimens tends to increase slightly with a higher N2/Ar ratio, the coating demonstrates improved hardness, adhesion, and abrasion resistance performance. In summary, the wear-resistant characteristics of H13 tool steel can be significantly enhanced when applying a CAD-(Ti, Cr, Cu, Al, Si)N film with a flow ratio of N2/Ar = 2. [ABSTRACT FROM AUTHOR]

Tribological properties of TiN and CrN coatings deposited by cathodic arc method at three different bias potentials -50, -150 and -300V on Ti-6Al-4V alloy in pair with alumina have been investigated. X-ray diffraction analysis showed that single-phase textured cubic nitrides of TiN and CrN were formed in these coatings. It is shown that the friction coefficient of the coatings is practically equal to that established for the Ti6Al4V alloy, but the wear rate is more than an order of magnitude lower than for the titanium alloy substrate. Coatings deposited at a potential of -50 V show optimal tribological properties at temperatures 20 and 500°C. Friction coefficients for TiN coatings are 0.4-0.8 at 20°C and 0,75 at 500°C; for CrN coatings they are 0.5 at 20°C and 0,7 at 500°C. Wear rates for TiN coatings are 0.86·10-5 мм3/Нм at 20°C and 3.56·10-5 мм3/Нм at 500°C; for CrN coatings they are 1.43·10-5 мм3/Нм at 20°C and 7.13·10-5 мм3/Нм at 500°C.

Tribological properties of TiN and CrN coatings deposited by cathodic arc method at three different bias potentials -50, -150 and - 300V on Ti-6Al-4V alloy in pair with alumina have been investigated. X-ray diffraction analysis showed that single-phase textured cubic nitrides of TiN and CrN were formed in these coatings. It is shown that the friction coefficient of the coatings is practically equal to that established for the Ti6Al4V alloy, but the wear rate is more than an order of magnitude lower than for the titanium alloy substrate. Coatings deposited at a potential of -50 V show optimal tribological properties at temperatures 20 and 500°C. Friction coefficients for TiN coatings are 0.4-0.8 at 20°C and 0,75 at 500°C; for CrN coatings they are 0.5 at 20°C and 0,7 at 500°C. Wear rates for TiN coatings are 0.86·10-5 MM³/HM at 20°C and 3.56·10-5 MM³/HM at 500°C; for CrN coatings they are 1.43·10-5 MM³/HM at 20°C and 7.13·10-5 MM³/HM at 500°C. [ABSTRACT FROM AUTHOR]

The nanocrystalline titanium nitride (TiN) films were deposited on fluorine doped tin oxide (FTO) coated glass substrates for the first time by cathodic arc deposition. The crystalline phase and orientation, growth morphology, surface roughness, hardness, scratch adhesion, electrical resistivity, optical absorption and bandgap of the TiN films were investigated. The GI-XRD confirmed the formation of cubic TiN and crystallographic orientation growth. The 2150 nm thick TiN film showed (111) orientation due to columnar growth patterns, while the 650 nm TiN film formed with the (200) orientation. The grain size of TiN films was 50–200 nm by FESEM and AFM analyses, and it was formed as elongated nanocrystals of 65–125 nm width and 120–250 nm lengths. The microhardness of the 650, 1000 and 2150 nm TiN thin films was measured to be 836, 943 and 1281 HV 0.05 respectively. The scratch adhesion test demonstrated a good adhesive strength up to a critical load of 10 N and beyond the delamination occurred. The electrical resistivity of TiN film found to vary with thickness, the 650 nm TiN film showed a low resistivity of 16 × 10-6 Ω cm, which is comparable with the electrical resistivity of platinum and magnetron sputtered TiN film. The UV-Vis-NIR diffused reflectance spectroscopic studies of the TiN thin film showed a sharp absorption at 448 nm due to plasmon absorption and Tauc plot showed direct band gap of 2.1 eV. The results demonstrated that cathodic arc deposited nanocrystalline TiN thin film deposited on FTO glass substrate can be used as counter electrode for dye sensitized solar cell (DSSC) applications. [ABSTRACT FROM AUTHOR]

The phase composition of coatings based on the Ti–Al–C system has been investigated on an X‑ray diffractometer and a synchrotron radiation source. The Ti–Al–C coating was deposited onto molybdenum and titanium samples by cathodic arc deposition from two single-component titanium and aluminum cathodes in a mixture of acetylene and argon. A study of the phase composition showed that the formation of the Ti2AlC and Ti2C phases depends on the heat treatment regime. The phase stability of the coating during the heating of the sample to 1500°C in vacuum was studied using synchrotron radiation. The deposited coating has an amorphous structure, which crystallizes after annealing in vacuum, forming the Ti2AlC and Ti2C phases and Ti–Al intermetallic compounds. [ABSTRACT FROM AUTHOR]

This paper presents the results of the investigation of a multilayer TiAlSiN/AlSiN coating. A novel coating architecture with a period consisting of nanocomposite sublayers of TiAlSiN and AlSiN was developed. We discovered that the combination of a harder sublayer with a more elastic one allows for obtaining a suitable combination of superhardness and enhanced toughness. The coating was deposited by cathodic arc technology. The EDS, XRD, and XRS analyses revealed that the nanocomposite structure is composed of TiAlSiN and AlSiN nanocrystallites, with sizes of 12–13 nm and 4–5 nm, respectively. The nanograin phase is incorporated in an amorphous Si3N4 matrix. The achieved structure causes the presence of four factors contributing to the hardness increase: nanocomposition, solid solution, refinement hardening, and the formation of many interfaces. An instrumented indentation test was used to investigate the mechanical properties. The developed coating possesses a superhardness of 49.5 GPa and a low elastic modulus of 430 GPa, resulting in an improved elastic strain resistance of 0.11, a plastic deformation resistance of 0.58 GPa, and an elastic recovery of 68%. These results imply that the developed coating combines high stability with mechanical degradation under external influence and provides an improved ability to absorb energy at deformation before fracture, and high elastic recovery. The investigation of the effect of the period modulation on the structure, composition, and mechanical properties of the nanocomposite multilayer TiAlSiN/AlSiN coating showed that the superhardness was due to the nanocomposite and solid solution hardening rather than the increased number of interfaces. The demonstrated combination of superhardness with high elasticity and improved toughness determines the developed nanocomposite TiAlSiN/AlSiN coating as very suitable for industrial applications such as high speed and dry machining. [ABSTRACT FROM AUTHOR]

We investigate the effects of substrate bias on cathodic arc deposition of Cr coatings without external substrate heating at four different substrate bias levels, floating, −30, −50, and −70 V. After 10 min of deposition, the substrate temperature reaches 180, 210, 230, and 260 °C for floating potential, −30, −50, and −70 V, respectively. Time-of-flight energy elastic recoil detection analysis shows that all grown coatings are of high purity, with no coating containing more than 0.2 at.% of C and/or O. Increasing the substrate bias also reduces the number of macroparticles, steers the texture from preferred [110]- to [100]-orientation and induces a residual compressive stress of ∼450 MPa in the coatings. The hardness of the coatings remains at a constant 7.5 GPa irrespective of the substrate bias. The four-point probe resistivity of the grown coatings is 15–17 μΩcm regardless of substrate bias, close to the 12.9 μΩcm of bulk Cr.

The objective of this study was to investigate the effect of varying bias parameters (−50 V, −100 V, and −150 V) on the properties of TiN/CrN multilayer films deposited on Ti-6Al-4V alloy using the cathodic arc deposition (CAD) technique. The deposited films were characterized for their composition, structure, morphology, thickness, adhesion, and hardness. Wear and polarization tests were also conducted to determine the optimal bias condition for wear and corrosion resistance. The results showed that the TiN/CrN films possessed a nano-multilayered structure comprising TiN and CrN phases. The hard coating significantly increased the surface hardness of Ti-6Al-4V alloy up to three–five times. The coated specimens demonstrated superior wear resistance compared to the uncoated, with the −150 V specimen exhibiting the least wear rate. Furthermore, the −150 V specimen had the highest polarization impedance value, indicating the best corrosion resistance compared to the other bias conditions. In short, the use of CAD-coated TiN/CrN multilayer film enhanced the surface properties of Ti-6Al-4V alloy, with the best wear and corrosion resistance achieved at −150 V bias. These novel findings have significant implications for improving the performance and durability of Ti-6Al-4V alloy components in various industrial applications. [ABSTRACT FROM AUTHOR]

This work studied the sliding wear performance of TiAl-based nitride coatings synthesized on austempered ductile iron (ADI) by cathodic arc deposition (CAD) and plasma-based ion implantation and deposition (PBIID). Monolayer CAD TiAlN films and bilayer CAD and PBIID TiAl/TiAlN films deposited on an experimental device were analyzed and benchmarked against a commercial bilayer CAD film. Sliding wear was evaluated in a pin–on–disc tribometer. Two test conditions were employed, one intended to prevent damage (low load, short distance) and another intended to promote damage (higher load, longer distance). Regarding low load tests, all coated samples showed friction coefficients of 0.40–0.45 and negligible wear. Regarding high load tests, all coated variants exhibited lower or equal disc and pin wear rates with respect to uncoated ADI. In addition, coated samples displayed steady-state friction coefficients between 0.2 and 0.6 while uncoated ADI steady-state coefficients between 0.6 and 0.85. [ABSTRACT FROM AUTHOR]

The results of a study of the change in the microhardness and chemical composition in the surface layers of two-phase titanium alloys after complex modification in high-density plasma are presented. Complex surface modification in a single vacuum cycle includes the following operations: ion cleaning of the surface and heating of the sample in argon plasma, deposition of nitride-forming elements onto the surface, and low-temperature (no more than 550°C) nitriding in high-density plasma. The phase and elemental composition, microhardness of the surface layer, and roughness are investigated to determine the effect of the modes of complex modification on the characteristics of the surface layers. Complex surface modification results in a significant, up to twofold, increase in the microhardness of the modified layer. The change in the microhardness is associated with the formation of an interstitial solid solution as well as titanium nitrides containing dispersed particles of nitrides of titanium and aluminum intermetallic compounds. [ABSTRACT FROM AUTHOR]

By cathodic arc deposition, the effects of the magnetic field, working pressure, inner-wall structure, and cross-section area of the magnetic-filter duct on the macroparticle (MP) distribution were investigated with a high-entropy alloy target. The MP density increased with the density of the plasma beam transporting through the filter duct, which was increased by the magnetic field or working pressure. In order to reduce the MP density, equally spaced circumferential Cu-sheet baffle and lining of 304-stainless-steel wire mesh were used as the inner-wall structure, respectively, but the improvement was limited. However, inserting an Al foil disk with a round opening for the passage of the main plasma stream at the bend position of the duct remarkably reduced the area fraction of the MPs from 4.8% to 0.6%. These results demonstrate that the main transport mechanism of the MPs was the entrainment in the plasma beam through the duct. In addition, reducing the cross section of the filter duct was suggested to be an effective method to reduce MPs. This method could be utilized for high-MP generation targets such as high-entropy alloys. [ABSTRACT FROM AUTHOR]

The use of lightweight materials, such as ultra-high-strength aluminium alloys, is in high demand in the automotive and aerospace industries where weight savings are critical. The tool materials used for high-speed cutting of these aluminium alloys are subjected to severe conditions that promote premature failure of cutting tools. The application of polycrystalline diamond (PCD) coatings provides cutting tools with increased mechanical and thermal fatigue resistance and improved tribological performance. Despite these good properties, their high cost remains a major limitation in this sector. Super-hard Diamond-Like Carbon (DLC) coatings offer a technologically and economically feasible alternative to PCD-coated tools for cutting and machining non-ferrous materials. In this paper, the machining performance of coated and un-coated hard metal inserts in the turning of 7075 aluminium alloy has been explored. The surface quality of machined parts, the cutting tool wear resistance and the vibrations generated during turning of un-coated, PCD and super-hard thin DLC coatings on tungsten carbide inserts were compared. The results obtained demonstrate that DLC coatings are a potentially interesting alternative to PCD coatings for machining ultra-high-strength aluminium alloys, where surface component finish is a key factor. [ABSTRACT FROM AUTHOR]

Al-Cr and Al-Cr-Si composite cathodes were obtained by the hot compaction of aluminum, chromium, and silicon powder mixtures. The phase transformations in the surface layer of the Al-Cr-Si composite cathodes subjected to the arc heating were considered. The elemental and phase compositions of the modified cathodes' surfaces were studied using X-ray diffraction, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The effect of the silicon addition on the structural evolution in the cathode surface during arc evaporation is shown. It was found that an arc impact on the cathode surface resulted in the melting and consequent crystallization of the multiphase mixture of intermetallic compounds and eutectic in the cathode surface layer. Cathode surface layers were found to be depleted of aluminum and silicon due to the ejection of these elements in drop form from the Al-Si liquid layer on the cathode surface. This can result in the change in the elements ratio in the deposited coating as compared with that in the cathode and thus influence the coated tools' durability. [ABSTRACT FROM AUTHOR]

In this study the results of investigating the change in the chemical composition in the surface layers of cutting tools at the beginning of machining are presented. To describe this change, physical modeling, imitating the initial stage of machining and wear, is performed. The investigated samples made of TT8K6 alloy with a Ti–Al–N coating is thermally and mechanically loaded at 700°C by an applied pressure of 0.5 GPa for 20 minutes. This corresponds to the thermal and mechanical loads on the coating during machining. The change in the chemical composition in the surface layers of coated tools are investigated by glow-discharge optical emission spectroscopy analysis. A variation in the titanium, aluminum and oxygen content in the surface layers after modeling is described. Qualitative elemental composition profiles are presented. In addition, the microstructure of the samples obtained by scanning electron microscopy is presented. Element distribution maps are obtained. [ABSTRACT FROM AUTHOR]

This work aimed to evaluate the effect of V addition into TiSiN coatings deposited by an industrial-scale cathodic arc evaporation system on the structure and mechanical-tribological properties. X-ray diffraction patterns and Raman spectra confirm the formation of a solid solution presenting the fcc NaCl-type structure without a preferred orientation for both TiSiN and TiSiVN coatings. The addition of V did not affect the coating's hardness but induces a half-reduction in the coefficient of friction during the dry sliding tests. The wear mechanism changed from abrasive to mild-adhesive due to the inclusion of V, suggesting a reduction in the wear rate that might be of interest for dry cutting tools. [ABSTRACT FROM AUTHOR]

In this paper, we present a comparative study of tribological properties of TiN coatings deposited by low-voltage electron beam evaporation, magnetron sputtering and cathodic arc deposition. The correlation of tribological behavior of these coatings with their intrinsic properties and friction condition was studied. The influence of surface topography and the surrounding atmosphere was analyzed in more detail. We limited ourselves to the investigation of tribological processes that take place in the initial phase of the sliding test (the first 1000 cycles). A significant difference in the initial phase of the sliding test of three types of TiN coatings was observed. We found that nodular defects on the coating surface have an important role in this stage of the sliding test. The tribological response of TiN coatings, prepared by cathodic arc deposition, is also affected by the metal droplets on the coating surface, as well as those incorporated in the coating itself. Namely, the soft metal droplets increase the adhesion component of friction. The wear rates increased with the surface roughness of TiN coatings, the most for coatings prepared by cathodic arc deposition. The influences of post-polishing of the coating and the surrounding atmosphere were also investigated. The sliding tests on different types of TiN coatings were conducted in ambient air, oxygen and nitrogen. While oxygen promotes tribo-chemical reactions at the contact surface of the coating, nitrogen suppresses them. We found that the wear rate measured in ambient air, compared with that in an oxygen atmosphere, was lower. The difference is probably due to the influence of humidity in the ambient air. On the other hand, wear rates measured in a nitrogen atmosphere were much lower in comparison with those measured in an oxygen or ambient air atmosphere. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of varying bias parameters (−50 V, −100 V, and −150 V) on the properties of TiN/CrN multilayer films deposited on Ti-6Al-4V alloy using the cathodic arc deposition (CAD) technique. The deposited films were characterized for their composition, structure, morphology, thickness, adhesion, and hardness. Wear and polarization tests were also conducted to determine the optimal bias condition for wear and corrosion resistance. The results showed that the TiN/CrN films possessed a nano-multilayered structure comprising TiN and CrN phases. The hard coating significantly increased the surface hardness of Ti-6Al-4V alloy up to three–five times. The coated specimens demonstrated superior wear resistance compared to the uncoated, with the −150 V specimen exhibiting the least wear rate. Furthermore, the −150 V specimen had the highest polarization impedance value, indicating the best corrosion resistance compared to the other bias conditions. In short, the use of CAD-coated TiN/CrN multilayer film enhanced the surface properties of Ti-6Al-4V alloy, with the best wear and corrosion resistance achieved at −150 V bias. These novel findings have significant implications for improving the performance and durability of Ti-6Al-4V alloy components in various industrial applications.

The scientific interest in the investigation of nitride composites as protecting materials in tool and machining industries intensively increases. The good oxidation resistance of CrN single-layer films and high melting point, good chemical and thermal resistance of ZrN compound are motive factors for designing of multilayer composites composed of these metal nitrides. The suggested advantages of ZrN/CrN multilayer coatings as structural materials are the high-temperature resistance, high density and extreme hardness compared to the metal-nitride systems. Experimental ZrN/CrN multilayer coatings were deposited on AISI 321 steel substrates by using a cathodic arc evaporation device equipped with two high-purity metal Cr and Zr targets. Structural, chemical and morphological characteristics together with mechanical properties of multilayer composites were analyzed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and Vickers hardness tester. SEM analysis revealed an increase of roughness and concentration of the droplets on the surface of the coatings when negative bias potential decreased to -70 V. The results of data obtained from the X-ray analysis showed (200) and (111) plane for ZrN and Cr2N phases as the most intense. The peak positions of ZrN were shifted towards lower diffraction angles comparing with bulk values and indicated a decrease of the inter-planar distance and formation of compressive stresses. The calculated lattice strain values in the ZrN were higher than those of the CrN, indicated a greater presence of dislocations and defects in the lattice of ZrN. The averaged crystallite sizes in ZrN and CrN layers were 11-14 and 7-12 nm, respectively. The maximum value of the Vickers microhardness was found to be 6600HV0.01 that is 2.1 and 1.8 times greater than the corresponding values of binary CrN and ZrN coatings.

The paper deals with the synthesis of coating based on molybdenum and molybdenum nitrides using cathodic arc deposition without the plasma assistance. The properties, composition and structure of the obtained coating are studied in detail. It is found that the nitrogen partial pressure in the gas mixture affects the nitrogen concentration in the coatings and the properties of the latter. The structure and phase composition of the coatings synthesized at a low partial pressure, are investigated by using the X-ray diffraction analysis and scanning electron microscopy. [ABSTRACT FROM AUTHOR]

The use of lightweight materials, such as ultra-high-strength aluminium alloys, is in high demand in the automotive and aerospace industries where weight savings are critical. The tool materials used for high-speed cutting of these aluminium alloys are subjected to severe conditions that promote premature failure of cutting tools. The application of polycrystalline diamond (PCD) coatings provides cutting tools with increased mechanical and thermal fatigue resistance and improved tribological performance. Despite these good properties, their high cost remains a major limitation in this sector. Super-hard Diamond-Like Carbon (DLC) coatings offer a technologically and economically feasible alternative to PCD-coated tools for cutting and machining non-ferrous materials. In this paper, the machining performance of coated and un-coated hard metal inserts in the turning of 7075 aluminium alloy has been explored. The surface quality of machined parts, the cutting tool wear resistance and the vibrations generated during turning of un-coated, PCD and super-hard thin DLC coatings on tungsten carbide inserts were compared. The results obtained demonstrate that DLC coatings are a potentially interesting alternative to PCD coatings for machining ultra-high-strength aluminium alloys, where surface component finish is a key factor.

NiCrAlY coating was deposited on the IN-738LC Ni-based superalloy by cathodic arc deposition at the substrate temperatures of 400°C and 700°C. The effects of the substrate temperature on the microstructure and the isothermal oxidation behaviour of the coatings were then investigated. SEM image and XRD analysis were used to characterize the deposited coatings. It was found that when the substrate temperature was raised from 400°C to 700°C, the degree of coating crystallinity was increased from 23% to 58%. After the 20-hr oxidation at 1000°C in air, the γ′-depletion layer was formed in the substrate. The growth rate constants of the γ′-depletion layer after the 100-hr oxidation were 1.3 × 10−4 μm (sb)−1 and 6.4 × 10−5 μm (sb)−1 for the deposited coatings at 400°C and 700°C, respectively. The results, therefore, indicated that with increasing the substrate temperature from 400°C to 700°C, the oxidation resistance was improved. [ABSTRACT FROM AUTHOR]

Cathodic arc deposition, in spite of all its advantages, including feasible alloying evaporation, high deposition rate and considerable adhesion, faces the challenge of macroparticles. In this article, the influence of arched and through magnetic field configurations on the reduction in the number and size of the macroparticles of the Al coating, arc voltage and ion current density was investigated. Scanning electron microscopy was used to investigate the macroparticles of the coating. The number of macroparticles in the arched magnetic field was decreased from 3.5 × 10−3 to 2.2 × 10−3 µm−2, on the other hand in the through magnetic field, it was reduced from 3.5 × 10−3 to 2.6 × 10−3 µm−2. So with increasing the intensity of the magnetic field from 0 to 120 G, the ion current density was decreased from 2.36 to 1.3 mA cm−2 in the arched magnetic field configuration, however, it did not change considerably for the through one. [ABSTRACT FROM AUTHOR]

Molybdenum-containing amorphous carbon (a-C:Mo) thin films were prepared using a dual-cathode filtered cathodic arc plasma source with a molybdenum and a carbon (graphite) cathode. The Mo content in the films was controlled by varying the deposition pulse ratio of Mo and C. Film sheet resistance was measured in situ at process temperature, which was close to room temperature, as well as ex situ as a function of temperature (300-515 K) in ambient air. Film resistivity and electrical activation energy were derived for different Mo and C ratios and substrate bias. Film thickness was in the range 8-28 nm. Film resistivity varied from 3.55x10-4 Omega m to 2.27x10-6 Omega m when the Mo/C pulse ratio was increased from 0.05 to 0.4, with no substrate bias applied. With carbon-selective bias, the film resistivity was in the range of 4.59x10-2 and 4.05 Omega m at a Mo/C pulse ratio of 0.05. The electrical activation energy decreased from 3.80x10-2 to 3.36x10-4 eV when the Mo/C pulse ratio was increased in the absence of bias, and from 0.19 to 0.14 eV for carbon-selective bias conditions. The resistivity of the film shifts systematically with the amounts of Mo and upon application of substrate bias voltage. The intensity ratio of the Raman D-peak and G-peak (ID/IG) correlated with the pre-exponential factor (sigma 0) which included charge carrier density and density of states.

NiCrAlY coating was deposited on the Ni-base superalloy in the cathodic arc deposition process. The isothermal oxidation test was carried out at 1000°C in air. The cross-section of the coatings was studied by the field emission scanning microscope electron and energy dispersive spectroscopy. The formation and growth of the internal oxide were addressed during the high temperature oxidation. The outward diffusion of Ti occurred from the substrate to the coating, leading to the formation of TiO2 beneath the thermally-grown oxide scale. Thermodynamic measurements of TiO2 formation were performed and the role of the internal oxide in the formation of TiO2 was determined. [ABSTRACT FROM AUTHOR]

In this work, the influence of NbZr and ZrSi addition to TiCN coatings are studied, aiming for their use as protective layers for parts subjected to severe corrosion and wear. The coatings with C/N ratios ranging from 0.4 to 2.5 were deposited using the cathodic arc technique in a mixture of N 2 and CH 4 gases, on 316 stainless steel discs and Si (111) wafers. All the coatings exhibited residual compressive stresses, with values ranging from approximately-2.4 GPa to −3.5 GPa. The addition of Si led to an increase in hardness, regardless of the C/N ratio. All coatings with high C/N ratio (~2.5) presented slightly lower stress values and superior performance in 3.5% NaCl corrosive solutions, the best performance being obtained for the TiSiZrCN coating, which exhibited the highest protective efficiency to corrosion (97.8%), due to its low corrosion current density (1.734 μA/cm2) and high polarization resistance (31.775 kΩ). The tribological tests, performed at 23 °C and 250 °C, indicated that abrasion and oxidation were the predominant wear mechanism for all coatings. At 23 °C, the friction coefficients of the coated specimens were significantly lower than those of the uncoated samples. When the collective performance across all of the experimental parameters was assessed, the coatings with C/N of about 2.5 proved to be the most suitable candidates to be used in severe service conditions. • NbZr and ZrSi addition to TiCN coatings were deposited by cathodic arc. • The coatings with C/N ratios ranged from 0.4 to 2.5 were deposited. • The coatings with C/ N = 2.5 demonstrated the best performance in the 3.5% NaCl. • The coatings with C/N of 2.5 have the best wear rate at 250 °C. • Friction for the coatings is >3 times lower than those of uncoated substrate. [ABSTRACT FROM AUTHOR]

The work was devoted to the study of the effectiveness of the application of multi-component coatings, TiN–Al/TiN, TiN–AlTiN/SiN, and CrTiN–AlTiN–AlTiCrN/SiN, obtained by cathodic arc deposition to increase the wear resistance of 6WH10F carbide end mills in trochoidal milling of titanium alloy. The surface morphology of the tool with coatings was studied using scanning electron microscopy, and surface roughness texture was estimated. Microhardness and elastic modulus of the coated carbide tool surface layer were determined by nanoindentation. The process of sticking titanium to the working surface of the tool and quantitative evaluation of end mill wear with multi-component coatings at the trochoidal strategy of milling titanium alloy was studied. The CrTiN–AlTiN–AlTiCrN/SiN coating showed the maximum value of the plasticity index at the level of 0.12. The maximum effect of reducing the wear rate was achieved when using a tool with a CrTiN –AlTiN–AlTiCrN/SiN coating when the operating time to failure of end mills was increased by 4.6 times compared to samples without coating, by 1.4 times compared with TiN–Al/TiN coating and 1.15 times compared with TiN–AlTiN/SiN coating.

Laser induced breakdown spectroscopy (LIBS) was employed to find the depth profile of W‐coated CuCrZr alloy. Cathodic arc deposition method was applied to produce tungsten coating on the CuCrZr alloy. The LIBS measurements were carried out by using a Nd:YAG laser at its fundamental wavelength (1064 nm) with various fluences. The spectral intensity emitted from laser induced plasma of the coating material was investigated for both elemental and depth‐profile analyses in terms of linear correlation coefficient. Other surface characterization techniques (scanning electron microscopy and energy dispersive X‐ray) were also used to determine morphology and elemental composition. It is observed that nonuniform radial energy distribution of Gaussian laser beam caused gradual decay of spectral lines of the coating and rise of substrate lines. The results indicate that the spectral intensity from W coating was higher than that from the bulk material at same laser fluence. The high‐resolution in‐depth profile was achieved at low fluence. This study demonstrates that LIBS is a promising technique for the depth‐profiling analysis of W coating of EAST‐like material and can be used to determine the material erosion and impurity deposition on plasma facing components. [ABSTRACT FROM AUTHOR]

Abstract This work studies the surface characteristics and, particularly, the rolling contact fatigue (RCF) behavior of austempered ductile iron (ADI) samples coated with TiN based coatings of about 1 μm in thickness. Films synthesized by cathodic arc deposition (CAD) at a fixed nitrogen flow, compositional gradient films synthesized by CAD at a variable nitrogen flow and plasma based ion implanted and deposited (PBIID) films were comparatively analyzed. The results indicated that CAD films showed a strong TiN (111) preferred orientation while PBIID films a more randomly orientation. The crystallite size of CAD films was more than the double of PBIID films. Residual stresses of the PBIID films were lower than those of CAD films, the lowest hardness and elastic modulus were obtained for CAD films grown at variable nitrogen flow, while no significant differences in roughness, H/E ratio and adhesion were observed among the different films. Regarding RCF tests, failures in samples coated with TiN at constant flow were characterized by a progressive coating delamination followed by the formation of fatigue spalls inside the delaminated areas. Failures in samples coated with PBIID and gradient TiN were characterized by the formation of fatigue spalls with slight coating delamination. There were no significant differences between the RCF resistance of uncoated ADI and the samples with CAD films while the samples with PBIID films had a noticeably higher resistance. The better performance could be associated with the low compressive residual stresses and the fine grained microstructure induced by the PBIID process. Highlights • Cathodic arc deposited (CAD) films synthesized at variable and constant nitrogen flows. • Constant-flow CAD films delaminated during rolling contact fatigue (RCF) tests. • Neither variable-flow CAD nor ion-implanted/deposited films delaminated during RCF tests. • RCF behavior of austempered ductile iron was not modified by CAD. • RCF endurance of austempered ductile iron increased by ion-implanted/deposited films. [ABSTRACT FROM AUTHOR]

For the past few decades, cathodic arc-grown erosion-resistant coatings have become very popular and are widely used in aerospace applications to significantly enhance the service life of compressor blades. Though the coatings improve life, the concentrations of defects and stressed areas on the surface dictate the end life of the component. Therefore, in the present study, an attempt was made to minimize the defect area fraction along with the residual stresses in cylindrical cathodic arc-grown mono- and multilayer TiN coatings by optimizing pulsed bias voltage parameters such as duty cycle and magnitude of bias voltage. The effect of pulsed biasing and coating configuration on the physical, mechanical, and erosion properties of the TiN coatings was studied systematically. Within the monolayer TiN coating, the samples grown at −500 V pulsed bias and 40% duty cycle had the best properties with about 50% enhancement in erosion resistance. These coatings were also found to exhibit the lowest residual stress, good adhesion, and moderately higher hardness. Further, the TiN coatings grown in a multilayer configuration (TiNE-450/TiNE-350) had the best erosion resistance. [ABSTRACT FROM AUTHOR]

This article presents a study of the influence of the bias voltage and CH4/N2 gas ratio on the structure and mechanical properties of TiCN coatings. The coatings are deposited by cathodic arc deposition technology from Ti cathodes under an atmosphere of a mixture of CH4 and N2 gasses. XRD analysis shows that an increase in the methane flow changes the preferential orientation of the coating from (111) to (200) and results in a refinement of the structure (grain size reduction from 23 to 7 nm). SEM analysis shows that the coatings are stoichiometric. It was demonstrated that the bias voltage has an influence on the grain size, hardness and elasticity module. The highest hardness value of 52.5 GPa was measured at the coatings lacking a clear preferential orientation. The adhesion of the coatings showed a critical load in the range of 29-64 N. [ABSTRACT FROM AUTHOR]

It is known that cathodic arc deposition (CAD) has been widely used in industry for high quality thin film coatings. An extremely high current density (~10 12  A/m 2 ) was created to evaporate and ionize the target material rapidly. However, the CAD also produces macroparticles or droplets along with the deposition process leading to the degradation of the film properties. Magnetic filters with different designs were therefore adopted to reduce the macro particles or droplets. However, the macroparticles still cannot be fully eliminated. Lately, a newly developed PVD process known as high power impulse magnetron sputtering (HiPIMS) was found to have the capability of yielding highly ionized flux of both gas and sputtered materials by applying a high power in short pulses to the target. High plasma density in the order of 10 17 to 10 19  m −3 , which is three orders of magnitude higher than that of the conventional dc magnetron sputter (dcMS), can therefore be achieved from the large fluxes of energetic ions in a HiPIMS process. As a result, a smoother and denser thin film with better adhesion to the substrate can be obtained, leading to enhanced mechanical, electrical, and optical properties. However, it was also found the deposition rate of the HiPIMS process was much slower than that of the conventional dcMS and CAD process. Therefore, a hybridized deposition system combining CAD and HiPIMS was studied in this paper. Titanium nitride (TiN) films were deposited to investigate their microstructures, physical, chemical, and mechanical properties. The macroparticles were reduced in the HiPIMS system while thin films with enhanced hardness was obtained in the CAD system. [ABSTRACT FROM AUTHOR]

Using first principles calculations and experimental methods we show that B1 structured solid solution Ti x Nb y Al z N can be grown. The mixing free energy surface indicates that the alloys should decompose. Theoretical analysis of the thermodynamic driving force towards the spinodal decomposition shows that the force can be different in alloys with equally low thermodynamic stability but different Nb content, indicating that the detailed picture of the decomposition should also be different. Electron microscopy and nanoindentation underlines different age hardening of the samples. We demonstrate that an alloy with the optimized composition, Ti 0.42 Nb 0.17 Al 0.41 N combines high thermal stability and age hardening behavior. [ABSTRACT FROM AUTHOR]

Stainless steel and chromium-electroplated metal can change their metallic surface aspects into different colours by thin film deposition technologies. In this study, the colour change of titanium carbonitride (TiCxNy) thin films as a function of N2 and CH4 flow rates in the deposition process was investigated. TiCxNy thin films were deposited by cathodic arc in an industrial equipment at low temperature (125°C) for decorative purposes. The samples were analysed by X-ray diffraction, scanning electron microscopy, glow discharge optical emissions spectroscopy, nanohardness, nanoscratch test and colorimetric analysis. The colour slightly changes from yellow gold to light bronze with carbon addition in the thin film structure. Scratch test determines an increase of the critical load for both plastic deformation and delamination as the carbon content increases. The failure mode shifts from brittle/ductile mode to ductile mode with the increase of the carbon content. [ABSTRACT FROM AUTHOR]

The effect of the substrate temperature in the deposition process of the NiCrAl coating was evaluated on the steel substrate using cathodic arc deposition. The deposition process was conducted at temperatures of 250–700 °C. The coating microstructure properties were studied by scanning electron microscope and the coating phases were characterized by X-ray diffraction analysis for the deposited samples at different temperatures. By increasing the substrate temperature from 250 °C to 700 °C, the coating porosity was reduced from 4.4% to 0.6%. The phase studies showed that the sample deposited at the temperature of 250 °C contained the α-Cr phase and the preferred texture in this phase belonged to the (200) plane. By increasing the substrate temperature, the Cr atoms were dissolved in the γ-Ni phase and the α-Cr phase was not formed in the coating. Comparing the intensity of peaks in the X-ray diffraction analysis for the deposited samples at different temperatures showed that by increasing the substrate temperature, the crystallization degree of the coating was increased. [ABSTRACT FROM AUTHOR]

Bilayer Ti/TiN and TiAl/TiAlN coatings were deposited onto austempered ductile iron (ADI) substrates by cathodic arc deposition in an industrial device. Structure and mechanical properties of the coated samples were comparatively examined. Wear behavior of the coated samples was investigated in comparison with uncoated ADI by means of rolling contact fatigue (RCF) tests, performed in a flat washer type testing rig and using lubricated pure rolling conditions. RCF tests results were analyzed using the two-parameter Weibull distribution and the Weibayes method. The results indicate that TiN and TiAlN coatings grew with a cubic-NaCl type structure. The arithmetic average roughness of the coated samples is similar for both coating variants. The surface hardness and residual stresses are higher for the TiAl/TiAlN coated samples. The coating hardness and elastic modulus are also higher for TiAl/TIAlN. The critical loads at massive delamination and the evolution of the friction coefficients are quite similar for both coating variants. Regarding RCF, failures in coated samples were characterized by substrate spalling. No massive delamination was observed in Ti/TiN and TiAl/TiAlN coatings. The statistical analysis indicates that the deposition of Ti/TiN improves noticeably the RCF resistance of ADI while the deposition of TiAl/TiAlN does not produce significant changes. The properties mismatch between substrate and coating seems to play an important role in the RCF behavior of coated samples, since Ti/TiN coatings possess a lower mismatch with respect to ADI substrates as compared to TiAl/TiAlN. [ABSTRACT FROM AUTHOR]

AlSiN coatings were prepared by the cathodic arc deposition method at a temperature of 400 °C and pressure of 2.6 Pa. The chemical composition, determined by SEM/EDS analysis, shows that the AlSiN coating presented here has a stoichiometry structure (Al 40 Si 9 N 51 ). XPS and XRD analyses indicated AlN in both cubic and hexagonal modifications in the coating, and that the coating has a not fully completed nanocomposite structure. Nanoindentation measurements indicate nanohardness and elastic modulus of 39 GPa and 389 GPa, respectively. The coating has a very good adhesion strength with an average critical load of 28.3N (first cohesive failure) and 62.3N (first adhesion failure). The estimated wear rate and coefficient of friction of the coating are 27.2 × 10 −6 mm 3 N −1 m −1 and 0.7, respectively (using the friction pair AlSiN/Al 2 O 3 ). [ABSTRACT FROM AUTHOR]

There are demands to form nanolayered coating consisting of different materials in order to enhance the coating mechanical properties. However, poor structure control may lead to the formation of second phase and various defects. In this work, we endeavored to use cathodic arc deposition (CAD) method to fabricate TiN/Ti X Al 1 − X N nanolayered coatings with periods (Λ) ranging from 8 to 45 nm, which has great influences on coating microstructures and properties. X-ray diffraction (XRD), electron microscopy, nanoindentation and tribometry were employed to correlate coating microstructure and Λ with mechanical properties and wear resistance. The nanolayered coatings consisted of columnar grains with [111] texture, where individual grains contained low-angle grain boundaries without voids and amorphous phases. As Λ decreased, superlattices were generated, and reducing Λ from 45 nm to 13 nm yielded coatings with superior mechanical properties. The hardness peaked at 38.9 ± 3.6 GPa with a Young's modulus at 502.5 ± 40.4 GPa at 13 nm, however, when the Λ decreased to 8 nm the hardness and the Young's modulus deteriorated. It was concluded that wear resistance improved as the Λ decreased due to the greater interface population that impedes crack propagation. [ABSTRACT FROM AUTHOR]

This work studies the rolling contact fatigue (RCF) behavior of austempered ductile iron samples coated with Ti/TiN by cathodic arc deposition. The influence of the TiN layer thickness on the characteristics and RCF life of the coated samples is analyzed. RCF tests were performed in a flat washer type testing rig, using a thrust ball bearing as a counterpart. The maximum contact pressure was 1400 MPa. RCF tests results were analyzed using the two-parameter Weibull distribution. The rolling track of the tested samples was examined by using SEM and EDS. The results show that the surface hardness, residual stresses and coating adhesion strength of the samples increase as TiN layer thickness increases while surface roughness, coating hardness and elastic modulus do not vary significantly with the TiN layer thickness. Regarding the RCF tests, two failure mechanisms were observed in the coated samples, coating delamination and substrate spalling. Coating delamination turned out to be the most predominant mechanism and occurred at fewer loading cycles than substrate spalling. The EDS analysis revealed that inside the delaminated areas the Ti interlayer remained adhered to the substrates in all the cases. Extended tests on delaminated samples show growing delamination until final failure by substrate spalling occurred. The Weibull analysis indicates that the RCF life of the coated samples seems to have a tendency to increase with the TiN layer thickness and, in the case of the thicker TiN layer, to exceed the life of uncoated ADI after the extended tests. However, due to the number of samples employed, the statistic analysis does not show significant differences in the RCF behavior of the uncoated and coated samples. [ABSTRACT FROM AUTHOR]