Cathodic Arc Evaporation Research Articles

The impact of mechanical post-treatment on the tribological and corrosion behavior of CrN/CrAlN coatings applied using the CAE-PVD technique

This study examined how wet microblasting affects the tribological and electrochemical properties of CrN/CrAlN nanolayered coatings. The coatings were applied to 430 stainless steel substrates using cathodic arc evaporation (CAE), a physical vapor deposition (PVD) technique. The microblasting was performed at three different pressures (2, 4, and 6 bar) after the deposition process. Field emission SEM and X-ray diffraction techniques were employed to characterize the microstructure and morphology of the samples. The nanoscale indentation method was utilized to evaluate the indentation properties of the coatings. The tribological properties of the samples were investigated by means of a ball-on-disk tester. The coatings’ corrosion behavior was tested by EIS and PDP in a NaCl solution (3.5 wt.%). The wear results indicated that the friction coefficient decreased from 0.3 for the non-treated coating to 0.27, 0.23, and 0.5 for the coatings microblasted at 2, 4, and 6 bar, respectively. The wear resistance increased by 10 % and 23 % for the coatings microblasted at 2 and 4 bar due to the higher compressive residual stress and resistance against plastic deformation (H/E value). The EIS results revealed that the coating microblasted at 2 bar had the highest RP (2425 × 103 W cm2) and the lowest corrosion rate after 24 h of immersion in a 3.5 wt.% salt solution. The results showed that the corrosion resistance at 2 bar pressure improved approximately 16 times. The Potentiodynamic polarization (PDP) diagrams also showed that the coating microblasted at 2 bar had the lowest current density (6.3 nA cm2), indicating the highest corrosion resistance. Therefore, the optimal microblasting pressure for tribological and electrochemical applications was 4 and 2 bar, respectively.

Investigation of Ion Release and Antibacterial Properties of TiN-Cu-Nanocoated Nitinol Archwires

Background: The use of nitinol (NiTi) archwires in orthodontic treatment has increased significantly due to unique mechanical properties. The greatest obstacle for safe orthodontic treatment is chemically or microbiologically induced corrosion, resulting in nickel (Ni) release. The aim of this investigation was to enhance corrosion resistance and introduce antibacterial properties to NiTi archwires by coating them with copper (Cu) doper titanium nitride (TiN-Cu). Methods: NiTi archwires were coated with TiN-Cu using cathodic arc evaporation (CAE) and direct current magnetron sputtering (DC-MS). The morphology of the sample was analyzed via field emission scanning electron microscopy (FESEM) and chemical composition was assessed using energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transformed infrared spectroscopy (FTIR). Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to estimate the ion release. The biocompatibility of samples was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Antibacterial activity was tested against Streptococcus mutans and Streptococcus mitis. Results: Physicochemical characterization revealed well-designed coatings with the presence of TiN phase with incorporated Cu. TiN-Cu-nanocoated archwires showed a statistically lower Ni release (p < 0.05). Relative cell viability was the highest in 28-day eluates of TiN-Cu-nanocoated archwires (p < 0.05). The most remarkable decrease in Streptococcus mitis concentrations was observed in the case of TiN-Cu-coated archwires (p < 0.05). Conclusion: Taking into account biocompatibility and antibacterial tests, TiN-Cu-nanocoated archwires may be considered as a good candidate for further clinical investigations.

Mechanical, antibacterial and cytotoxic characteristics of nanolayered TiNb–Zr–Ta and nitrogen-doped TiNb–Zr–Ta coatings

Titanium and titanium alloy materials are often made as medical implants. Surface properties of titanium medical implants play decisive roles for antibacterial and biological response and tissue biocompatibility. In this study, cathode arc evaporation (CAE) technology was used to deposit TiNb–Zr–Ta and nitrogen-doped TiNb–Zr–Ta coatings with nanostructures on the Ti–6Al–4V dental abutment screws. The deposited coatings were then oxidized at high temperature to produce different oxides on the surface of the coatings. The mechanical properties, antibacterial properties and biocompatibilities of the coatings were analyzed. The effect of coatings on the abutment screw loosening and removal torque between the abutment screw and the pure titanium implant fixture was studied by removal torque measurement. In addition, Staphylococcus aureus (S. aureus) was used for evaluating the antibacterial properties of coatings, and mouse fibroblasts (L929) were used for ISO 10993-5 cytotoxicity analyses to determine whether it had good biocompatibility.Nanolayered structures and multiphases of polycrystalline TiNb–Zr–Ta were obtained by co-deposition of Ta, Zr and TiNb. When small content of N was introduced, the TiNb–Zr–Ta(N) showed a polycrystalline TiNb–Zr–Ta where N atoms entered the metallic lattice at interstitial sites. After oxidation, oxide phases of Ta2O5, TiO2, Nb2O5 and ZrO2 were formed on the surface of TiNb–Zr–Ta and TiNb–Zr–Ta(N). Ta2O5 was obtained on the surface of the coating prior to other oxides such as TiO2, Nb2O5 and ZrO2. The deposited TiNb–Zr–Ta and TiNb–Zr–Ta(N) coatings had high contact angle and exhibited a hydrophobic feature, while the annealed TiNb–Zr–Ta–O and TiNb–Zr–Ta(N)–O showed hydrophilicity. The deposited TiNb–Zr–Ta had similar hardness and Young's modulus values to that of the uncoated Ti–6Al–4V. When N was doped, the TiNb–Zr–Ta(N) had the highest hardness and Young's modulus. The hardness of the annealed TiNb–Zr–Ta(N) coating only decreased slightly due to the small oxide layer of ∼140 nm. Compared with the uncoated Ti–6Al–4V, TiNb–Zr–Ta serial coatings deposited on abutment screws had higher removal torques, which prevented the abutment screw of dental implant from loosening after long-term use. The biocompatibility of TiNb–Zr–Ta serial coatings was similar to that of the uncoated Ti–6Al–4V. In addition, the oxidized TiNb–Zr–Ta and TiNb–Zr–Ta(N) coatings had excellent antibacterial properties. It is speculated that the resulting Ta2O5 of both coatings may inhibit bacterial growth and improve the antibacterial effect. Based on the above advantages, the TiNb–Zr–Ta serial coatings are expected to have the potential to be applied to biomedical implants.

The influence of corrosive medium on the selected tribological properties of ZrSi-based nitride and oxynitride deposited on 316L stainless steel

Targeting to restore the function of load-bearing joints which are subjected to high levels of friction and wear during the normal activity, the aim of the current study was to assess the extent of the role played by the corrosive environment on the underlaying tribological mechanism. In this study we deposited by reactive cathodic arc evaporation technique ∼ 1 μm thick, stoichiometric ZrSi-based nitrides and oxynitrides coatings, either as monolayer or double-layer structure on 316L steel substrates. Tribological tests were conducted in dry and two commonly used corrosive environments: Ringer and 0.9 % NaCl solutions. We demonstrate that the ZrSiN and ZrSi(N,O) coatings improved the wear performance of 316L stainless steel in biological environments, reaching even ∼ 94 % improvement as compared with the bare substrate for the ZrSi(N,O) coating.

Effect of Nitrogen Pressure and Substrate Bias Voltage on Structure and Mechanical Properties of Vacuum Arc Deposited VN Coatings

The binary vanadium–nitrogen (V–N) coatings were formed using cathodic arc evaporation. Two sets of coatings were produced using: (a) nitrogen pressure (pN2) from 0.001 Pa to 3 Pa at a constant substrate bias voltage (UB) of − 100 V and (b) a substrate bias voltage from − 50 to − 300 V at a constant nitrogen pressure of 1.5 Pa. The influence of the above parameters on the coating properties, in particular on the insufficiently investigated and described adhesion of the coatings to the substrate, was demonstrated. The phase transformation V → V + V2N → V + c-VN → h-VN → h-VN + c-VN and c-VN → h-VN occurs for coatings formed with increasing nitrogen pressure and substrate bias voltage, respectively. With the increase in pN2 and UB, an increase in coating hardness and adhesion to the substrate is observed, as well as an improvement in wear resistance.

The effect of substrate bias voltage on the mechanical and electrochemical corrosion properties of multilayered CrN/CrAlN coatings produced by cathodic arc evaporation

AbstractThe multilayered CrN/CrAlN film was deposited on the SS420 substrate by cathodic arc evaporation technique. The effect of substrate bias voltage was investigated on the microstructure, surface morphology, and mechanical and electrochemical corrosion properties of the deposited film. The deposited CrN/CrAlN coatings were characterized by X‐ray diffraction and field emission scanning electron microscope techniques. Mechanical properties, corrosion resistance, and surface morphology of the coated samples were studied by nano‐indentation, polarization test, electrochemical impedance spectroscopy, and atomic force microscopy, respectively. Adhesive and dense nanostructure CrN and CrAlN phases were successfully deposited on the substrate. The refinement of the coating crystallite was observed from 31.2 to 24.3 nm by increasing the substrate bias voltage, this improved the mechanical properties of the coating. The number of macroparticles, pinholes and porosities, and the surface roughness of coatings significantly decreased by increasing the substrate bias voltage. The CrN/CrAlN coating reduced the corrosion current density in contrast to the SS420 substrate. Better corrosion resistance was obtained for the coating deposited at 150 V of bias voltage due to lower defects in the film structure.

Characterization of (AlCrTiVZr)N High-Entropy Coating Produced by Cathodic Arc Evaporation

Characterization of (AlCrTiVZr)N High-Entropy Coating Produced by Cathodic Arc Evaporation

Whether macro-droplets generate or develop in depositing hard coatings by cathodic arc evaporation technique

The deposition of hard coatings of different materials on low-performance tools, intricate parts, and low-cost or less favorable materials is a topic of great worth. This study discusses the deposition of titanium nitride coatings on high-speed steel discs by employing the cathodic arc evaporation technique. Before the deposition of titanium nitride coating, a titanium layer is deposited on the substrate to enhance adhesion between the substrate and coating. In one experiment, the titanium nitride coating deposits without the titanium interlayer. When there is no deposition of the titanium interlayer at the start of the process, the developing different-sized droplets or particles are lower. When there is a deposition of the titanium interlayer first for 8 and 16 min, there are also droplets. In the published literature, the investigated hard coatings suggest generating different-sized droplets. However, such concepts cause hurdles in coating technology advances and reducing droplets. The study has a pronounced effect on scientific and industrial research in different areas. The study aims to investigate whether the droplets develop or they generate. From the application of some well-known characterization techniques, the discussed results confirm the development of droplets in the deposited hard coating rather than the generating.

Dry machining characteristics of coated inserts and multi response optimization through DEAR‐Taguchi method

AbstractThe primary intent of the proposed research work is to investigate the effectiveness of the titanium aluminium nitride/tungsten carbide‐carbide coated insert during dry turning structural stainless steel. The aim of the study is to simultaneously optimise machining variables like spindle speed, depth of cut and feed for several responses like flank wear, material removal rate and surface roughness. Titanium aluminium nitride/tungsten carbide‐carbide is coated on the surface of carbide tool by cathodic arc evaporation method. The characterization studies have been conducted to ensure the existence of coating material. Micro hardness of coated and pure inserts was tested, which confirms that titanium aluminium nitride/tungsten carbide‐carbide coated insert possesses 17.43 % augmented hardness over pure inserts. The machining was performed by adopting Taguchi experimental design. A multi‐response optimization approach was applied in this study that included ranking methodology based on data development analysis and Taguchi's design. The performance index for multiple responses was measured and mathematically analysed for their effect on processing parameters. The combination of parameter such as spindle speed: 2000 min−1; cutting depth: 0.45 mm and feed rate: 0.16 mm rev−1 was experimental as optimal machining parameters.

The Effect of Negative Bias Voltage on the Microstructure and Hot Corrosion Behavior of Heat-treated NiCoCrAlY Coatings Applied Via the Cathodic Arc Evaporation Physical Vapor Deposition Method

The Effect of Negative Bias Voltage on the Microstructure and Hot Corrosion Behavior of Heat-treated NiCoCrAlY Coatings Applied Via the Cathodic Arc Evaporation Physical Vapor Deposition Method

Microstructure, mechanical properties and optical reflectance of TiNiN films deposited on silicon substrates using cathodic arc evaporation

Variations in applied substrate bias during cathodic arc deposition may impose intriguing consequences on the mechanical and optical properties of TiNiN coatings. Here, TiNiN films were fabricated onto Si substrates using a Ti95Ni5 (at.%) alloy target via cathodic arc evaporation employing a range of substrate bias voltages varying from 0 to -150 V. The aim of this study was to investigate the microstructures, mechanical performance, and optical properties of the TiNiN films in terms of the employed substrate potential. A significant enhancement (57%) in hardness for the TiNiN film was attained at -50 V as compared to zero substrate potential. This was principally attributed to the evolution of a fine, equiaxed nanocomposite structure, in association with the induction of a very high compressive residual stress at -50 V. In contrast, a maximum optical reflectance of 73% in the near-infrared range was determined for the coating synthesised at -150 V. It is speculated that incidence of fewer macroparticles on the film surface at elevated negative potentials, due to the induction of a higher repulsive force, may reduce the scattering of light incident on the coating's surface, promoting improved spectral reflectivity.

The post‐annealing effect on tribological and corrosion behaviors of CrN/AlCrN multilayered coating applied by CAE‐PVD

AbstractThe present study investigated the wear and electrochemical behaviors of CrN/AlCrN multilayered coatings post‐annealed at 300, 450, and 600°C temperatures. The cathodic arc evaporation technique has been utilized to deposit the coatings. Scanning electron microscope, field emission SEM, energy‐dispersive X‐ray, grazing incidence X‐ray diffraction, and Rockwell‐C indenter methods were used to characterize the coatings and to investigate the interdiffusion between the multilayered CrN/AlCrN and the H13 base metal. The results showed that the sharp interface of the CrN and AlCrN layers was blurred by the annealing process supporting the interdiffusion of the layers. The reciprocating wear test and the microhardness tester were used to evaluate the coatings’ mechanical behavior. The hardness and roughness of the coatings were increased by increasing the post‐annealing temperature. The smallest wear rates were observed for the samples treated at 300 and 450°C, which were approximately 17 times and 12 times smaller than the wear rate of the sample annealed at 600°C. Electrochemical testing was used to study the corrosion behavior of the coatings. The results showed that by increasing annealing temperature, corrosion resistances of the coatings are improved. As a result, the corrosion current density of the 600°C annealed coating was approximately 434 times smaller than as‐deposited coatings.

Effect of plasma nitriding substrate current density on the adhesion strength of in situ PVD TiN coatings

TiN coatings were in situ deposited on un-nitrided and nitrided M2 high speed steels by electrically enhanced cathodic arc evaporation technology. The morphology, microstructure, phase composition, as well as microhardness and nano-hardness of the samples were analyzed by scanning electron microscope, optical microscope, X-ray diffraction, Vickers hardness tester, and nano-indentation, respectively. In especially, the effect of nitriding substrate current density on the adhesion strength of in situ TiN coatings was investigated by Rockwell indentation and scratch tests. The results showed that the nitrided layer thickness increased with increasing substrate current density and “bright” nitrided layer was achieved. In the Rockwell indentation test, the radial cracks on the surface of the duplex-treated samples originated from the hard and brittle nitrided layer as compared to the nitrided substrate, which corresponded to the failure mechanism of brittle fracture. In the scratch test, the adhesion strength of coating to substrates was significantly improved by nitriding pretreatment. Furthermore, the critical load of the duplex-treated samples increased with the increase of nitriding substrate current density. In addition, tensile cracks only occurred in the case of the N120/TiN sample.

Microstructure evolution and mechanical performance of tetrahedral amorphous carbon coatings with dense droplets during annealing

Tetrahedral amorphous carbon (ta-C) coatings with approximately 50% sp3C were deposited onto cemented carbide alloy YG6 and Si wafers via direct vacuum cathode arc (DVCA) evaporation at different substrates temperatures. Coated specimens were annealed in a 5 Pa argon atmosphere. The micromorphology and chemical bonding structure of these coatings with different treatments were characterized using field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The mechanical performance was tested using a nanoindenter and film stress instrument. The obtained ta-C coatings contained dense droplets of various sizes (“abnormal particles” (An-Ps)). The densities of the An-Ps were controlled by the graphite cathode target arc rather than the substrate temperature, and their ID/IG ratios were close to their counterpart coating matrix. Increasing the substrate temperature was beneficial for increasing the sp2C fraction and the number of aromatic ring sp2C sites. Growth, coalescence, and leveling-diffusion of aggregates in the coating matrix and An-Ps occurred during annealing, which was related to the existing state of the sp2C sites, including the olefinic chain and aromatic ring. The residual stress variation with annealing temperature also depended on the sp2C state. The residual stress in the coating increased during annealing when the number of aromatic ring sp2C sites exceeded a certain critical value.

Enhancement of discharge and mechanical properties of ta-C films by pulse-enhanced cathodic arc deposition

A home-made straight-duct filter cathodic vacuum arc system was used to synthesize tetrahedral amorphous carbon (ta-C) films. The ta-C films were fabricated using both direct-current cathodic arc evaporation (DC-CAE) and pulse-enhanced cathodic arc evaporation. A series of films were prepared as a function of pulse current ranging from 500 to 1000 A compared with 80 A direct current. The introduction of pulse current could markedly increase instantaneous input power (Wiip). The pulse-enhanced Wiip led to the increase in average substrate current from 0.46 to 1.07 A. Moreover, compared with DC-CAE, the pulse current of 1000 A significantly increased the intensity ratios of C II/(C I + C II) and C II/Ar II by about 65% and 130%, respectively. All the results showed that the pulse-enhanced Wiip substantially improved the evaporation and ionization rate of graphite. However, due to thermal-induced graphitization conversion, the threshold pulse current was 800 A. Under this pulse current, the film exhibited the smallest ID/IG (0.26) as well as the highest sp3 fraction (64.3%). Correspondingly, the highest hardness (≈40 GPa) and the preferable toughness (H/E* of 0.12 and H3/E*2 of 0.52) were simultaneously achieved.

MORPHOLOGY AND SPUTTERING OF TUNGSTEN NITRIDES COATINGS EXPOSED TO DEUTERIUM PLASMA

Processes of sputtering, surface modification and change in the stoichiometric composition of W and WN coatings deposited on stainless steel by cathodic arc evaporation were studied under the influence of low-energy (500 eV/D) deuterium plasma with fluence of (1…4.5)1024 D2 +/m2 at room temperature. The composition of the WN coating changes under the influence of deuterium plasma, its enrichment with tungsten up to 100 % is observed. Results of erosion studies indicated that the sputtering yields for coatings WN and W are ~ 2.410-2 at./ion and to be systematically higher than the published data which were measured for bulk materials.

Microstructure, Mechanical Properties, Wear and Erosion Performance of a Novel High Entropy Nitride (AlCrTiMoV)N Coating Produced by Cathodic Arc Evaporation

(AlCrTiMoV)N high entropy nitride film was prepared on 17-4PH stainless steel substrate using cathodic arc evaporation (CAE). The composition, microstructure, and thermal stability were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Mechanical properties such as hardness and Young’s modulus and coating performance against wear and erosion were also evaluated. The results show that the (AlCrTiMoV)N coating assumes a single-phased solid solution B1 FCC structure. It has excellent thermal stability and retains its structure with no decomposition observed up to a temperature of 1000 °C. The hardness and elastic modulus are measured as 21.3 GPa and 304 GPa, respectively. The coating contains some metallic droplets. As a potential protective coating, the (AlCrTiMoV)N coating has a lower wear rate but a higher erosion rate when compared to the TiN baseline coating.

Tribological Properties and Cutting Performance of AlTiN Coatings with Various Geometric Structures

The development of advanced machining techniques requires high-performance tool coatings. To improve the wear resistance and cutting performance of AlTiN coatings, a structure optimization strategy involving bias control and a nano-multilayer architecture strategy is presented. The investigated AlTiN coatings were deposited by cathodic arc evaporation and studied with regard to phase structure, hardness, adhesion, and tribological properties by a combination of X-ray diffraction, nanoindentation, scratch, and ball-on-disk friction tests. A high bias potential (up to −120 V) with enhanced adatom mobility suppressed the formation of the wurtzite structure AlN in AlTiN. In addition, the epitaxial growth of Al0.67Ti0.33N on Al0.5Ti0.5N in the AlTiN nano-multilayer could also promote the single-phase structure. The hardness of AlTiN-based coatings with a dominated cubic structure was 3–4 GPa higher than conventional ones. In addition, the interlayer interfaces in the Al0.67Ti0.33N/Al0.5Ti0.5N multilayer could deflect the cracks and thus improve the fracture toughness. As a consequence, the Al0.67Ti0.33N/Al0.5Ti0.5N multilayer with enhanced mechanical properties obtained the lowest wear rate of 1.1 × 10−5 mm3/N·m and the longest cutting lifetime of 25 min during dry turning the SUS304 stainless steel.

Parameters study of carbon bombardment step for enhanced adhesion of thick DLC coating deposited by cathodic arc evaporation

The main limitation for the deposition of thick (> 5 μm) DLC coatings is to achieve adhesion to the substrate. In the present work, the adhesion of thick (~20 μm) amorphous carbon coatings was analyzed considering the combination of metallic chromium as bond layer and a carbon bombardment step before the deposition of the functional coating. The carbon bombardment step was included to generate an interfacial structure composed by a mixing layer of Cr and C and a carbon transition layer rich in sp2 bonds. The complete deposition process was made by cathodic arc and the substrate was nitrided steel. Different sets of parameters were used during the carbon bombardment to change the interfacial structure and to analyze the effect on adhesion. The parameters evaluated were the bias voltage, duration, cathode current and temperature. The adhesion of a-C layer was assessed by scratch tests and the interface structure was evaluated by scanning transmission electron microscopy (STEM). Results indicate that a lower bias voltage possibly increased the sp3 content of the carbon transition layer, mitigating the negative impact of a thicker carbon transition layer. Moreover, an increase in the carbon cathode current may increase the adhesion, possibly by an increase in the thickness of the mixing layer. Finally, improved adhesion was achieved when the temperature of the bombardment was reduced. A diagram of expected behavior for the adhesion (in terms of critical load during scratch tests) as a function of carbon transition layer thickness and sp-bonds was proposed based on the available results.

Microstructure, mechanical properties, and oxidation behavior of arc-evaporated Cr–Al–O–N coatings with various Cr/Al ratios

Cr–Al-based oxynitride materials have attracted significant attention as hard protective coatings for decades. However, knowledge of the influence of the constituents on oxidation behavior is limited. Here, Cr–Al–O–N coatings with various Cr/Al ratios prepared using cathodic arc evaporation were studied with respect to their microstructure, mechanical properties, and oxidation behavior. With a decrease in the Cr/Al ratio, the coatings yielded a phase evolution from face-centered cubic CrN to rock salt-type cubic (Cr, Al)2O3 to a wurtzite-type hexagonal AlN structure. The cubic structured coatings showed a comparable indentation hardness, much higher than that of the Cr-free Al–O–N coating with a wurtzite structure. Thermogravimetric together with differential scanning calorimetric (TG-DSC) analysis revealed that the ternary Cr–O–N and Al–O–N coatings were more susceptible to oxidation than the quaternary Cr–Al–O–N coatings. Moreover, isothermal oxidation experiments indicated that the addition of 66 at.% Al within the metallic species gives rise to the growth of an Al-rich oxide scale on top of the Cr–Al–O–N coating. However, this oxide scale containing substantial voids cannot prevent the underlying coating from oxidation. Oxidation kinetics study illustrates that the oxidation activation energies of (CrxAl1−x)–O–N coatings with x = 1.00, 0.76, 0.58, 0.33, and 0 are 252.3, 305.2, 370.7, 303.8, and 297.7 kJ/mol, respectively. The best oxidation resistance was obtained by the (Cr0.58Al0.42)–O–N coating, whereas the Al-containing (Cr0.33Al0.67)–O–N coating showed inferior oxidation resistance owing to its high intrinsic oxygen fraction.