Arc Evaporation Research Articles

Influence Mechanism of Metal Vapor in Plasma Arc Lap Welding

A three-dimensional coupled tungsten electrode–plasma arc–metal vapor– weld pool model was developed to investigate plasma arc and metal vapor characteristics, weld pool convection, and energy transfer in conduction plasma arc lap welding. The arc energy efficiency was also calculated. The numerical results showed that in conduction plasma arc lap welding, the constraint effects of the plasma arc by a small constricting nozzle, plasma gas, and electromagnetic force were strong, and no keyhole was formed inside the weld pool, so the heat flux on the weld pool surface was high as well as the weld pool temperature and mole fraction of Fe vapor above the weld pool surface. The high concentration of Fe vapor in the arc decreased the conduction energy from the plasma arc to the weld pool along with the arc energy efficiency. The calculated arc energy efficiency was only 50.2%. Without considering Fe vapor, the calculated weld pool had complete joint penetration. When considering Fe vapor, the calculated weld geometry agreed well with the experimental result.

Influence of the Addition of the Elements Ti and Cr on the Structure, and Mechanical and Tribological Properties of AlSiN Coatings

The influence of Al/Ti and Al/Cr ratios on the structural, mechanical and tribological properties of AlTiSiN and AlCrSiN coatings, deposited by the cathodic arc evaporation PVD method at a temperature of 400°C, was investigated. The remains of the original AlSiN hexagonal phase were observed in the obtained coatings as well as the crystallites of cubic TiN and CrN, respectively. XPS analysis assumes the presence of a substoichiometric SiN. The addition of 11 at.% Ti or 13 at.% Cr in AlSiN led to an increase in both the coating’s resistance to plastic deformation and the plasticity index. The addition of 13 at.% and 24 at.% Cr to the AlSiN coating structure resulted in a decrease in the average coefficient of friction with 18% and 36% against a counterpart of Al2O3, respectively, and with 36% for both concentration against steel ball counterpart. The addition of Ti have no influence on the values of the coefficient of friction at using ceramic counterpart, while at steel counterpart decreased it up to 30%. Both element change the abrasion effect of the coating.Keywords:AlCrSiN; AlTiSiN;Cathodic Arc Deposition; Tribological Behaviour; Abrasion Resistance; Nanoindentation

Investigation of the influence of the features of the deposition process on the structural features of microparticles in PVD coatings

The article discusses the specifics of the formation of the coating structure when the vacuum arc evaporator with controlled accelerated motion of a cathode spot of Arc-PVD (CAA-PVD) is used. The article also presents the results of the studies focused on the relationship between the shape and the crystalline structure of the microparticles formed during the coating deposition process and the spatial arrangement of a sample in the chamber of the unit. The influence of the structure of the contact zone between a microparticle and the substrate surface on the crystalline structure of a microparticle was analyzed. The conducted experiments detected the relationship between a solidified microparticle and its initial size. The studies focused on the phase composition of microparticles confirmed a hypothesis on the formation of a nitride shell around a metallic core.

Performance evaluation of HiPIMS, S3p and CAE deposited coatings during dry turning of Dss2205

The present study is an extension of our previous work. Performance evaluation of single-layer AlTiN coating deposited by Scalable Pulse Power Plasma (S3p) and High Power Impulse Magnetron Sputtering (HiPIMS), with multi-layer TiN/TiAlN and AlTiN/TiAlN coating deposited by Cathodic Arc Evaporation (CAE) is carried out. Taguchi’s full factorial design with L9 orthogonal array was used for machining. AlTiN (S3p) coating exhibited a tool life of 111 min, 1.5 times as much as AlTiN (HiPIMS) coating. Multi-layer coatings could not offer comparable performance with single-layer coatings. Among the multi-layer coatings’ tools having the top layer of Al performed better. Surface roughness exhibited by AlTiN (S3p) tool was 1.2 µm compared to 1.8 µm by AlTiN (HiPIMS) tools. The rate of reduction of cutting force for AlTiN (HiPIMS) and AlTiN (S3p) tools was found to be 5% and 11%, respectively. Multi-layer TiN/TiAlN-coated tool exhibited 2.5 times higher surface roughness compared to single-layer AlTiCrN coated tool. Empirical models showed predictability of 5% and 20% for cutting force and surface roughness respectively. The higher predictability range for surface roughness is due to influence of both cutting speed and feed. The developed models can be used for selection among AlTiN (S3p) and AlTiN (HiPIMS) coated tools.

Electrochemical and biological properties of mono- and bilayer nitride coatings deposited on Ti–6%Al–4%V alloy

Mono- and bilayer coatings were deposited by plasma nitriding process, cathodic plasma electrolytic deposition, and cathodic arc evaporation methods to improve the corrosion resistance and biological properties of the Ti–6Al–4V substrate. Coatings characterizations include phase analysis, surface morphology, and film microstructure observations were done using X-ray diffraction (XRD) analysis, atomic force microscope, and field emission scanning electron microscopy (FESEM), respectively. The results confirmed the formation of titanium nitride phases (TiN and Ti2N) in plasma nitriding and cathodic arc evaporation processes and deposition of oxy-nitride phases (TiNxOy) in plasma electrolytic nitriding process. The electrochemical study of coated and uncoated samples in a simulated body fluid (SBF) solution revealed the lower corrosion current density for bilayer nitride coating in comparison to the monolayer coating and substrate. Lower penetration of solution and more stable phases such as TiO2 improved the corrosion resistance of bilayer coatings. Hemocompatibility and MTT assay were performed on the coated and uncoated sample to determine the blood compatibility and cell viability. The statistical results showed better cell growth on the bilayer nitride coatings after three days.

Electro-spark deposition of amorphous Fe-based coatings in vacuum and in argon controlled by surface wettability

Amorphous Fe-based coatings deposited on AISI 420S steel by electro-spark deposition in argon at atmospheric pressure and in vacuum using a Fe41Co7Cr15Mo14C15B6Y2 electrode were studied. At the same pulse energy, melt droplets formed during processing in vacuum wet the substrate surface better. This is due to the in situ formation of a thin layer during arc evaporation of the electrode in vacuum prior to the melt transfer. Vacuum-deposited coatings exhibit significantly lower corrosion current and wear rates in seawater.

Evaluation of high temperature corrosion resistance of CrN, AlCrN, and TiAlN arc evaporation PVD coatings deposited on Waspaloy

During the regular operation of a petrochemical plant, the degradation and corrosion of some metallic parts frequently occur. These parts are exposed, from the oil extraction to refining processes, to an environment that includes strong acids or bases, under high pressures, and high temperatures, up to 760 °C. Waspaloy (UNS N07001) is a material currently applied to manufacture components exposed to hot corrosion. This study evaluates the high temperature corrosion behavior of CrN, AlCrN, and TiAlN coatings deposited by Arc Evaporation Physical Vapor Deposition (PVD) process onto Waspaloy base material. The AlCrN and TiAlN PVD coatings showed higher hardness, 28 GPa (TiAlN) and 33 GPa (AlCrN), and elastic modulus than the CrN coating. The AlCrN coating presented the lowest corrosion rate values, 1.35 × 10−5 mg2·cm−4·s−1, while TiAlN and CrN showed higher corrosion rate values, 1.66 × 10−5 and 2.09 × 10−4 mg2·cm−4·s−1 under 700 °C hot corrosion condition. The use of X-ray diffractograms, and Raman spectroscopy, to evaluate the coating after hot corrosion tests based on chemical composition indicated that AlCrN and TiAlN coatings formed Al2O3 and TiO2 on the surface, which was responsible for their higher corrosion resistance.

Specific features of the structure and properties of arc-PVD coatings depending on the spatial arrangement of the sample in the chamber

The paper considers the influence of the spatial arrangement of samples in the unit chamber on parameters of deposited coatings when using a vacuum arc evaporator with controlled accelerated motion of a cathode spot of Arc-PVD (CAA-PVD) compared to a standard used in NNW6.6 evaporator with magnetic cathode spot retention by axial field. The distance from a sample to the cathode surface and an offset of the sample about the central axis of the cathode were varied. The study reveals the regular patterns’ influence on the spatial sample arrangement on coating properties, such as thickness, microhardness, surface macroparticle content density, and crystal structure. Using the CAA-PVD technology allows reducing the distance from the cathode surface to the samples from 230 to 150 mm, forming a coating with a higher microhardness and lower density of microparticles than the standard used in NNW6.6 evaporator. It is found that a CAA-PVD evaporator forms a coating with a higher hardness and lower density of microparticles compared to a NNW6.6 evaporator. The application of the CAA-PVD technology significantly (by 30–270%) reduces the density of microparticles on the coating surface, and the coating is characterized by a more uniform thickness and distribution of microparticle density.

Исследование структурно-фазового состояния и механических свойств покрытий ZrCrN, полученных вакуумно-дуговым методом

Introduction. Modern technologies allow the synthesis of nanostructured coatings from multiple chemical elements to combine different physical, mechanical, and chemical properties in one coating. Promising in this respect are coatings formed via layer-by-layer deposition of zirconium and chromium nitrides. The deposition of various chemical elements on various substrates requires separate studies in order to produce high-strength and wear-resistant coatings. The purpose of this work is to study the structural-phase state and mechanical properties of ZrCrN coatings formed by plasma-assisted vacuum arc evaporation. Materials and methods. The investigation is performed on specimens comprising VK8 hard alloy substrates with zirconium and chromium nitride coatings as well as with multilayer ZrCrN coatings. The methods used are confocal laser scanning microscopy, X-ray diffraction analysis, high-resolution scanning electron microscopy, nanoindentation, and scratching. Results and discussion. The experimental results obtained showed that the mode of multilayer ZrCrN coating evaporation greatly affects the structure, morphology, surface roughness, and mechanical properties of the coatings. In particular, by varying the substrate rotation speed during coating deposition it is possible to control the deposition time of each coating layer and thereby modify the layer properties. Conclusions. The investigation results showed that variation of the evaporation conditions allows one to obtain a ZrCrN coating with a high nanohardness of 45 GPa on a VK8 alloy substrate. Analysis of mechanical test results indicate good adhesion between the studied coatings and the substrate. Scratch tests revealed that fracture of CrN and ZrN coatings occurs by the cohesive mechanism, and the surface of ZrCrN coatings exhibits uniform scratches without any signs of fracture. Based on the results obtained, ZrCrN-2…ZrCrN-4 coatings can be recommended for use as hard and wear-resistant coatings.

Comparison of electrochemical behavior of CrN single‐layer coating and Cr/CrN nanolayered coating produced by cathodic arc evaporation physical vapor deposition

AbstractThe aim of the present work is to study the CrN single‐layer coating and the Cr/CrN nanolayered coating by cathodic arc evaporation physical vapor deposition (CAE‐PVD) on AISI 304 stainless steel and to assess the electrochemical behavior of the coatings. Field emission scanning electron microscopy (FE‐SEM) and X‐ray diffraction (XRD) were utilized to study the morphology and microstructure of the coatings. The mechanical behavior of the coatings was studied by the nanoindentation technique. The electrochemical behavior of the formed coatings in 3.5 wt.% NaCl solution was investigated via electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) tests. Based on the microscopic images, it was realized that both CrN and Cr/CrN coatings were formed having a dense structure on the substrate. The results of EIS measurements showed gradual changes in the polarization resistance of the Cr/CrN nanolayered coating during the immersion time. However, significant changes in the polarization resistance of the CrN single‐layer coating were seen by increasing immersion time comparing with the Cr/CrN coating. The higher polarization resistance of the Cr/CrN coating can be attributed to the effects of the interface between the layers in comparison to the CrN coating.

Tribological properties of in-situ PVD TiAlN, TiSiN, and TiAlN/TiSiN coatings under ambient air and vacuum environment

It is known that the interest in manufacturing in a vacuum environment has increased in recent years. Thus, the wear behavior of mechanical tools under vacuum conditions has critical importance. However, adhesion and cold-welding problems between tool and working piece in vacuum conditions lead to poor wear properties and severe coefficient of friction values. Surface treatment methods such as physical vapor deposition coatings can eliminate these undesirable consequences, especially transition metal nitrides. In this study, TiAlN, TiSiN, and TiAlN/TiSiN films were coated on AISI H13 tool steels employing the cathodic arc evaporation technique. Whether the coatings grown to the substrate surface have a positive contribution to the wear performance of the substrate in the ambient air and vacuum environment was answered. Scanning electron microscope, energy dispersive spectrometer, and X-ray diffractometer analyses were used to attain structural properties. The hardness was measured using a nano-hardness tester, and the adhesion properties were determined by a scratch test. The wear behavior of the substrate and coating samples are determined under 2 N constant normal load and using WC-6%Co counter bodies under ambient air and vacuum conditions. The hardness of samples improved owing to surface coatings, and the highest nano-hardness value was determined from the TiSiN coatings as 39.42 GPa, which is ∼700% greater than the substrate. It has been observed that coated samples have superior wear performance in both wear conditions. Besides, it is determined that those tested under a vacuum condition showed superior wear resistance than the samples tested under ambient air. While TiSiN film exhibits the highest wear resistance in ambient air, the TiAlN/TiSiN layer is the best in a vacuum environment. Owing to the deposited coatings, the seizure mechanism between the friction surfaces, which is frequently encountered in the vacuum environment, is prevented, and a fascinating improvement in terms of friction coefficient is achieved.

Morphology investigation of porous carbon nanofibers

Carbon nanofibers (CNFs) have been used in many applications such as sensors, energy storage and biomedical applications owing to high electronic conductivity and chemical stability of CNFs. Performance of carbon nanofibers are influenced by the physical and chemical properties of nanofibers. Furthermore, morphology, porosity and specific surface area are important properties for several applications including energy storage and sensors. There are several techniques to produce nanofibers including chemical vapor deposition, catalytic synthesis, arc discharge and electrospinning. Controlling surface area and porosity is vital considering the performance of CNFs. In this study, polyacrylonitrile (PAN) nanofibers were produced via two commonly used nanofiber production techniques; electrospinning and centrifugal spinning. The morphology of the polymeric nanofibers was studied by using SEM. Moreover, heat treatment was applied in air and the inert atmosphere to fabricate carbon nanofibers and porous carbon nanofibers. The effect of production technique on the morphology and chemical structure was investigated via SEM and XRD studies. Electrospun PAN/PS nanofibers showed beads on string morphology due to low viscosity of the spinning solution while uniform fibers without defects were obtained by using centrifugal spinning technique. Centrifugally spun PAN nanofibers have rough surface while PAN nanofibers with smooth surface was obtained by using electrospinning technique. PCNFs derived from centrifugally spun PAN/PMMA nanofibers had rough surface with porous structure and XRD analysis proved the amorphous structure of PCNFs.

Comparative analysis of cavitation erosion of Cr-C carbide coatings depending on the carbon content

The aim of the study was to conduct a comparative analysis of the cavitation erosion resistance of thick (up to 20 μm) Cr-C coatings by means of the rotating-disk testing method. An experimental study was carried out of the process of cavitation destruction of Cr18Ni10Ti stainless steel samples with Cr-C thick coatings depending on the carbon concentration in the coating. Nanocrystalline thick coatings of Cr-C were deposited by using the cathodic arc evaporation (Arc PVD) method. The results showed that the erosion rate of the coated samples was more than four times less than that of the uncoated sample. The Cr-C samples coated with 28.8 at % carbon content demonstrated less surface damage compared to the other coated samples and the reference samples.

CO2 Utilization by Electrolytic Splitting to Carbon Nanotubes in Non‐Lithiated, Cost‐Effective, Molten Carbonate Electrolytes

AbstractCarbon nanotubes (CNTs), have extraordinarily high tensile strength, electrical and thermal conductivity, and electrical storage capabilities. To date, CNTs have had limited use due to their high synthesis cost. The synthesis costs decrease when CNTs are prepared by transition metal nucleated molten electrolytic CO2 splitting, rather than by conventional chemical vapor deposition or arc deposition techniques. In addition to cost, a second advantage of CNT electrosynthesis is that the process consumes the greenhouse gas CO2 in its transformation to CNTs (and oxygen), providing a path to climate mitigation. However, electrolytic high yield, CNT syntheses has only been demonstrated with expensive lithiated electrolytes, such as pure or mixed Li2CO3. This study demonstrates, after several hundred failures, that carbon nanomaterials, can be synthesized from CO2 in non‐lithiated electrolytes. In the new sodium barium carbonate electrolytes, lower mobility due to the absence of lithium ions is overcome by: i) low current density; or ii) the introduction of oxides, such as BaO, to induce graphene walls to facilitate passage of larger cations during the process of growing CNTs; and/or iii) addition of specific transition metal nucleation agents, such as Fe2O3. The electrolysis uses inexpensive anodes and cathodes to form carbon nanomaterials, including straight and coiled CNTs.

On the preferred orientation in Ti1–x Al x N and Ti1–x–y Al x Si y N thin films

Abstract The influence of the deposition geometry and the chemical composition on the form and degree of the preferred orientation of crystallites was investigated in TiN, Ti1–x Al x N, and Ti1–x–y Al x Si y N thin films deposited by cathodic arc evaporation. The deposition geometry was varied by changing the angle between the cathodes and the substrates. The chemical composition of the thin films was modified by the choice of the cathodic materials. In TiN thin films, the crystallites were preferentially oriented with the {111} direction perpendicular to the sample surface, independent of the deposition geometry. Besides, a well-pronounced in-plane texture was observed. Co-deposition of Ti, Al, and Si in nitrogen atmosphere stimulated inclination of the texture direction towards the sample surface, which can be described as a change of the texture direction related to the sample surface perpendicular direction, and reduced the amount of the in-plane texture in the coatings (the preferred orientation of crystallites in the plane of the coating).

Hybrid magnetron sputtering of ceramic superlattices for application in a next generation of combustion engines

A hybrid magnetron sputtering process (dcMS/HiPIMS) was developed to manufacture nanostructured CrN/Cr1-xAlxN multilayers, motivated by improving the low-emission efficiency when applied on gas-nitrided diesel piston rings of a next-generation of combustion engines. In order to improve the mechanical, tribological, and corrosion behavior of the multilayers, the hybrid dcMS/HiPIMS process was designed by selecting the optimal sputtering procedure applied to AISI 440 base steel. The effect of substrate bias and carousel rotational speed on the phase composition, crystallographic texture, residual stresses, surface roughness, coating periodicity and densification, instrumented hardness, elastic modulus, as well as wear and corrosion resistance was determined. The results have demonstrated that hybrid magnetron sputtering produces multilayers with a superlattice structure, which outperforms commercial PVD coatings of CrN for diesel piston rings manufactured by cathodic arc evaporation. Also, multilayer periodicities in the range of 5 to 10 nm yield the best tribological performance under bench tests for the piston ring/cylinder liner system.

Mechanical properties and high temperature oxidation resistance of (AlCrTiV)N coatings synthesized by cathodic arc deposition

High entropy alloy nitrides (AlCrTiV)N coatings were deposited by cathodic arc evaporation at various deposition bias and temperature. The mechanical properties of the as-deposited coatings and their oxidation resistance after annealing at various temperatures were analysed. X-ray analyses show in all coatings a FCC structure with a (111) preferred orientation up to 750 °C. Up to 600 °C, no oxygen penetration is measured in the films while at 800 °C, critical spalling occurs for all samples. The coating deposited at a temperature of 300 °C and negative bias of 100 V exhibits the most interesting compromise in both oxidation resistance and mechanical performances with a hardness of 40 GPa, a friction coefficient of 0.44 and a wear rate of 5.8 · 10−7 mm3·N−1·m−1. Annealing in air at 600 °C for 2h reduces the wear rate to 2.1 · 10−7 mm3·N−1·m−1 and the surface hardness to 17 GPa. Although annealing forms a thin oxide layer that reduces the hardness on the surface of the coating, it also averages the hardness inside the film to 33 GPa regardless of the deposition bias.

Microstructural and micro-mechanical investigation of cathodic arc evaporated ZrN/TiN multilayer coatings with varying bilayer thickness

Modifying the architecture of multilayer hard coatings allows to adjust the mechanical properties of these materials for a given application. Within this work, the effect of the bilayer thickness (Λ) and the individual sublayer thickness ratio on the microstructure and mechanical properties of ZrN/TiN multilayer coatings was investigated. Multilayer coatings with Λ of 570, 320 and 35 nm were deposited by cathodic arc evaporation and compared to TiN and ZrN single-layer coatings. The microstructure was investigated by X-ray diffraction (XRD) and scanning electron microscopy. All coatings exhibit a single phase face-centred cubic structure and a predominant (111) texture. A columnar structure was observed for all coatings and grain growth extending beyond the ZrN/TiN interfaces was evident in all multilayers. For all coatings, compressive residual stresses were determined by XRD using the sin 2 ψ method, where the multilayer sample with the largest Λ exhibited the highest compressive residual stress of −1.7 ± 0.2 GPa. Lower compressive residual stresses could be correlated with decreasing Λ and decreasing ZrN:TiN thickness ratio. Nanoindentation experiments as well as micro-mechanical bending tests were conducted to assess the mechanical properties of the coatings. The ZrN/TiN multilayer sample with Λ of 35 nm showed the highest hardness of 28.0 ± 1.1 GPa. This value is similar to the TiN single-layer and higher compared to the ZrN single-layer, which exhibited a hardness of 27.9 ± 1.4 GPa and 25.8 ± 1.3 GPa, respectively. While the ZrN single-layer showed the highest fracture toughness, the ZrN/TiN multilayer samples were identified as the mechanically stiffest and strongest of the investigated coatings, since they exhibited a higher fracture stress compared to the single-layer coatings. The obtained results allow to optimise the architecture of ZrN/TiN multilayer coatings yielding the desired coating properties for application in the cutting industry. • Arc evaporated ZrN/TiN multilayer coatings with varying bilayer thickness Λ • Smaller Λ leads to grain refinement and more pronounced (111) texture. • Multilayer coating with lowest Λ exhibits the highest hardness. • Highest fracture toughness for ZrN single-layer coating • Improved fracture stress for multilayers compared to single-layers

Influence of oxygen content on structure, thermal stability, oxidation resistance, and corrosion resistance of arc evaporated (Cr, Al)N coatings

(CrxAl1-x)(OyN1-y)ε coatings with different oxygen fractions were prepared by cathodic arc evaporation through variation of injected oxygen flux, and elaborated concerning structure, mechanical properties, thermal stability, oxidation resistance, and electrochemical properties. A moderate addition of O into (Cr, Al)N coatings generates a (Cr, Al)(O, N) solid solution with a face-centered cubic structure, whereas an additional corundum-structured (Cr, Al)2O3 solid solution is formed with superfluous oxygen introduced. The addition of O effectively improves the thermal stability by retarding the formation of w-AlN as well as the dissociation of the CrN bond, allowing the oxynitride coatings to maintain higher hardness after annealing. Notably, a small fraction of O-addition (e.g. 8 or 21 at.% in non-metal sublattice) enhances significantly the resistance against oxidation to above 1100 °C by facilitating the formation of a protective Al-rich oxide scale. Further incorporation of O gives rise to a development of oxide scale with unity elemental distribution and hence results in inferior oxidation resistance. Nevertheless, the O-rich oxynitride coatings provide better protection against electrochemical corrosion while the N-rich coatings exhibit higher corrosion current as well as lower polarization resistance compared to the CrAlN coating.

Amorphous Carbon Coatings with Different Metal and Nonmetal Dopants: Influence of Cathode Modification on Laser-Arc Evaporation and Film Deposition

In this study, the arc evaporation of pure graphite and composite cathodes with small amounts of metals (Mo, Fe) or nonmetals (B, Si) was investigated by means of a laser-arc process. Both specific aspects of the arc evaporation and the effects on the deposition of the doped and undoped carbon coatings were studied. The deposition rate, the chemical composition and the mechanical properties of the generated films were evaluated. In addition, the dependence of the deposition rate and the composition on the height position of the substrates in relation to the cathode were also the subject of the investigations. Finally, the erosion rate and the arc spot behavior on the cathode were analyzed. It is shown that homogeneously doped (t)a-C:X coatings can be reliably synthesized with the laser-arc technique. There are differences in the various properties of the coatings and the deposition rate. The latter is attributed in particular to the erosion behavior of the cathodes.