Cathodic Arc Deposition Research Articles

Friction wear characteristics of diamond-like carbon coatings in oils containing molybdenum dialkyldithiocarbamate additive

Diamond-like carbon (DLC) coatings are typically used to reduce the friction of sliding parts in automobiles. However, the utilization of DLC coatings in oils containing molybdenum dithiocarbamate (MoDTC) additive causes severe wear of these parts. In this work, we modified the compositions of DLC coatings by varying the cathodic arc deposition process conditions and investigated the effects of the modified compositions on the coating wear properties. The results showed that the wear loss of the DLC coatings increased with the increasing hydrogen concentration or ratio between the sp2- and sp3-hybridized carbon atoms. In addition, the molybdenum oxide species produced during the MoDTC decomposition interacted with the double bonds of the DLC coatings, leading to their cleavage.

Space-structure-fabricated and Ni Film-deposited hybrid fabrics for enhanced electromagnetic interference shielding

In this work, high-performance hybrid fabrics for electromagnetic interference-shielding were constructed via a novel approach of space-structure fabrication and Ni film deposition. First, the composite yarns containing stainless steel filaments and stainless steel staple fibers were weaved into fabric. Then, the surface of the fabric was coated with a Ni film by magnetic filtration cathodic vacuum arc deposition technology. Optical microscopy illustrated that stainless steel filaments and stainless steel staple fibers formed complex structures of conductive grids. Scanning electron microscopy and energy-dispersive spectroscopy confirmed that Ni was deposited to form a Ni film on the surface of the fabric. Research result shows that the electromagnetic interference shielding effectiveness of the hybrid fabrics was improved effectively through space-structure-fabricating and film-depositing. Film coating can improve the fabrics’ shielding effectiveness up to 12.14% under the same stainless-steel staple fibers content condition. As a result, the novel approach is an effective means for improving the shielding effectiveness of fabrics.

Hydrogen-free fluorinated DLC films with high hardness prepared by using T-shape filtered arc deposition system

Fluorinated diamond-like carbon (F-DLC) films have good surface properties. DLC films with high mechanical hardness are prepared using filtered arc deposition, which is a physical vapor deposition method. In this work, the fabrication of F-DLC films using filtered cathodic arc deposition while introducing a fluorocarbon gas was carried out, and the characteristics of the F-DLC films were investigated. The F-DLC films were deposited on Si and WC substrates using the T-shape filtered arc deposition (T-FAD) system while introducing fluorocarbon gases. The fluorocarbon gases used for this purpose were C3F8, C6F14, or C7F14. The F-DLC characteristics such as surface appearance, film structure, film density, nanoindentation hardness, substrate adhesion, and water contact angle were investigated. The characteristics of the fabricated DLC films were as follows: the fluorine content ranged from 0 to 22 at.%, film density ranged from 2.1 to 3.1 g/cm3, nanoindentation hardness ranged from 10 to 48 GPa, elastic modulus ranged from 140 to 360 GPa, and water contact angle ranged from 66 to 95°. In addition, the F-DLC films showed good adhesion strength on WC substrates. F-DLC films with high mechanical hardness and water repellency were obtained using T-FAD.

Tribology performance of CrAlSiN coatings deposited by pulsed current input cathodic arc evaporation

This study has explored the effect of cathodic arc evaporation technology using pulsed current input on the wear resistance of the CrAlSiN coatings. The input of arc source current was set by modulating arc pulsed current in the two ranges of 90/120 A as well as 90/150 A, respectively; and also set a constant current of 90 A for comparison. These different current inputting conditions were controlled to obtain three kinds of CrAlSiN coatings in cathodic arc deposition system. The results show that all the coatings have the specific B1-Rock salt structure indexed by their XRD patterns with the (111) and (200) diffraction peaks. The coatings deposited with the pulsed current as compared to that with constant current presents the higher hardness up 4145 HV. After the TGA/DSC analysis in atmosphere, all the coatings are stable up to 1000 °C. The result of tribology test also shows that the CrAlSiN coating deposited with the pulsed current of 90/150 A has the best wear resistance.

Corrosion properties of carbon ions implanted chromium coating prepared on CSS-42L aerospace bearing steel

In this work, carbon ions implanted chromium coating deposited on CSS-42L aerospace bearing steel by using the filtered cathodic vacuum arc deposition- metal evaporation vacuum arc duplex technique had been investigated. Film structure and properties after carbon implantation have been characterized by glancing incident XRD, AFM, SEM, TEM, AES, XPS and potentiodynamic polarization test. Carbon ions implanted chromium coating showed an increase in the pitting potential, promoting higher pitting corrosion resistance. The improvement was attributed to the reduction of surface roughness, the irradiated amorphous phase, the inert graphitic solid state carbon and the formation of nanocrystalline Cr2C and CrC.

Wear and Corrosion properties of CrSiCN coatings deposited by cathodic arc deposition process

In this study, three CrSiN based coatings were fabricated using cathodic arc deposition (CAD) technique. CrSiCN coatings were obtained by using metal plasma activated CAD process to decompose the C2H2 and N2 reactive gas. The analyzed CrSiCN coatings were obtained with higher hardness and smooth surface. With addition of Si (8.7 at.% ) and C (41 at.%) in the coatings, the hardness increased to Hv3300 which is resulted from the addition of CrCN and CNx new phases. Tribological test shows the coefficient of friction of CrSiCN down to 0.2 was observed with the addition of Si and C, related to hardness and smooth surface. However, the corrosion resistance of the CrSiN coating is better than that of CrSiCN coating in the 1M H2SO4 solution at room temperature.

Characterization of tantalum and tantalum nitride films on Ti6Al4V substrate prepared by filtered cathodic vacuum arc deposition for biomedical applications

This paper explores tantalum and tantalum nitride thin films produced by filtered cathodic vacuum arc deposition method as bio-stable surface treatment for Ti6Al4V titanium alloy. Effect of nitrogen to argon gas ratio on microstructure of the deposited film has been investigated. Corrosion behaviour of the films in simulated biological fluid solution was evaluated by electrochemical impedance spectroscopy. It was found that both the Ta and TaN films enhanced corrosion resistance of the Ti6Al4V substrate with the best protective characteristics achieved by the TaN film deposited at 0.25 N2/Ar gas ratio. The protective characteristic was attributed to the formation of tantalum oxide and oxynitride compound at the surface, as verified by X-ray photoelectron spectroscopy. Increasing N2/Ar gas ratio increased susceptibility to localized corrosion. The corrosion resistance decreased as the thickness of the film increased to 1 μm.

Effect of (Ti, Al)N Nanostructured Arc-Coatings on Wear and Corrosion Properties of 4340 Alloy Steel.

This study utilized cathodic arc deposition technology to coat Ti-Al-N hard films on AISI 4340 alloy steel. Composition, morphology, and structure of the coatings were analyzed using EPMA, FESEM, XRD, and TEM. Both wear tests and polarization tests were conducted to determine the abrasion and corrosion properties of the steel before and after coating. The results showed that a specific (Ti, Al)N nanostructured multilayer was synthesized smoothly. The multilayer consisted of 10 nm-TiN and 15 nm-TiAlN interaction layers. The coating not only greatly reduced the friction coefficient of AISI 4340 alloy steel from 0.81 to 0.45, but also provided an effective improvement in corrosion resistance.

The correlation between optical and mechanical properties of amorphous diamond-like carbon films prepared by pulsed filtered cathodic vacuum arc deposition

Diamond-like carbon (DLC) films were deposited by pulsed filtered cathodic vacuum arc (FCVA) deposition. The microstructure, mechanical and optical properties of DLC films have been investigated as functions of the variation in the substrate negative direct current bias voltage (Vbias) from 0.0 to 1.5 kV. Raman and X-ray photoelectron spectroscopy results show a correlation between the ID/IG ratio and the microstructure in terms of the sp3/sp2 ratio to Vbias. This fact shows that a significant change in the sp3 content, which is attributed to the transformation from graphite-like to diamond-like, is accompanied by a decreasing ID/IG ratio. The relatively high mass density of the films in the range of 2.51 to 2.79 g/cm3 can be obtained with biasing. The mechanical properties, i.e., the hardness and elastic modulus, were 13–25 and 114–145 GPa, respectively. The improvement of the mechanical properties is due to the formation of the compressive residual stress and the local density depending on Vbias. The relationship between the refractive index and the ID/IG ratio agree well with the microstructure and mechanical properties of DLC films. All of these results indicate a vital role of Vbias in determining the DLC properties.

Mechanical, wear, corrosion and biological properties of arc deposited titanium nitride coatings

Cathodic arc deposition of ceramic coatings is gaining importance due to their good adhesion and minimum residual stresses. In this work we have arc deposited TiN coatings on Ti6Al4V alloy and evaluated their mechanical, corrosion, in vitro tribological and biological properties for implant applications. Coatings exhibited high hardness of 33.4 ± 10 GPa and Young's modulus of 458.4 ± 79 GPa. Scratch tests revealed that the coatings fail adhesively at 2.9 ± 0.3 GPa. Hydrophilic nature of the coatings enabled protein adsorption leading to surface passivation and significant increase in the in vitro corrosion resistance. The inherent in vitro wear rate of the coatings was 6.8 ± 1.7 × 10−7 mm3/N·m against Al2O3 ball. The wear rate of ultrahigh molecular weight polyethylene tested against TiN coatings was 1.9 ± 0.7 × 10−5 mm3/N·m, which appears to be better than against CoCrMo alloy. In vitro biocompatibility studies performed using mouse embryonic fibroblast cell line (NIH3T3) demonstrated that the coatings are non-toxic and exhibit excellent cell-materials interactions. Further improvement in the performance of present cathodic arc deposited TiN coatings can be achieved by minimizing/eliminating coating defects such as pits and macro/micro particles, which accelerated the localized damage during articulation.

Cytocompatible tantalum films on Ti6Al4V substrate by filtered cathodic vacuum arc deposition

Tantalum films were deposited on negatively biased Ti6Al4V substrates using filtered cathodic vacuum arc deposition to enhance the corrosion resistance of the Ti6Al4V alloy. The effect of substrate voltage bias on the microstructure, mechanical and corrosion properties was examined and the cytocompatibility of the deposited films was verified with mammalian cell culturing. The Ta films deposited with substrate bias of −100V and −200V show a mixture of predominantly β phase and minority of α phase. The Ta/−100V film shows adhesive failure at the Ti/Ta interface and a cohesive fracture is observed in Ta/−200V film. The Ta/−100V showed a significant improvement in corrosion resistance, which is attributed to the stable oxide layer. The in-vitro cytocompatibility of the materials was investigated using rat bone mesenchymal stem cells, and the results show that the Ta films have no adverse effect on mammalian cell adhesion and spreading proliferation.

Superhard amorphous/nanocrystalline multilayer coatings for carbide inserts used for intermittent cutting

Ti-Al-Si-N coatings deposited by filtered cathodic vacuum arc deposition method are characterized by multilayer structure that corresponds to alternating layers of crystalline TiN with variable stoichiometry and amorphous Si3N4 with inclusions of hexagonal AlN grains. The thickness of the layers was 5–20 nm. The structure of coatings was regulated by rotation speed of the samples coated (n) in relation to evaporated cathodes and substrate bias voltage (Ub). The multilayer structure was not observed at the minimal energy of evaporated particles which is determined by the minimal Ub = − 60 V. Its separate areas were only observed in a limited volume of deposited coating. The grain structure of coatings was extremely heterogeneous. The distinct multilayer structure of coating with clear interphase boundary was formed when increasing Ub up to − 120 V. The reducing of layer thickness and corresponding grains were observed. The subsequent increase of Ub up to − 140 V leads to formation of sublayers 2–3 nm thick within the layers ~ 15 nm thick. The increasing of layer boundary length and refinement of coating grain structure are accompanied by increase of hardness from 33 to 56 GPa. The friction coefficient of the coatings obtained on carbide inserts is 0.60 as compared to 0.75 for the uncoated substrate (sliding wear tests against 100Cr6 balls under dry condition using a ball-on-disk method at high speed). During scratch test, the coatings were destructed according to the cohesion mechanism. The complete abrasion of the coating to the substrate was not observed up to load 90 N.

Optimization of cathodic arc deposition and pulsed plasma melting techniques for growing smooth superconducting Pb photoemissive films for SRF injectors

Superconducting photoinjectors have a potential to be the optimal solution for moderate and high current cw operating free electron lasers. For this application, a superconducting lead (Pb) cathode has been proposed to simplify the cathode integration into a 1.3 GHz, TESLA-type, 1.6-cell long purely superconducting gun cavity. In the proposed design, a lead film several micrometres thick is deposited onto a niobium plug attached to the cavity back wall. Traditional lead deposition techniques usually produce very non-uniform emission surfaces and often result in a poor adhesion of the layer. A pulsed plasma melting procedure reducing the non-uniformity of the lead photocathodes is presented. In order to determine the parameters optimal for this procedure, heat transfer from plasma to the film was first modelled to evaluate melting front penetration range and liquid state duration. The obtained results were verified by surface inspection of witness samples. The optimal procedure was used to prepare a photocathode plug, which was then tested in an electron gun. The quantum efficiency and the value of cavity quality factor have been found to satisfy the requirements for an injector of the European-XFEL facility.

Synergetic effect for improved deposition of titanium nitride films

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 (~1012 A/m2) 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 1017 to 1019 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.

Abrasive, hydroabrasive, and erosion wear behaviour of nanostructured (Ti,Al)N-Cu and (Ti,Al)N-Ni coatings

In this work, the wear resistance and fracture characteristics of (Ti,Al)N-Cu, (Ti,Al)N-Ni, and (Ti,Al)N coatings deposited onto a carbide substrate by the filtered cathodic vacuum arc deposition method were investigated comparatively under various loading and friction conditions. The (Ti,Al)N-Cu and (Ti,Al)N-Ni metal-ceramic coatings showed an equiaxial structure with a ceramic phase grain size of about 15–20 nm. The coatings showed a hardness of about 50 GPa and maintained their fracture toughness (the relative work of plastic deformation was ~65%). The (Ti,Al)N ceramic coating showed a columnar structure having elements with a diameter of about 120 nm. This coating exhibited a hardness of about 27 GPa and was characterized by a significantly lower fracture toughness (the relative work of plastic deformation was ~45%).The tribological properties of these coatings were examined at 20 and 500 °C. It was found that the metal-ceramic coatings showed significantly lower friction coefficient values (~0.56 and 0.61) than the ceramic coatings (~0.68 and 0.70).The fracture pattern of the metal-ceramic coatings was obtained by simulating their abrasive wear during a scratch test. Complete abrasion of the coatings was not observed until 90 N. Under similar tests, the (Ti,Al) N coating showed adhesive destruction by the separation of large fragments from the substrate. Complete coating wear was observed at a load of ~70 N.The erosion of the coatings during hydroabrasive treatment under multicycle impact loading was investigated. It was found that the nanostructured (Ti,Al) N-Cu and (Ti,Al)N-Ni coatings were 1.5 and 2 times less susceptible to wear than the (Ti,Al) N coating, respectively.The wear characteristics of the coatings were analysed on the basis of their structures and physical and mechanical properties, including their H/E and H3/E2 parameters, which denote the resistance of a material to elastic and plastic deformation respectively.

Specific Features of the Microstructure and Properties of Multielement Nitride Coatings Based on TiZrNbAlYCr

Multicomponent nanostructured coatings based on (TiZrNbAlYCr)N with a hardness as high as 47 GPa were obtained by cathodic arc deposition. The effect of partial nitrogen pressure PN (with constant bias potential U b =–200 V applied to the substrate) on the phase-composition variation, the size of crystallites, and their relation to the microstructure and hardness was investigated. An increase in the nitrogen pressure resulted in the formation of two phases with characteristic BCC (the lattice period is 0.342 nm) and FCC lattices with averaged nanocrystallite sizes of 15 and 2 nm. At a high pressure of 0.5 Pa, crystallites in the FCC phase with a lattice period of 0.437 nm grew in size to ~7 nm. The hardness of deposited coatings with larger (3.5 nm) FCC-phase crystallites and smaller (7 nm) BCC-phase crystallites was enhanced considerably.

The effect of the substrate temperature on the microstructure properties of the NiCrAl coating in cathodic arc deposition

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.

Study of the plasma behavior produced by a vacuum arc discharge for different cathode materials

Las técnicas asistidas por plasma han sido ampliamente utilizadas para la deposición de películas delgadas y recubrimientos metalúrgicos de alta calidad. La descarga luminiscente producida en la región entre electrodos y cámara de un arco catódico fue modelada. El comportamiento del plasma fue caracterizado para diferentes materiales del cátodo comúnmente utilizados en descarga de arco catódico. Se encontró que la temperatura electrónica, densidad y potencial eléctrico decrecen como función de la distancia desde la región de puntos catódicos. Sin embargo, la energía cinética del ion tiende a incrementar debido a la aceleración de los iones provenientes de la región central del arco. Nuestros resultados muestran que el arco catódico no es directamente afectado por el potencial del plasma de la descarga luminiscente y que el material del cátodo tiene una influencia importante en el comportamiento del plasma, principalmente debido a la conductividad eléctrica y térmica de cada material.

Особенности микроструктуры и свойств многоэлементных нитридных покрытий на основе TiZrNbAlYCr

AbstractMulticomponent nanostructured coatings based on (TiZrNbAlYCr)N with a hardness as high as 47 GPa were obtained by cathodic arc deposition. The effect of partial nitrogen pressure P _N (with constant bias potential U _ b =–200 V applied to the substrate) on the phase-composition variation, the size of crystallites, and their relation to the microstructure and hardness was investigated. An increase in the nitrogen pressure resulted in the formation of two phases with characteristic BCC (the lattice period is 0.342 nm) and FCC lattices with averaged nanocrystallite sizes of 15 and 2 nm. At a high pressure of 0.5 Pa, crystallites in the FCC phase with a lattice period of 0.437 nm grew in size to ~7 nm. The hardness of deposited coatings with larger (3.5 nm) FCC-phase crystallites and smaller (7 nm) BCC-phase crystallites was enhanced considerably.

Machinability Investigation of AISI 304 Austenitic Stainless Steels using Multilayer AlTiN/TiAlN Coated Carbide Inserts

In the present study, multilayer AlTiN/TiAlN coating is used for coating of cemented carbide inserts and those are used for machining of AISI304 austenitic steel with high speed. The cemented carbide inserts used, are fine grained K-Grade (K-20) and the coating is done with cathodic arc deposition technique (PVD). It has been observed that, for the coating thickness of 3.8 μm, the micro hardness of AlTiN/TiAlN was found to be 34 GPa.In experimentation, turning operation is carried out. The range of cutting speed was 100 to 340 m/min. Feed was kept in the range of 0.08 to 0.20 mm/revolution and the depth of cut is kept constant of 1 mm. Influence of cutting speed, feed and tool coating were studied on cutting force and average chip tool interface temperature. The interface temperature of 938°C was observed at 180 m/min cutting speed and feed 0.16 mm/revolution.The cutting speed was the major factor responsible for chip tool interface temperature variation where feed was responsible for cutting force. Cutting force and cutting speed showed inverse proportion with each other and no built up edges were found.