Filtered Arc Deposition System Research Articles

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.

Tribological Properties of High Hardness ta-CNx Coatings Deposited by Filtered Arc Deposition with Block-on-Ring Tribotester

Low friction and high wear resistance are strongly needed desired in boundary lubrication condition for industrial usage. Carbon nitride (CNx) coating is one of the promising materials, but the hardness of conventional CNx coating was only 10GPa of nanoindentation hardness. In order to coat high hardness ta-CNx, we developed a dynamic mixing deposition method combining the filtered arc deposition system and nitrogen ion beam source. Nitrogen content was controlled by the nitrogen partial pressure in the deposition. Nanoindentation result gave the hardness of ta-CNx from 75 to 70GPa, under the nitrogen content from 5 to 8 at.%. In order to clarify the tribological performance of ta-CNx coatings under the boundary lubrication, block on ring friction test was carried out. As a result, this new ta-CNx showed much higher wear resistance compared to the former soft CNx and hard ta-C coatings under PAO lubrication for the block-on-ring tribotester.

Mono- and multiple TiN(/Ti) coating adhesion mechanism on a Ti–13Nb–13Zr alloy

Mono- and multiple TiN(/Ti) coatings deposited on Ti–13Nb–13Zr alloy substrates by the filtered arc deposition system were examined using scratch testing and depth-sensing indentation in terms of the relationship between the coating adhesion, deformation mechanism, and microstructure, and mechanical properties at the film/substrate interface. The results show that multilayer TiN/Ti coatings offer a greater resistance to cracking and delamination than monolithic TiN coatings under the same conditions on the Ti–13Nb–13Zr alloys substrates. And increasing the number of layers for TiN multilayer coating improves the coatings adhesion. In contrast, for the coatings on the Ti–13Nb–13Zr alloys substrates that were heat-treated to a higher hardness, the limited deformation in the substrates improved remarkably the coating adhesion indiscriminately. The substrate mechanical properties play the major roles in controlling the coating adhesion, and increasing thickness and layers of the TiN multilayer have a limited improvement to the adhesion of coating.

Nanomechanical properties of TiCN and TiCN/Ti coatings on Ti prepared by Filtered Arc Deposition

Abstract Monolayer TiCN and multilayer TiCN/Ti coatings were deposited on the surface of Ti using the Filtered Arc Deposition System (FADS). Nanoindentation tests were performed on both coatings. The multilayer TiCN/Ti coating exhibited better ductility than the monolayer TiCN coating. The lattice constants of the coatings were characterized by X-ray diffraction. Transmission Electron Microscopy (TEM) was used to investigate the fracture behavior of the coatings. Inter-columnar, inclined and lateral cracks were found to be the dominant crack modes in the monolayer TiCN coatings while small bending crack and radial crack were the dominant crack modes in the multilayer TiCN/Ti coatings. The Finite Element Method (FEM) was used to simulate the indentation process. It was found that the Ti interlayer in the multilayer TiCN/Ti coating could efficiently suppress the fracture, which is responsible for the improved ductility of the multilayer TiCN/Ti coating.

Deformation Behavior and Wear Resistance of Hard TiCN and TiCN/Ti Coatings on Ti6Al4V Alloy

Monolayer titanium carbide nitride (TiCN) and multilayer TiCN reinforced titanium (Ti) are coated on the surface of Ti6Al4V alloy by Filtered Arc Deposition System (FADS). Surface chemical composition has been characterized by an X-ray diffraction (XRD). Wear resistance of TiCN coating and TiCN/Ti coating have been detected by hommel tester T1000. Hardness and deformation mechanisms of the multilayer coatings are investigated using depth-sensing indentation comparison with the monolayer TiCN coatings. Focused Ion Beam (FIB) and Transmission Electron Microscopy (TEM) are used to identify the fracture modes of the coatings. The TEM image observations show that the inclined crack is the dominant crack in the monolayer TiCN coating while small bending crack is the dominant crack in the multilayer TiCN/Ti coating. The Ti layer with good ductility could efficiently suppress the crack propagation and absorb more indent energy.

The mechanical behaviour of TiN and multi-layered coating of TiN/Ti on Ti6Al4V substrate during nano-indentation

Thin films of TiN mono-layer and TiN multi-layers that alternate with titanium (ductile) inter-layers were surface coated by filtered arc deposition system (FADS) onto Ti6Al4V substrates. The surface topography and chemical composition have been characterised by atomic force microscopy (AFM) and X-ray diffraction (XRD), respectively, and the fracture properties of coatings induced by nano-indentation with a sphere-cone tip have been investigated. Focused ion beam (FIB) and transmission electron microscopy (TEM) were used to identify the fracture modes. It was found that the multi-layer coating of TiN/Ti showed a higher pop-in force, which indicated good film ductility. Transmission electron microscope (TEM) observations showed that a small bending crack was the dominant crack in the TiN/Ti multi-layer coating but cracks along the inter-columnar and trans-granular cracks could be seen on the single TiN layer coating on Ti6Al4V. The Ti layer showed it could effectively suppress the propagation of cracks, which improved the ductility of the multi-layer coating of TiN/Ti. Finite element simulation (FEM) was used to simulate the indentation process and compare it with the experiment results.

AFM and Ellipsometry Studies of Ultra Thin Ti Film Deposited on a Silicon Wafer

An ultra- thin Ti film with a thickness of less than 30 nm was deposited on the surface of a silicon wafer by the filtered arc deposition system. A novel technique was adopted to create a height step between the coated area and non-coated area (silicon wafer) during deposition. The surface morphology and thickness of the film was detected by atomic force microscopy (AFM). The AFM results showed that the deposited film formed a smooth structure on the silicon wafer and the height step between the coating and silicon wafer was clear enough to give the thickness of the deposited film. The composition of the deposited film was detected by a combined use of Ellipsometry and AFM. Natural oxidisation of Ti (TiO2) was found on the top of the Ti film after deposition, and the thickness of TiO2 was determined by ellipsometry to be about 0.6 nm.

Development of Electromagnetically Pulled-Out Gas Plasma (EPOP) Gun for Medium Vacuum and its Fundamental Discharge Characteristics

Electromagnetically pulled-out gas plasma (EPOP) gun was developed, which will be applied to the filtered arc deposition system in order to enhance the nitriding of preparing thin film under medium vacuum. A hot cathode of tungsten (W) filament was employed and DC discharge was generated between the cathode and anode (SUS304). The distance of electrodes was 100 mm. Electromagnetic coils were placed around the cathode, anode and plasma pulled-out duct, separately. Experimental pressure was 0.1 Pa. The following results were obtained. Ignition voltage became lower when the same direction magnetic field was axially applied to the cathode and anode. Minimum voltage for sustaining the discharge became lower when the magnetic filed was applied to the anode. With increasing discharge voltage, the discharge current increased dramatically for the discharge voltage less than 50 V and increased gradually for the voltage more than that. The plasma between the cathode and anode was able to be pulled out to the process chamber by applying magnetic field perpendicular to the discharge axis. The amount of pulled-out plasma increased with increasing the filament current and magnetic flux density for plasma pulling-out.

T-shape filtered arc deposition system with built-in electrostatic macro-particle trap for DLC film preparation

A T-shape filtered arc deposition system (T-FAD) is a powerful tool to prepare high-quality diamond-like carbon (DLC) films. Most macro-particles (droplets) emitted from the graphite cathode are caught at the extension duct of the droplet catcher or collector facing the cathode, and then the clean plasma bent 90° is transported toward the substrate. However, further droplet reduction is still required in order to realize a higher quality film without droplet incorporation. In the present study, T-FAD employed an electrostatic droplet trap (ES-trap). A cylindrical ES-trap was placed in the extension duct part of the T-shape duct of an electromagnetic plasma transportation and droplet filter. The ion current at the exit of the T-filter duct and the current flowing to the ES-trap were measured as a function of the ES-trap bias voltage for various ES-trap positions. The deposition rate and number of droplets were also measured. As a result, it was found that the optimum voltage of the ES-trap was +35V and that it was better to place the ES-trap closer to the plasma beam in order to obtain fewer droplets on the film without an excessive decrease in the deposition rate. In the optimum condition, the number of droplets on the DLC film prepared with ES-trap was reduced to 1/3 of that without the ES-trap.

Cavitation erosion resistance of NiTi thin films produced by Filtered Arc Deposition

In this study, NiTi thin films were obtained by using a Filtered Arc Deposition System (FADS). X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Transmission Electron Microscopy (TEM) and Differential Scanning Calorimetry (DSC) were used to investigate the effect of substrate temperature (130–600 °C) on the structures and properties of NiTi thin films. It was found that FADS produced dense and homogenous films. Higher substrate temperatures resulted in crystalline thin films dominated by the parent phase (B2). The cavitation erosion resistance of the films was assessed by using ASTM Test Method G32. It was found that NiTi thin films showed superior cavitation erosion resistance compared with 316 austenitic stainless steel. The improved cavitation erosion resistance was attributed to the recoverable deformation associated with pseudoelasticity of the NiTi thin film.

Preparation of Super-DLC Film by Filtered Cathodic Arc Deposition

Diamond-like carbon (DLC) is usually classified into 4 kinds: tetrahedral amorphous carbon (sp3 rich), ta-C; amorphous carbon (sp2 rich), a-C; hydrogenated ta-C, ta-C:H; hydrogenated a-C, a-C:H. In this review paper, first, general properties of DLC, conventional preparation methods, and tutorial explanations of cathodic arc deposition and filtered arc deposition (FAD), are presented. New FAD systems designed especially for preparing droplet-free ta-C (super DLC) film with T- and X-shape filter ducts, T-FAD and X-FAD, are introduced. Some properties of above 4 kinds of DLC films, which were prepared by T-FAD under different conditions, were measured. Ta-C was the hardest and densest among the DLC films. Ta-C had a lower coefficient of friction than a-C:H prepared by plasma enhanced chemical vapor deposition (PECVD). X-FAD system made it possible to prepare thick ta-C film by employing interlayer of metal and graded DLC (a-C to ta-C).

Review of Cathodic Arc Deposition for Preparing Droplet-Free Thin Films

Cathodic arc plasma is one of the potential ion plating physical vapor deposition methods to prepare protective coatings on cutting tools, metal mold, etc. In particular, TiN, CrN, and TiAlN films are coated on industrial cutting tools using cathodic arc plasma. However, the cathode spot of the vacuum arc generates macrodroplets as coproducts of cathodic arc plasma containing high-energy ions. These macrodroplets may pose problems with smooth-surface films that are used for advanced high-precision applications. This paper reviews cathode phenomena particularly for a graphite cathode, the techniques for reduction of macrodroplet generation, and the techniques for macrodroplet removal from the processing plasma. The reduction technique includes steered arc, pulsed arcs, etc. The removal technique includes shielded arcs and filtered arcs. Recent filtered arc deposition systems are referred.

Tribological property enhancement of CrN films by metal vapor vacuum arc implantation of Vanadium and Carbon ions

CrN films have been extensively used in precision forming and molding applications because of their excellent tribological properties and oxidation-resisting characteristics. Vanadium and carbon ions are introduced into the near surface layer of deposited CrN films via metal vapor vacuum arc implantation to improve the wear performance of CrN films. Dense and smooth CrN film was deposited using a filtered arc deposition system, which provides fully ionized Cr plasma on the substrate surface. Subsequently, surface bombardment of the deposited CrN film with vanadium and carbon ions densifies the film and forms an alloy near the surface. These CrN-based films were characterized by X-ray photoelectron electron and Auger electron spectroscopies. Examinations of the tribological and mechanical film properties, including wear resistance, corrosion resistance and fracture toughness were performed and correlated with respect to the implantation parameters.

Characterisation of Ni–Ti thin films produced by filtered arc deposition

Ti–49.5 at%Ni thin films have been formed by deposition onto Si and glass substrates using a filtered arc deposition system (FADS). The films deposited on glass were composed of nanocrystalline parent phase grains contained within an amorphous matrix. The films deposited onto silicon were crystalline, and were largely parent phase whereas a bulk alloy of the same composition would be expected to be martensite. The stabilisation of the parent phase is proposed to be a grain size effect, with the critical grain size for parent phase stabilisation being about 30 nm.

Insulated Rail Joints for Signalling Applications

Insulated rail joint assemblies provide electrical insulation between two sections of rail for signalling purposes. In this work, rail steel was successfully bonded to PSZ ceramic using an active brazing technique. In order to increase the wettability of the PSZ ceramics, titanium coating was deposited on the ceramic surface using a filtered arc deposition system. A filler metal called BVAg-18 (60%Ag-30%Cu-10%Sn) was used and the joining was performed at a temperature of 750 °C. Bonding between partially stabilised zirconia and rail steel with BVAg-18 filler metal was not achieved using a standard brazing method. Bonding did occur with the BVAg-18 filler metal using the advanced brazing technique of active metal brazing, with best results obtained using a brazing temperature of 750oC and a dwell time of 10 minutes. The microstructure of the coating and joint interface were characterised by XRD, SEM and EDS.

Tribological behaviour and microstructure of TiC xN (1− x) coatings deposited by filtered arc

A series of macroparticle-free TiN, TiC x N (1− x) and TiC coatings were deposited on 316 austenitic stainless steel using a titanium target in a filtered arc deposition system (FADS) and reactive mixtures of N 2 and/or CH 4 gases. The surface topography, chemical composition and microstructure of these coatings were characterised by optical microscopy (OM), atomic force microscopy (AFM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The microhardness has been measured and the adhesion of the coatings has been evaluated. Further, the wear and friction behaviour of the coatings were assessed under controlled test conditions in a pin-on-disc tribometer. The results show a significant increase in surface roughness, microhardness and wear resistance as the CH 4:N 2 gas flow rate ratio is increased. The composition of the coatings was strongly dependent on reactive gas flow rate during deposition. Surface particles were observed on high carbon content coatings and subsequently determined to be carbonaceous particles by using OM, AFM and EDS. At lowest load (10 N), all coatings exhibited low friction and wear. At loads of 15 and 25 N, the higher carbon content TiCN and TiC coatings showed a much lower friction and wear compared to TiN and low carbon TiCN.

Evaluation of duplex coatings produced with a pulsed Nd:YAG laser and filtered arc

Duplex coatings combining a physical vapour deposition (PVD) thin film and laser-clad WC/Ni layer were produced on an austenitic steel substrate. PVD TiN, TiCN and TiC thin films were deposited using a filtered arc deposition system. Laser-clad WC/Ni layers were produced using a pulsed Nd:YAG laser and optical fibres. Mechanical properties (microhardness and adhesion) of the coatings were determined using a Ultra-Micro Indentation System (UMIS-2000) and adhesion scratch tester, respectively. The wear resistance of the duplex coatings was evaluated by a pin-on-disc wear tester. The results showed that increasing the concentration of carbon in the PVD thin films increases its hardness, reduces its adhesion to the clad layer and increases its wear resistance. All coatings withstood the applied loads (25 and 40 N) and no sign of breakthrough was observed on any of them. This indicated that the duplex coatings exhibited a significant increase in load-bearing capacity, confirming the pivotal role of the laser-clad layer in supporting the applied load.

Sliding wear behaviour of TiN coatings deposited by filtered arc

Filtered arc deposition system (FADS) is rapidly emerging as a powerful physical vapour deposition technology for the application of hard coatings. In this work, the tribological behaviour (friction and wear) of TiN coatings applied by FADS at 450°C was studied using a ball-on-disc configuration. The substrate bias voltages were systematically varied to investigate the effect of ion bombardment on the hardness, roughness, adhesion and wear resistance of the coatings. The hardness of coatings was determined using Knoop microhardness and an automatic scratch tester was used to assess the adhesion of the coatings. The wear behaviour and dominant wear mechanism(s) of coated and uncoated tool steels were investigated as a function of applied load and sliding distance. It has been found that, at low load (5 N), the wear behaviour of the uncoated tool steel was dominated by a mild oxidative wear regime. At higher load (20 N), a combination of adhesive and abrasive wear modes was operative and the wear tracks exhibited severe gouging. In the case of TiN coatings, the wear resistance, adhesion, roughness, and hardness of the coatings were strongly influenced by the substrate bias voltage. The optimum wear resistance, at both 5 and 20 N loads, occurred at 50–100 V substrate bias voltages. At zero bias voltage, the coating exhibited higher hardness but was exfoliated during wear tests owing to its brittleness. At the highest bias voltage (400 V), a reduction in adhesion and hardness was noticed, and the coating was delaminated from the substrate resulting in a high friction-high wear regime.