Filtered Vacuum Arc Deposition Research Articles

The Formation of Composite Ti-Al-N Coatings Using Filtered Vacuum Arc Deposition with Separate Cathodes

Ti-Al-N coatings were deposited on high-speed steel substrates by filtered vacuum arc deposition (FVAD) during evaporation of aluminum and titanium cathodes. Distribution of elements, phase composition, and mechanical properties of Ti-Al-N coatings were investigated using Auger electron spectroscopy (AES), X-ray diffraction (XRD), transmission electron microscopy (TEM) and nanoindentation, respectively. Additionally, tribological tests and scratch tests of the coatings were performed. The stoichiometry of the coating changes from Ti0.6Al0.4N to Ti0.48Al0.52N with increasing aluminum arc current from 70 A to 90 A, respectively. XRD and TEM showed only face-centered cubic Ti-Al-N phase with preferred orientation of the crystallites in (220) direction with respect to the sample normal and without precipitates of AlN or intermetallics inside the coatings. Incorporation of Al into the TiN lattice caused shifting of the (220) reflex to a higher 2θ angle with increasing Al content. Low content and size of microdroplets were obtained using coaxial plasma filters, which provides good mechanical and tribological properties of the coatings. The highest value of microhardness (36 GPa) and the best wear-resistance were achieved for the coating with higher Al content, thus for Ti0.48Al0.52N. These coatings exhibit good adhesive properties up to 30 N load in the scratch tests.

Deuterium permeation and retention behaviors in erbium oxide-iron multilayer coatings

Hydrogen isotope migration behaviors in ceramics-metal multilayer coatings have been elucidated for a further improvement of fueling system and radiological safety. Erbium oxide (Er2O3) coatings were fabricated by filtered vacuum arc deposition (VAD) on reduced activation ferritic/martensitic steel substrates. An iron (Fe) layer was fabricated by radio-frequency magnetron sputtering or covered with an Fe foil on the Er2O3 coating. An Er2O3-Fe-Er2O3 three-layer coating was also fabricated by the VAD on the Er2O3-Fe coating. The grain boundary diffusion model was constructed based on the results of grain structure analysis and deuterium depth profile for the Er2O3 single-layer coating from our previous works. The Er2O3-Fe two-layer coatings with different Fe layer thickness showed no significant difference in deuterium permeability. The Er2O3-Fe-Er2O3 three-layer coating showed a PRF of up to 104 due to a contribution of two diffusion barriers of the inner and outer Er2O3 layers. In addition, the three-layer coating had three times higher deuterium concentration than the Er2O3-Fe coating, although the concentration will be negligibly small from the perspective of tritium inventory in the fuel system.

Nanodiamond embedded ta-C composite film by pulsed filtered vacuum arc deposition from a single target

Detonation Nanodiamonds (DNDs) are known to have sp3 core, sp2 shell, small size (few nm) and are gaining importance as multi-functional nanoparticles. Diverse methods have been used to form composites, containing detonation nanodiamonds (DNDs) embedded in conductive and dielectric matrices for various applications. Here we show a method, wherein DND-ta-C composite film, consisting of DNDs embedded in ta-C matrix have been co-deposited from the same cathode by pulsed filtered cathodic vacuum arc method. Transmission Electron Microscope analysis of these films revel the presence of DNDs embedded in the matrix of amorphous carbon. Raman spectroscopy indicates that the presence of DNDs does not adversely affect the sp3 content of DND-ta-C composite film compared to ta-C film of same thickness. Nanoindentation and nanowear tests indicate that DND-ta-C composite films possess improved mechanical properties in comparison to ta-C films of similar thickness.

Effect of the substrate temperature and bias voltage on the properties of ZrO2/Al2O3 coatings produced by pulsed magnetron sputtering and filtered vacuum arc deposition

Effect of the substrate temperature and bias voltage on the properties of ZrO2/Al2O3 coatings produced by pulsed magnetron sputtering and filtered vacuum arc deposition

Swift heavy ion irradiation of metal containing tetrahedral amorphous carbon films

Thin carbon films were grown at room temperature on (001) n-Si substrate using dual cathode filtered vacuum arc deposition system. Graphite was used as a source of carbon atoms and separate metallic electrode was simultaneously utilized to introduce Ni or Cu atoms. Films were irradiated by 100MeV Ag7+ ions to fluences in the range 1×1010–3×1011cm−2. Rutherford backscattering spectroscopy, Raman scattering, scanning electron microscopy and atomic force microscopy in conductive mode were used to investigate film properties and structure change under irradiation. Some conductive channels having metallic conductivity type were found in the films. Number of such channels is less than number of impinged ions. Presence of Ni and Cu atoms increases conductivity of those conductive channels. Fluence dependence of all properties studied suggests different mechanisms of swift heavy ion irradiation-induced transformation of carbon matrix due to different chemical effect of nickel and copper atoms.

Multilayer composite nanoscale coatings as a method to increase reliability and tool life of cutting tools made of mixed ceramic Al2O3-TiC

The paper studies the challenges of improvement of reliability and tool life of ceramic cutting tools made of mixed ceramic Al2O3-TiC through application of nanoscale multilayer composite coatings, deposited through the method of filtered vacuum arc deposition. The paper studied wear mechanisms of ceramic cutting tools with and without coatings, as well as reliability of ceramic tools. It is found out that coatings reduce the wear rate of a ceramic tool along its flank face. The difference between flank wear land VB for an uncoated ceramic tool and a ceramic tool with coating reaches up to 60 μm during cutting time of 10–12 min, with the better results on reduction of the wear rate of flank wear land shown by ceramic cutting inserts with nanoscale multilayer coating Ti-(TiAl)N-(TiCrAl)N as compared with coating Ti-(TiAl)N-(ZrNbTiAl)N. The tests showed that failures of uncoated ceramic tools follow the exponential distribution law, and the coefficient of failure variation of such tool is 1.08. Meanwhile, the failures of coated ceramic tools follow the law of Weibull distribution, and the coefficients of failure variation are 0.39–0.45, respectively. Thus, it is found out that the deposition of multilayer composite coatings of recommended composition on working surfaces of a tool equipped with cutting inserts of mixed ceramic Al2O3-TiC provides the increased operating reliability of the ceramic tool and predicts its failures.

Thermal Stability of Filtered Vacuum Arc Deposited Er2O3 Coatings

Erbium oxide (Er2O3) coatings were deposited using filtered vacuum arc deposition (FVAD) and their structure and thermal stability were studied as a function of fabrication parameters. The coatings were deposited on silicon wafer and tantalum substrates with an arc current of 50 A and a deposition rate of 1.6 ± 0.4 nm/s. The arc was sustained on truncated cone Er cathodes. The influence of oxygen pressure (P= 0.40-0.93 Pa), bias voltage (Vb= -20, -40 or grounded) and substrate temperature (room temperature (RT) or 673K) on film properties was studied before and after post deposition annealing (1273K for 1 hour, at P~ 1.33 Pa). The coatings were characterized using X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Knoop Hardness. Optical microscope images indicated that the coatings had very low macroparticle concentration on their surface. The macroparticle diameters were less than 2.5 μm. The coatings were composed of only Er2O3 without any metallic phase under all deposition parameters tested. The coatings deposited on RT substrates were XRD amorphous and had a featureless cross-section microstructure. However, the coatings deposited on 673K heated substrates had a C-Er2O3 structure with (222) preferred orientation and weak columnar microstructure. The coating hardness varied with deposition pressure and substrate bias, and reached a maximum value of 10 GPa at P = 0.4 Pa and Vb = -40 V. The post-deposition annealing caused crystallization, and the coatings hardness dropped to 4 GPa with thermal treatment. However, after post-deposition annealing, no peeling or cracking appeared at the coating surface or the interface with the substrate.

The effect of Cu and Ni on the nanostructure and properties of arc-PVD coatings based on titanium nitride

Metal–ceramic TiN–Cu (TiN–Ni) coatings with metal contents from 0 to 20–26at.% can be synthesised by filtered vacuum arc deposition of carbide cutting tools. Adding metals into the coating reduces the nitride phase crystalline grain size from 100 to 20nm. Additionally, the enhancement of metal content in the coating of up to 3–5at.% results in an increase of the coating hardness from 20–22GPa (typical for TiN) to 45–50GPa and a decrease of the friction coefficient from 0.65 (typical for a hard alloy) to 0.45 (sliding wear tests against 100Cr6 balls under dry condition using a ball-on-disc method at high speed). Further enhancement of metal content up to 20at.%, which is accompanied by a reduction in the nitride phase crystalline grain size, results in a decrease in hardness by 15–19GPa due to additional introduction of soft ductile metal and emerging coating porosity. Adhesive/cohesive properties of coatings were investigated. It was established that the coatings were destroyed according to the cohesion mechanism. The critical loads characterising the emergence of the first cracks in the coatings and complete abrasion of the coating to the substrate (Lc1 and Lc3) were determined to be 14N and 80N, respectively. The formed coatings display stability of structure and composition for up to 800°C. Coated carbide tools with developed coatings have increased the lifetime 5 times for continuous cutting steels (35HGSA) and more than 3 times for interrupted cutting steels (Cf53).

Structural and optical characteristics of filtered vacuum arc deposited N:TiOx thin films

Nitrogen doped titanium oxide (N:TiOx) thin films were deposited using filtered vacuum arc deposition. The X-ray diffraction patterns of the TiO2 thin films deposited in a pure oxygen environment indicated that films were polycrystalline in the anatase phase, while films deposited in an atmosphere in which the N2 fraction was greater than 9% were amorphous, for substrate temperatures up to 500°C. Annealing at 400°C in N2 for 1h generated polycrystalline films with anatase phase, independent of %N2 during deposition. Film surface roughness increased from 0.5 up to 3.2nm when the substrate temperature was increased from room temperature to 500°C for films deposited in a 41%N2.X-ray photoelectron spectroscopy analysis indicated that all films deposited in pure oxygen were stoichiometric TiO2. N content in the films increased with %N2 in the deposition atmosphere, however the N-content in the film, 1-5at.%N, was much less than that in the gas mixture (9–69%N2). Annealing decreased the N-content in these films to <1at.%. In addition, the data revealed that all N:TiOx films had two main N 1s components, at 396–397eV and at 399–400eV, associated with substitutional and interstitial nitrogen, respectively.Transmission data indicated that the average transmission of films deposited at lower N2 partial pressures (<41%) was approximately 80%, and it decreased to ~50% for higher %N2. The absorption edge of the films shifted to longer wavelengths with increased substrate temperature and %N2, from ~380nm up to ~485nm for films deposited with 41%N2 and a substrate temperature of 500°C.

Electrical, optical, and structural properties of thin films with tri-layers of AZO/ZnMgO/AZO grown by filtered vacuum arc deposition

Abstract Transparent conductive oxides (TCO) are indispensable as front electrode for most of thin film electronic devices such as transparent electrodes for flat panel displays, photovoltaic cells, windshield defrosters, transparent thin film transistors, and low emissivity windows. Thin films of aluminum-doped zinc oxide (AZO) have shown to be one of the most promising TCOs. In this study, three layered Al-doped ZnO (AZO)/ZnMgO/AZO heterostructures were prepared by filtered cathodic arc deposition (FCAD) on glass substrates. The objective is to find a set of parameters that will allow for improved optical and electrical properties of the films such as low resistivity, high mobility, high number of charge carriers, and high transmittance. We have investigated the effect of modifications in thickness and doping of the ZnMgO inner layer on the structural, electrical, and optical characteristics of the stacked heterostructures.

Effects of aluminium doping on zinc oxide transparent thin films grown by filtered vacuum arc deposition

Abstract Thin n-type ZnO films doped with different atomic concentrations of aluminium were grown by filtered vacuum arc deposition (FVAD) on glass substrates. The films were deposited using an oxygen working pressure of 2.0 mTorr with an arc current running at two 100 ms pulses s−1. Structural, optical and electrical properties were investigated to understand the effect of Al doping on ZnO films. The best values were found for an ideal aluminium percentage between 4 and 6 at.%.

The Effect of Nitrogen Partial Pressure and Substrate Temperature on the Characteristics of Photocatalytic N:TiO2 Thin Films deposited by Filtered Vacuum Arc Deposition

Nitrogen doped Titanium Oxide (N:TiO2) thin films were deposited using filtered vacuum arc deposition, and their structure, composition and morphology were studied as functions of the total pressure, N2/O2 gas ratio and the substrate temperature. The film structure, surface morphology, and composition were determined by XRD, AFM and XPS. The optical characterization of the films was determined with spectrophotomery and ex-situ variable angle spectroscopic ellipsometry (VASE). In addition to the effects of other deposition conditions such as arc current, total deposition pressure, and post-deposition annealing on the film characteristics, photocatalytic activity was also determined as a function of deposition parameters and results were discussed.

Erosion Wear Resistance of TiAlCrN Coating on Stainless Steel Impacted by Solid Particles

TiAlCrN coating was deposited on a stainless steel using unbalanced magnetron sputtering technique. The erosion wear resistance of the TiAlCrN coating was investigated by comparison with that of the TiN coating deposited by filtered vacuum arc deposition. SEM was used for observing the surface morphologies of coatings both the un-eroded and eroded. Scratch test was used to evaluate the adhesion of the coatings. The erosion wear was tested with a gas blast apparatus at room temperature. In the test, the coatings were impacted at an impingement angle of 90° by angular SiC solid particles with an average diameter of 124um. The maximum depth of the erosion scar measured by the optical profiler was used to evaluate the erosion wear loss of the coatings. TiAlCrN coating proved to have much lower erosion rate than TiN coating. Unlike TiN coating, the TiAlCrN coating behaved like semi-brittle material.

Erosion Wear Behavior of TiAlCrN Coating on Hard Metal Impacted by Solid Particles

The erosion wear resistance of TiAlCrN coating on a hard metal deposited using unbalanced magnetron sputtering technique was investigated by comparison with that of the TiN coating deposited by filtered vacuum arc deposition. SEM was used for observing the surface morphologies of coatings both the un-eroded and eroded. Scratch test was used to evaluate the adhesion of the coatings. The erosion wear was tested with a gas blast apparatus at room temperature. In the test, the coatings were impacted at an impingement angle of 90° by angular SiC solid particles with an average diameter of 124um. The maximum depth of the erosion scar measured by the optical profiler was used to evaluate the erosion wear loss of the coatings. TiAlCrN coating proved to have much lower erosion rate than TiN coating. Different from the typical brittle erosion behavior of TiN coating, the TiAlCrN coating behaved like a semi-brittle material.

Erosion Wear Behavior of Coatings with Growth Defects Produced by Ion Beam Enhanced Pulsed Filtered Vacuum Arc Deposition

The erosion wear behavior of TiN coatings with growth defects was studied. The TiN coatings were produced on a hard metal by ion beam enhanced pulsed filtered vacuum cathode arc deposition. The erosion wear was tested with a gas blast apparatus. In the test, TiN coatings were impacted at an impingement angle of 90° by angular SiC solid particles with an average diameter of 124um. The maximum depth of the erosion scar measured by the optical profiler was used to evaluate the erosion wear loss of the coatings. The coatings proved to have much lower erosion rate than that of the substrate material and consequently, the erosion rate increased significantly to the high level of the hard metal substrate after the coatings were penetrated. The failure mechanism was revealed by examining the surface morphologies of the coatings before and after the erosion test. The erosive wear of the TiN coatings with growth defects behaved as typical brittle materials. The damage mechanism of the coatings with growth defects was described.

Phase determination of filtered vacuum arc deposited TiO 2 thin films by optical modeling

Thin films of TiO 2 were produced using filtered vacuum arc deposition. Arc currents were 275, 300, 325 A, and the oxygen pressure during deposition was 0.93 Pa. The substrates were glass microscope slides, at temperatures of 25 °C (RT), 200 °C, and 400 °C. Film thickness was in the range 100 to 250 nm, depending on the deposition conditions. Film structure and chemical composition were determined using XRD and XPS analyses, respectively. As-deposited films were amorphous, except to two samples that were found to be crystalline (deposited with 300 A, 325 A at 400 °C), and the crystalline phase was close to that of anatase. All of the films were partially crystallized by annealing in air at 450 °C for 1 h. The O:Ti atomic concentration ratio was in the range 1.6:1–2:1, independent of deposition conditions. The optical parameters, refractive index and the extinction coefficient of the films were determined using variable angle spectroscopic ellipsometry. In addition, the optical transmission of the films were determined in the UV–VIS and IR regions. The average optical transmission in the VIS spectrum was 70–85%, affected by the interference in the film with 90% maxima and 60% minima. The refractive index at λ = 550 nm was in the range 2.4 to 2.7, depending on the deposition conditions and annealing. Using the semi-empirical model of Wemple and DiDomenico for the dielectric function below the interband absorption edge of ionic and covalent solids, the dispersion energy parameters of TiO 2 ( E o, E d) were calculated. The underlying structural order of the amorphous films was inferred by comparing the dispersion energy parameters of the amorphous films with those of crystalline TiO 2. As expected, the refractive index of the amorphous films depended on the underlying phase of the film. The optical analyses indicated that the underlying phase of the amorphous films deposited on RT substrates was close to anatase, whereas the underlying phase of the amorphous films deposited on 400 °C substrates and annealed at 450 °C for 1 h consisted of both anatase and rutile. Thus, although the XRD analyses could not indicate the underlying phase of the amorphous films, it could be determined by the optical analyses.

Properties of SnO 2 films fabricated using a rectangular filtered vacuum arc plasma source

Transparent and conducting SnO 2 films of 57–200nm thickness were deposited on microscope glass slide substrates, using a rectangular filtered vacuum arc deposition system. The 40 glass slides were equally distributed on a 400 × 420mm substrate carriage, and were exposed to a Sn plasma beam, produced by a rectangular vacuum arc plasma gun with a Sn cathode, and passed through a rectangular magnetic macroparticle filter towards the substrates. The carriage with the substrates was transported past the 94 × 494mm filter outlet. The SnO 2 films were fabricated on the glass substrates at room temperature by maintaining the chamber oxygen background pressure at 0.52Pa. The film composition, and electrical and optical properties were studied as a function of the film thickness. The films were stored under ambient air conditions, and their electrical resistance was measured as a function of storage time over a period of several months. The average resistivity of films was 10–17mΩ cm for films with thickness ( t) less than 100nm, but that of t > 100nm it was 5–9mΩ cm. The resistivity of the films with t > 100nm did not change significantly after 8months of storage in ambient air. The optical transmittance of the films in the visible spectrum was in the range of 75–90%. The optical constants, i.e., the refractive index and the extinction coefficient of the films at wavelength λ = 550nm were in the range of 2.02–2.09 and 0.013–0.023, respectively, and the optical band gap energy was 4.15–4.21eV. Unlike the electrical resistivity, the optical parameters weakly depended on t.

Optical and structural characteristics of tin oxide thin films deposited by filtered vacuum arc and spray pyrolysis

AbstractTin oxide (SnO2) thin films were deposited on commercial microscope glass and UV fused silica substrates (UVFS) using spray pyrolysis and filtered vacuum arc deposition (FVAD) system. During deposition, the substrates temperature was kept at 400 °C. The structure and composition were determined using X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS), respectively. The XRD patterns of SnO2 thin films deposited with the two systems on hot substrates were found to be polycrystalline. The average transmission of the films in the VIS was 80% to 85%. The film optical constants were determined by normal incidence transmission measurements. The refractive indices of FVA deposited films were in the range 2.11 to 2.0, and those of spray deposited ones were 1.97 to 1.93. The extinction coefficients of the deposited films were in the range 0.29 and 0.11 to approximately 0 for FVAD and spray pyrolysis, respectively, depending on wavelengths. The optical band gap, Eg, was determined from the dependence of the absorption coefficient on the photon energy at short wavelengths, and were 3.80 eV and 3.90 eV for spray pyrolysis and FVA deposited SnO2 thin films, respectively. (© 2007 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Characteristics of filtered vacuum arc deposited ZnO–SnO 2 thin films on room temperature substrates

ZnO, SnO 2 and zinc stannate thin films were deposited using filtered vacuum arc deposition (FVAD) system on commercial microscope glass and UV fused silica substrates (UVFS) at room temperature (RT). The structural and morphological analyses were performed using X-ray diffraction (XRD) and Atomic Force Microscopy (AFM), respectively. XRD patterns of ZnO films deposited at RT had strongly c-axis orientation, whereas SnO 2 and zinc stannate films had amorphous structure as they did not have any defined patterns. Average crystalline size and surface grain size of ZnO films were ∼16 nm, as determined from diffraction line broadening and AFM images, respectively. Optical constants in the 250–1100 nm wavelength range were determined by variable angle spectroscopic ellipsometry and transmission measurements. The transmission of the deposited films in the VIS was 80–90%, affected by interference. The refractive indices and the extinction coefficients of deposited ZnO, SnO 2 and zinc stannate films were in the range 1.87–2.15 and 0.02–0.04, depending on wavelengths and deposition parameters. The optical band gap ( E g) was determined by the dependence of the absorption coefficient on the photon energy at short wavelengths. Its values for ZnO, SnO 2 and zinc stannate were in the range 3.25–3.30 eV, 3.60–3.98 eV and 3.43–3.52 eV, respectively, depending on the deposition pressure.

Chemical and thermal stability of the characteristics of filtered vacuum arc deposited ZnO, SnO2 and zinc stannate thin films

ZnO, SnO2 and zinc stannate thin films were deposited on commercial microscope glass and UV fused silica substrates using filtered vacuum arc deposition system. During the deposition, the substrate temperature was at room temperature (RT) or at 400 °C. The film structure and composition were determined using x-ray diffraction and x-ray photoelectron spectroscopy, respectively. The transmission of the films in the VIS was 85% to 90%. The thermal stability of the film electrical resistance was determined in air as a function of the temperature in the range 28 °C (RT) to 200 °C. The resistance of ZnO increased from ∼ 5000 to 105 Ω when heated to 200 °C, that of SnO2 films increased from 500 to 3900 Ω, whereas that of zinc stannate thin films increased only from 370 to 470 Ω. During sample cooling to RT, the resistance of ZnO and SnO2 thin films continued to rise considerably; however, the increase in the zinc stannate thin film resistance was significantly lower. After cooling to RT, ZnO and SnO2 thin films became practically insulators, while the resistance of zinc stannate was 680 Ω. The chemical stability of the films was determined by immersing in acidic and basic solutions up to 27 h. The SnO2 thin films were more stable in the HCl solution than the ZnO and the zinc stannate thin films; however, SnO2 and zinc stannate thin films that were immersed in the NaOH solution did not dissolve after 27 h.