Cathodic Arc Deposition Research Articles

Design and hemocompatibility of the micro–nano multiscale patterns of TiO2 nanowires/carbon composite films

The micro–nano multiscale patterns of TiO2 nanowires/carbon composite films with three different topographies are fabricated by combining photolithography, hydrothermal method and pulsed magnetic filtered cathodic vacuum arc deposition. The hemocompatibility of the micro–nano multiscale patterned composite films is assessed by the platelet adhesion test in vitro. Results show that the fewer platelets are adhered on the patterned TiO2 nanowires/carbon composite films, indicating that the surface topography of the micro–nano multiscale patterns is a key factor in regulating the platelet behavior. The analysis demonstrates good correlation between the platelet coagulation behavior and the micro–nano multiscale effect, which leads to less effective surface contact area and less possibility of platelet variation. It suggests that the design of micro–nano multiscale patterns should be a promising technology to improve the hemocompatibility of implantable medical devices.

Influence of Al concentration on structural and optical properties of Al-doped ZnO thin films

Undoped ZnO and Al-doped zinc oxide (ZnO:Al) thin films with different Al concentrations were prepared onto Si (100) substrate by pulsed filtered cathodic vacuum arc deposition system at room temperature. The influence of doping on the structural and optical properties of thin films was investigated. The preferential (002) orientation was weakened by high aluminum doping in films. Raman measurement was performed for the doping effects in the ZnO. Atomic force microscopy images revealed that the surface of undoped ZnO film grown at RT was smoother than that of the Al-doped ZnO (ZnO:Al) films. The reflectance of all films was studied as a function of wavelength using UV–Vis–NIR spectrophotometer. Average total reflectance values of about 35 % in the wavelength range of 400–800 nm were obtained. Optical band gap of the films was determined using the reflectance spectra by means of Kubelka–Munk formula. From optical properties, the band gap energy was estimated for all films.

Structural and electrical properties of nitrogen-doped ZnO thin films

ZnO and nitrogen-doped ZnO thin films were prepared onto glass substrate by pulsed filtered cathodic vacuum arc deposition (PFCVAD) system at room temperature. The influence of doping on the structural, electrical and optical properties of thin films was investigated. XRD studies were carried out to analyze and compare the structural quality of undoped and nitrogen-doped ZnO films. Raman measurement was performed to study the doping effects in the ZnO. The optical transmittances of all films are studied as a function of wavelength using UV–VIS–NIR spectrophotometer. The optical band gap values of the films are found using absorbance spectrums. The electrical studies for the films are carried out by using Hall-effect measurements.

Thermal Behavior of AlTiN Free-Standing Coating by Cathodic Arc Deposition

(Ti,Al)N coatings possess superior hardness, good thermal and chemical stability. To further study the oxidation resistance, the arc-deposited AlTiN bulk material was collected from the substrate shutter of a commercial coating system deposited for over 100 batches. The thermal behaviour of the materials was studied by TGA/DSC with different annealing temperature or different atmospheres. The results show that AlTiN bulk material annealed in nitrogen exhibits the denser structure and thermal stability up to 1000°C. The oxidation resistance of the AlTiN can reach to 800°C. Annealed at 600 ~ 700°C proceed the recrystallization process which denser the structure. New phase of TiO2is formed by incorporate oxygen in exchange of nitrogen. nanoscaled 1D wire formation occurred at the 1000°C for 3 hours in air.

Effects of filtered cathodic vacuum arc deposition (FCVAD) conditions on photovoltaic TiO2 films

• Titanium dioxide films were synthesized using the FCVAD technique. • Various FCVAD conditions were tested. • The TiO 2 films were characterized. • The FCVAD condition effects on the film characteristics were studied. • The O 2 pressure had the most important effect on the film quality. Titanium dioxide (TiO 2 ) films for photovoltaic applications were synthesized using filtered cathodic vacuum arc deposition (FCVAD) technique. Various deposition conditions were tested for an optimal film formation. The conditions included the oxygen (O 2 ) pressure which was varied from a base pressure 10 −5 to 10 −4 , 10 −3 , 10 −2 and 10 −1 Torr, sample holder bias varied using 0 or −250 V, deposition time varied from 10, 20 to 30 min, and deposition distance varied from 1 to 3 cm. The deposited films were also annealed and compared with unannealed ones. The films under various conditions were characterized using optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS) and Raman spectroscopy techniques. The film transparency increased and thickness decreased to a nanoscale with increasing of the O 2 pressure. The transparent deposited films contained stoichiometric titanium and oxygen under the medium O 2 pressure. The as-deposited films were TiO 2 containing some rutile but no anatase which needed annealing to form.

真空熱処理における NiCrAlY コーティングと Nb 基材間の相互拡散層の形成

The formation of the inter-diffusion layer between NiCrAlY coating and Nb substrate during vacuum heat treatment was investigated. A NiCrAlY coating was applied on Nb substrate by cathode arc deposition. Vacuum heat treatments were carried out at 800, 900, and 1000°C for 2h. SEM, EPMA, EDS, and XRD were performed to analyze the microstructure of the inter-diffusion layer and the results were interpreted using the 1002°C isothermal ternary Nb-Ni-Cr phase diagram. It was found that at 800°C the inter-diffusion layer has a single NbNi3 layer; at 900°C the inter-diffusion layer consists of an outer NbNi3 layer, a thin intermediate NbCr2(HT) layer, and an inner Nb7Ni6 layer; at 1000°C the interdiffusion layer has three well-developed layers of an outer NbNi3 layer, an inner Nb7Ni6 layer, and an intermediate layers comprising NbCr2(HT) and NbNi3. A small amount of Cr exists in both the NbNi3 and the Nb7Ni6 phases as solid solution, and a large amount of Ni in the NbCr2(HT) phase as solid solution. [doi:10.2320/matertrans.M2014350]

Nano-scale Multilayered Composite Coatings for Cutting Tools Operating under Heavy Cutting Conditions

The aim of this work was to create a methodology for the development of wear-resistant coatings. These coatings were deposited on the working surfaces of carbide inserts which were used for rough re-profile machining of railway wheels-sets. The coatings were formed using a filtered cathodic vacuum arc deposition (FCVAD). An investigation into the effect of the FCVAD process parameters on the composition and properties of the coatings was undertaken. The experimental work replicated industrial application conditions in terms of cutting speed (40- 80 m/min), feed rates (0.8-1.2mm/rev) and depth of cuts (4.0-8.0mm). An increased tool life was achieved using carbide inserts with nanostructured multilayer composite coatings based on the Ti-TiN-TiAlCrN compound. The paper presents the results of carbide inserts with newly developed coatings for heavy duty machining of railway wheel-sets. The main coatings parameters i.e. microhardness, thickness, strength of adhesion of “coating-substrate” and surface morphology were studied. The nano-scale grain structure and thickness of sublayers for each coating component allowed achieving a balanced wear of rake and flank surfaces without micro/macro chipping of contact areas and cutting edge of the inserts. The results presented here show that the cutting tool life of the inserts with the new wear-resistance coatings exceeded commercial coated tools by a factor of more than two.

Annealing effects of ZnO thin films on p-Si(100) substrate deposited \newline by PFCVAD

In this study, ZnO films were prepared on p-Si substrates using the pulsed filtered cathodic vacuum arc deposition (PFCVAD) method. We report the effect of annealing temperature on structural and optical properties. The crystallographic structure and the size of the crystallites in the films were studied by means of X-ray diffraction. The films had a weak peak (100) orientation at 2theta = sim 32°. X-ray diffraction analysis of the as-deposited ZnO and the film annealed at 850 °C showed a strong ZnO (002) diffraction peak centered at 34.1° and 34.5°, respectively. The (004) peak was seen for film annealed at 850 °C. ZnO film annealed at 850 °C had higher grain size and better crystallinity. Optical properties of the ZnO films were studied using a UV-Vis-NIR spectrophotometer. The optical band gap of the films was determined using the reflectance spectra by means of the Kubelka-Munk formula. From the optical properties, the band gap energy estimated for films as-deposited and annealed at 850 °C was 3.00 and 3.28 eV, respectively. The Raman scattering spectra of the films was observed at a laser power of 2 mW.

XRD, XPS, and optical characterizations of Al-doped ZnO film grown on GaAs substrate

A ZnO:Al (10%) thin film was prepared on GaAs(100) substrate by using a pulsed filtered cathodic vacuum arc deposition (PFCVAD) system. The ZnO:Al thin film was thermally annealed for 1 h at 2 different temperatures in air. The film structure was investigated as a function of annealing temperature by X-ray diffraction (XRD). ZnO:Al film annealed at 500 °C by PFCVAD method resulted in an amorphous film. However, after annealing ZnO:Al film at 600 °C, it showed (100) and (002) peaks at around 32° and 34°, respectively. The chemical state of ZnO:Al (AZO) film on GaAs substrate was investigated by using X-ray photoelectron spectroscopy (XPS). The dependence of optical properties on annealing was investigated by using a UV-VIS-NIR spectrophotometer. We also obtained the energy gap of ZnO:Al thin film by diffused reflectance spectra using the Kubelka--Munk function.

Cell Adhesion on Cathodic Arc Plasma Deposited ZrAlSiN Thin Films

Interaction between ZrAlSiN thin films and osteoblasts cells was conducted in vitro. Ti and ZrAlSiN films were deposited on glass coverslips by cathodic arc deposition. Ti, ZrAlSiN thin films and the bare glass coverslips were cultured with human osteoblast cells (hFOB). Cell morphology was observed with a confocal microscope in the bright field mode. Cell viability was assayed by MTT. Cell proliferation was fluorescent visualized at 10 X magnification. Cell cytoskeletons were analyzed by observing actin stress fiber organization. Focal contact adhesion was studied by investigation of the density of the vinculin. Cell viability, cell proliferation, developed actin stress fibers and focal contact adhesion were found better on ZrAlSiN thin films than on Ti thin films or glass surfaces.

Effect of the Bias Voltage on the Structure, Mechanical, Electronic and Optical Properties of the Low Temperature ZnO Thin Films Deposited by Using Cathodic Vacuum Arc Deposition System on Plastic Substrates

The un-doped zinc oxide (ZnO) films on the polyethylene terephthalate (PET) substrate at a low temperature (<75°C) by using cathode vacuum arc deposition (CVAD) system with different negative substrate bias voltage applied between 0 and -100 V. The material, mechanical, optical and electrical properties were investigated and discussed. The results show that all ZnO thin films have (002) preferred orientation, an average transmittance was over than 70 % in the visible region. Calculated band gap values are all around 3.2 eV with the different substrate bias voltages. The ZnO thin films with resistivities as low as 10-3 Ω*cm have been obtained by adjusting the substrate bias voltage on the plastic substrates.

Temperature dependence of the residual stresses and mechanical properties in TiN/CrN nanolayered coatings processed by cathodic arc deposition

Nanolayered TiN–CrN coatings were synthesized by cathodic arc deposition (CAD) on M2 tool steel substrates. The aim of this study was to establish a double-correlation between the influence of the bilayer period and the deposition temperature on the resulting mechanical–tribological properties.The superlattice hardening enhancement was observed in samples deposited at different temperatures — i.e. without additional heating, 300°C and 400°C. Nonetheless, the residual compressive stresses are believed to be the responsible for reducing the hardness enhancement when the deposition temperature was increased. For instance, sample deposited without additional heating presented a hardness of 48.5±1.3GPa, while by increasing the processing temperature up to 400°C it was reduced down to 31.2±4.1GPa due to the stress relaxation. Indeed, the sample deposited at low temperature which possesses the thinnest bilayer period (13nm) exhibited better mechanical properties. On the contrary, the role of the interfaces introduced when the period is decreased seems to rule the wear resistance.

Development of Assisted Filtered Cathodic Vacuum Arc Deposition of Nano-Dispersed Multi-Layered Composite Coatings on Cutting Tools

This paper presents the results of development and application of processes for modification of various properties of working surfaces of cutting tools by condensing vapor and ion flows in assisting impulse or constant exposure to high-energy ions. The paper shows features of the technology and equipment for the formation of wear-resistant components, which modify the structure and properties of working surfaces of various edge cutting tool types in a wide range of temperatures, in order to improve tool life and reliability. Various properties of the modifying components were studied, and their ability to improve the operational efficiency of different types of carbide cutting tools for cutting various materials was shown.

Development and Research of Nanostructured Multi-Layered Composite Coatings for Tool Made of Tungsten-Free Carbides (Cermets)

This paper discusses the issues of improving the efficiency of cutting tool made of tungsten-free carbides (cermets) by using nanodispersed multi-layered composite coatings formed by use of innovative processes of filtered cathodic vacuum arc deposition (FCVAD). The paper presents the concept of architecture of nanostructured multi-layered composite coatings, methodology for choice of function and rational component parameters of architecture for tools made of cermets. Developed compositions of nanostructured multi-layered composite coatings contributes to significant improvement of properties of cutting tool made of cermets in cutting constructional steel and expansion of their application area for machining of heat-resistant alloys.

Annealing effect of thermal spike in MgO thin film prepared by cathodic vacuum arc deposition

MgO films were prepared by using pulsed cathodic vacuum arc deposition technique. The substrate bias voltage was in the range of −150 to −750 V. Film structure was investigated by X-ray diffraction (XRD). The annealing effect of thermal spike produced by the impacting of energetic ions was analyzed. The calculated results showed that the lifetime of a thermal spike generated by an energetic ion with the energy of 150 eV was less than one picosecond and it was sufficient to allow Mg2+ or O2- to move one bond length to satisfy the intrinsic stress relief in the affected volume. The MgO(200) lattice spacings of the films deposited at different bias voltages were all larger than the ideal value of 2.1056 Å. As the bias amplitude increased the lattice spacing decreased, which indicated that the compressive stress in the film was partially relieved with increasing impacting ion energy. The stress relief also could be reflected from the film orientation with bias voltage. The biaxial elastic modulus for MgO(100), MgO(110) and MgO(111) planes were calculated and they were M(100) = 199 GPa, M(110) = 335 GPa and M(111) = 340 GPa, respectively. The M values indicated that the preferred orientation will be MgO(200) due to the minimum energy configuration when the lattice strain was large. It was confirmed by the XRD results in our experiments.

A comparison study between atomic and ionic nitrogen doped carbon films prepared by ion beam assisted cathode arc deposition at various pulse frequencies

A comparison study of microstructure and bonds composition of carbon nitride (CNx) films fabricated at atomic and ionic nitrogen source by pulse cathode arc method was presented. The relative fractions of CN/CC bonds, Nsp3C/Nsp2C and graphite-like/pyridine-like N bonding configurations in the CN films were evaluated by combining C1s and N1s X-ray photoelectron spectroscopy with the hardness and optical band gap measurement. The dependence of microstructure (quantity, size and disordering degree of Csp2 clusters) of CNx films on the nitrogen source and pulse frequency was determined by Raman spectroscopy. Films with high atomic ratio of nitrogen/carbon (0.17) and high hardness were produced at ionic nitrogen source and low pulse frequency. The results showed that ionic nitrogen source facilitated the formation of CN bonds and Nsp2C bonding configurations (mainly in graphite-like N form). Moreover presenting an optimum pulse frequency (∼10Hz) leaded to the most nitrogen coordinated with sp3-C and the highest ratio of CN/CC bonds in the CNx films. An equilibrium action mechanism might exist between the quantity and energy of carbon and nitrogen ions/atoms, giving more nitrogen-incorporated carbon materials. These allow us to obtain the high content of NCsp3 bonding and expected bonding structure by optimizing pulse frequency and nitrogen source.

Zno Nanorod Synthesis via Controlled ZnO Seed Layer by Filtered Pulse Cathodic Vacuum Arc: Luminescence Enhancement

A simple synthesis route to high-quality ZnO nanorod is reported, utilizing ZnO thin films grown by Filtered Pulse Cathodic Vacuum Arc (FPCVA) deposition as seed layers and continuous growth by hydrothermal method. Depending upon the FPCVA deposited conditions, implanted voltages, thickness and annealing temperature of ZnO seed layer, the surface morphology of the ZnO nanorod on ZnO film was noticeably different. The average diameters of the nanorod on Al substrates varied from about 131.99 ± 23.87 to 418.17 ±75.50 nm. The grown ZnO nanorod showed a high crystallinity with energy gap of 3.37 eV and low defect density confirmed by UV/VIS Spectrometer and photoluminescence spectrum (PL). Large-area growth, quasi-aligned and high quality indicates that the ZnO nanorods produced have potential application in field emission and optoelectronic devices.

Chemical Bonding in Composite SiNx/Diamond-Like Carbon Films Prepared by Filter Cathodic Arc Deposition of Graphite Incorporated with Radio Frequency Sputtering of Silicon Nitride

SiNx and diamond-like carbon (DLC) films were prepared simultaneously on Si substrates by the RF magnetron sputtering of a silicon nitride (Si3N4) target and the filtered cathodic arc (FCA) deposition of graphite, respectively. The RF power was fixed at 100 W, while the arc current of graphite for the FCA deposition was varied from 20 to 80 A. The structure of composite SiNx/DLC films was investigated by Raman spectroscopy. The chemical composition and chemical state of the films were analyzed by X-ray photoelectron spectroscopy (XPS). Results revealed that the atomic concentration of carbon (C) increased, while those of silicon (Si) and nitrogen (N) decreased with increasing arc current. In addition, the sp3 content in the composite films was found to increase with the arc current. This result indicates that the structure and property of the composite films can be controlled according to their required applications by varying the arc current.

The multilayered structure of ultrathin amorphous carbon films synthesized by filtered cathodic vacuum arc deposition

Abstract

Electrochemical promotion of Pt nanoparticles dispersed on a diamond-like carbon matrix: A novel electrocatalytic system for H2 production

This study reports for the first time in the literature that the electrochemical promotion (EPOC) of Pt nanoparticles (of around 3nm) dispersed on a diamond-like carbon (DLC) matrix. A novel Pt-DLC catalyst film has been prepared by the technique of cathodic arc deposition onto a K–βAl2O3 solid electrolyte support. The catalyst film has been characterized and tested under EPOC conditions in H2 production from methanol via partial oxidation (POM) and steam reforming (SRM). After a temperature-programmed pretreatment, the Pt-DLC film achieved a suitable electrical conductivity due to the transition of the sp3-hybridized carbon form into a more graphitic structure (sp2-hybridized) as supported by different characterization measurements such as STEM and EELS. Under EPOC conditions, the H2 production rates were increased 2.5 and 3.4 times under optimal promoter coverage for POM and SRM, respectively. In addition, under POM conditions, two different electropromotional states were achieved at two different potentials attributed to the formation of different kinds of promoter phases, as confirmed by cyclic voltammetry. Finally, a comparison of the Pt-DLC catalyst film vs. a pure dense Pt layer prepared by the same technique demonstrated the higher activity of the former, due to the lower size of the Pt nanoparticles supported on the DLC matrix.