Arc Sputtering Research Articles

Лазерное и электронно-лучевое упрочнение металлов с наноуглеродным покрытием

The results of experiments on modifying metal surface by applying nanocarbon coating followed by laser or electron beam treatment are generalized. Soot produced as a result of electric arc sputtering of graphite electrodes followed by extraction of fullerenes, graphene oxide thermally reduced at different temperatures, and С60 fullerene were used as nanocarbon coating. An impulse laser with a wavelength of 1.064 μm, impulse energy at a level of 10 J, and impulse duration around a few milliseconds was used as a source of high-energy irradiation. An accelerator providing electron energy of 60 keV and a stationary beam current up to 250 mA was used as an electron beam source. The accomplished experiments point to a considerable (up to 8 times) increase in the microhardness of the treated steel surface which is accompanied by a decrease of the friction coefficient by several tens percent. It has also been found that the microhardness of the treated surface is a non-monotonic function on the laser or electron beam irradiation energy.

Composition, Structure and Mechanical Properties of CrAlC Films Deposited by Arc Sputtering Technique

A focus point in this work was the research of the influence of deposition condition on properties of CrAlC films. CrAlC films were deposited by arc sputtering technique using arc sputtering of Cr-Al target and pulse arc sputtering of graphite target at different frequency. The multilayer [(CrAlC)+(a-C)]ncoatings were also obtained and investigated. Multilayer [(CrAlC)+(a-C)]nwere deposited with a systematic alternation of the pair [(CrAlC)+(a-C)], where a-C is the amorphous carbon layer. The structure, mechanical properties and fracture toughness of CrAlC films depend on pulse frequencies of the graphite sputtering. With increasing pulse frequency, the film structure changes from uniformly amorphous to amorphous with nanograins, the hardness of the films increases, the critical load of crack formation and film peeling tend to decrease. It is shown that a decrease in the thickness of the layers in [(CrAlC)+(a-C)]nleads to an increase in the crack resistance.

Hybrid Ti-MoS2 Coatings for Dry Machining of Aluminium Alloys

Combinatorial deposition, comprising filtered cathodic vacuum arc (FCVA) and physical vapor deposition (PVD) magnetron sputtering is employed to deposit molybdenum disulphide (MoS2) and titanium (Ti) thin films onto TiB2-coated tool inserts specifically designed for the dry machining of aluminium alloys. Titanium is deposited by FCVA while MoS2 is magnetron sputtered. The deposition set up allows several compositions of Ti-MoS2 to be deposited simultaneously, with Ti content ranging between 5 and 96 at. %, and their machining performances to be evaluated. Milling took place using a CNC Vertical Machining Center at a 877 mm/min feed rate. The effect of different coating compositional ratios on the degree of aluminium sticking when a milling insert is used to face mill an Al alloy (SAE 6061) was investigated using a combination of energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) analysis. XPS studies suggest that the greater degree of Al sticking on the rake face of the inserts is due to the formation of greater amounts of non-protective Ti-O phases. EDX mapping of the milling inserts after machining reveal that a Ti:MoS2 ratio of around 0.39 prevents Al from sticking to the tool edges. Since we prevent Al from sticking to the tool surface, the resultant machined surface finish is improved thus validating the machining performance of TiB2-coated tools using optimum compositions of Ti:MoS2 thin film coatings.

Copper Oxide of Plasma-Chemical Synthesis for Doping Superconducting Materials

Properties of nanodispersed powder copper oxide, synthesized during arc sputtering of copper in a gas mixture of low pressure oxygen, were studied. It was shown that the particles possess nanometer size and narrow size distribution. The issue of reduction, recrystallization and sintering of nanodispersed powder were discussed.

Cathodic arc sputtering of functional titanium oxide thin films, demonstrating resistive switching

The formation of thin films of the different stable and metastable titanium oxide phases is demonstrated by cathode arc sputtering of a titanium target in an oxygen atmosphere. We also show that sputtering of titanium in vacuum yields the formation of titanium silicides on the silicon substrate. The crystal structure of the produced samples was investigated using Raman spectroscopy and X-ray diffraction. We conclude that cathode arc sputtering is a flexible method suitable for producing the functional films for electronic applications. The functionality is verified by the memory effect demonstration, based on the resistive switching in the titanium oxide thin film structure.

The composition, structure and surface properties of the titanium-carbon coatings prepared by PVD technique

Amorphous carbon (a-C) and titanium-carbon nanocomposite TiCx/a-C coatings were deposited using the PVD technique. TiCx/a-C were deposited by simultaneous sputtering of graphite and titanium targets using arc pulse (at the frequency of 3 to 25Hz) and arc sputtering respectively. The composition, chemical structure and electrical properties of the surface have been studied by energy-dispersive X-ray spectroscopy, Raman spectroscopy and Kelvin probe force microscopy (KPFM). The increase in graphite sputtering arc pulse frequency is accompanied by the growth of carbon content in TiCx/a-C from 38 to 82at.% and by the change of phase composition. The incorporation of the Ti+ ions into the plasma flow of C+ increases the number of sp2 bonds in carbon matrix of TiCx/a-C, as compared to a-C deposited at the same frequency. The maps of contact potential difference (CPD) distribution over the surface of a-C and TiCx/a-C obtained by KPFM were used to calculate the root-mean-square (RMS) values of CPD. In a-C RMS of CPD decreases with scale up of arc pulse frequency. In TiCx/a-C RMS of CPD nonlinear depends on the carbon content and reaches maximum at CC=44at.%. It has been suggested, that at the contacts of different phases an interface thin layer is formed. The electronic properties of this layer differ from the electronic properties of the bulk phases of nanocomposite. The increase in volume fraction of interface component leads to the drop of RMS of CPD.

Adsorption of polar molecules on diamond-like carbon films with different trapped charge densities

This work investigates the effect of trapped charge densities present in diamond-like carbon films (DLC) on adsorption of polar molecules on the film surface. Hydrogen-free and hydrogenated DLC films with different hydrogen/carbon contents were produced using filtered-cathodic arc sputtering (FCA-sputtering) and radio-frequency plasma enhanced chemical vapor deposition (RF-PECVD) techniques, respectively. After treating the as-prepared films in a dilute solution of dipropylene glycol monomethyl ether, adsorption of such molecules was found throughout the film surface. Capacitance–voltage (C–V) measurements have shown that the DLC films with lower hydrogen/carbon content inherently have larger trapped charge accumulations within their structures. A charge density of 1600nC/cm2 was measured in a DLC film with a lower hydrogen/carbon content (produced from C2H4 and Ar precursors), while a much smaller charge density of 64nC/cm2 was measured in a DLC film with a higher hydrogen/carbon content (produced from 10% CH4 and 90% H2 precursors). A correlation between charge densities and the degree of polar molecule adsorption was observed. Films with higher charge densities appeared to be more prone to polar molecule adsorption.

Microstructure and mechanical properties of Cr–V–C–N films

Quaternary Cr–V–C–N films were deposited on Si wafers through a hybrid system of arc ion plating and sputtering techniques in an Ar/N2/CH4 gaseous mixture. In this work, the effects of vanadium on the microstructural evolution, mechanical properties and friction mechanism of Cr–V–C–N films were investigated. The results showed that quaternary Cr–V–C–N films consisted of nanosized crystallites of (Cr,V)(C,N) and amorphous VCN phases. The Cr–10·4 at-%V–C–N film possessed the higher hardness value of 34 GPa, compared to the 27 GPa of a Cr(C,N) film. Additionally, the friction coefficients of the Cr–V–C–N films were reduced from 0·38 for the Cr–C–N film to 0·27 for the Cr–10·4 at-%V—C–N film. Atomic force microscopy (AFM) and Auger electron spectroscopy (AES) analyses also revealed that the amorphous phase VCN phases played a role in reducing the friction coefficients of the films. The a-VCN phase (vanadium rich) was believed to cause a tribochemical reaction with ambient air during the wear process.

XPS study of TiN films formed by the electric arc technique

The phase composition of the 3 nm surface layer of Ti and TiN films is studied by X-ray photo-electron spectroscopy. The films are deposited by the electric arc sputtering of a titanium cathode in a nitrogen atmosphere under a magnetic field. It is shown that the film surface layer contains TiN, TiN x , TiO x , TiO2, and TiN x O y phases. A mechanism explaining the formation of titanium nitride films is proposed.

Influence of pressure and hydrocarbons on carbide formation in the plasma synthesis of TiC nanoparticles

We examine the influence of pressure and gas mixture composition on the preparation of nanomaterials via vacuum arc sputtering of titanium cathodes in carbon-containing media. The formation of carbide phases in various gaseous atmospheres is accompanied by the formation of the low-temperature phase α-Ti (hcp lattice), characteristic of pure titanium. Carbide formation in the plasma synthesis of TiC nanoparticles is determined by the C/H ratio in the molecules of the hydrocarbons used. To raise the yield of carbon-rich carbide phases and reduce the percentage of the residual metal in the resulting nanopowders, it is necessary to use hydrocarbons with a large C/H ratio, for example, benzene and acetylene.

Synthesis and characterization of zirconium nitride coatings by cathodic arc sputtering technique

Abstract Polycrystalline zirconium nitride films (560 nm) were deposited on stainless steel (SS-316) substrates using the multi-target cathodic arc sputtering technique. Deposition was carried out under N2 reactive atmosphere (4 × 10−3 mbar) at two different temperatures, 150 and 200 °C. X-ray diffraction studies show that reflections from planes changed from (111) to (200) for deposition temperatures of 150 °C and 200 °C, respectively. Films deposited at 150 °C and 200 °C bear a critical load of 6.4 N and 6.8 N respectively, showing better adherence at higher temperature. This may be the result of film–substrate diffusion at the interface.

Effect of thermal annealing on the properties of a C/Ni heterostructure

The results of experimental investigation of the effect of a nickel catalyst on the structural features of carbon films deposited by the arc sputtering of graphite are represented. It is shown that the interaction of the carbon film with the nickel film at a temperature of 1100°C results in the formation of graphitic nanostructures.

Production of carbon films by the electric arc sputtering of graphite in a magnetic field

The results of experimental investigation of the effect of a magnetic field on the structural-morphological features of carbon films deposited by the electric arc sputtering of graphite are presented. It is found that the action of a magnetic field on the plasma flux causes the formation of a practically smooth amorphous film. However, the magnetic field prevents the formation of graphitic nanoclusters (∼4 wt %) in the film, the presence of which is the cause of the field emission of electrons at a low threshold field strength of ∼7.5 V/μm.

On the structure and properties of a material deposited from arc discharge plasma near the cathode and onto vacuum-chamber walls

The structure and composition of a material (composite) deposited onto vacuum-chamber walls from arc discharge plasma during the crystallization of cathode spot products in electric and magnetic fields is studied by the methods of electron microscopy and energy dispersive analysis. The regular character of the inclination of the columnar structure of films growing from a separated droplet fraction of the plasma near the cathode assembly during arc sputtering is established. It is shown that the magnetic field of the focusing coil has a more noticeable effect on the particle trajectory near the cathode under the used operating modes of the cathode assembly as compared to the interelectrode potential.

Development of a hybrid process of obtaining wear-resistant coatings based on ion-plasma arc sputtering and magnetron sputtering

This work is devoted to the development of a new hybrid method of deposition of coatings based on ion-plasma arc sputtering and magnetron sputtering. The objects of investigation were samples of coatings of the Ti-Al-N system on the VK-6 hard-alloy plates obtained by three different methods, namely, ion-plasma sputtering, magnetron sputtering, and hybrid sputtering. Deposition processes were performed under the rarefaction of 1.3 × 10−3 Pa at a substrate temperature of 550–600°C. A VT-5 alloy of the composition Ti-Al (6 at %) was used as the sputtered material. The phase and elemental compositions of the coatings, their mechanical properties (microhardness and the Young modulus), and adhesion strength were studied. All samples were tested under the conditions of continuous cutting. The results of investigations showed that the coating obtained by the hybrid method possesses a complex of positive properties of the ion-plasma and magnetron coatings, specifically, a high adhesion strength along with the uniformity of the composition and structure, which explains its increased durability.

Structure and properties of Ti-Si-N coatings synthesized by combining cathode arc and middle-frequency magnetron sputtering

Ti-Si-N composite coatings were synthesized on a novel combining cathode and middle-frequency magnetron sputtering system, designed on an industrial scale. Ti was produced from the arc target and Si from magnetron target during deposition. The influences of negative bias voltage and Si content on the hardness and microstructure of the coatings were investigated. The composite coatings prepared under optimized conditions were characterized to be nc-TiN/a-Si3N4 structure with grain sizes of TiN ranging from 8-15 nm and exhibited a high hardness of 40 GPa. The enhancement of the hardness is suggested to be caused by the nanograin-amorphous structure effects.

Ultrasoft X-ray spectroscopy with variation of the electron excitation energy as a method for analyzing thin films and solid/solid interfaces

The application of ultrasoft X-ray spectroscopy with variation of the electron excitation energy for phase analysis of thin films and phase reactions at solid/solid interfaces is considered. CNx nanocondensatess obtained by pulsed arc sputtering of graphite in the presence of nitrogen, silicon implanted with hydrogen ions, and Fe-Co silicides fabricated by ion-beam synthesis have been studied.

X-ray emission and Raman spectroscopy of CN0 ≤ x ≤ 0.5 nanocondensates prepared by pulsed arc sputtering of graphite in the presence of nitrogen

The nanocomposite structure of the DLC-C2N condensate is confirmed by analyzing the x-ray emission spectra of the CN0 ≤ x ≤ 0.5 films prepared by pulsed arc sputtering of graphite in the presence of nitrogen.

Comparative Studies on Microstructure and Mechanical Properties of CrN, Cr-Mo-N and Cr-Si-N Coatings

CrN-based multi-component coatings were deposited by a hybrid coating system combining the arc ion plating (AIP) and sputtering technique. In this work, comparative studies on microstructure and mechanical properties of microhardness and wear behavior among CrN, Cr-Mo- N, Cr-Si-N coatings were systematically conducted. Adding Mo and Si atoms into CrN coatings had important effects on microstructural change and mechanical properties of CrN coatings. The maximum hardness values of Cr-Mo-N and Cr-Si-N coatings were the same value of 34GPa, These values were much enhanced compared with 18GPa of CrN coating. The average friction coefficient of CrN-based coatings decreased to 0.37 and 0.2 with the incorporation of Mo and Si content

Mechanical properties of CN x coatings obtained by carbon arc sputtering

Internal stresses σ0, friction coefficients fand microhardness were measured in diamond-like coatings obtained by vacuum-arc sputtering of carbon target at different nitrogen pressures in a work chamber during deposition on metallic substrates. The dependence of these parameters on nitrogen concentration in coatings can be used in practical deposition of strengthening and friction coatings for improvement of their tribological properties. The correlation between mechanical properties of diamond-like and CN x coatings was established.