Combined Magnetron Sputtering Research Articles

Industrial scale 10 μm W coating of CFC tiles for ITER-like Wall Project at JET

As a result of the R&D phase of the ITER-like Wall Project, combined magnetron sputtering and ion implantation (CMSII) technique was selected for 10 μm W coating of approx. 1000 CFC tiles for the new JET first wall. This technique involves simultaneous magnetron sputtering and high energy ion bombardment. A high voltage pulse discharge is superposed over the magnetron deposition and by this way positive ions are accelerated, bombarding initially the substrate and then the coating itself during its growth. Based on this method, industrial equipment with a deposition chamber of Φ800 mm × 750 mm and 24 magnetrons was designed, manufactured and commissioned. The coating productivity is about 1 m 2/week. Tungsten coatings with a thickness of up to 17 μm and multilayer structures Mo/W/Mo/W with a thickness of ∼25 μm were produced and successfully tested at 100 pulses of 16.5 MW/m 2 for 1.5 s.

Oxidation performance of nano-scale multilayer coatings on γ-TiAl

There is a major drive to introduce γ-TiAl into gas turbine engines in order to reduce weight. However, this will require the development of coatings that protect against oxidation at high temperature, but do not adversely affect the mechanical properties. This work reports the high temperature degradation mechanisms of a nanoscale CrAlYN/CrN multilayer coating deposited on γ-TiAl(8Nb) by a combined high power impulse magnetron sputtering / unbalanced magnetron sputtering. Detailed TEM/STEM of FIB prepared specimens from isothermal static oxidation tests at 850°C for up to 1030 hours is presented. The evolution of the complex oxide structure and the implications for future coating development is discussed.

Fabrication and optical characterization of vanadium oxide nano-particulates thin film

We have succeeded to fabricate the thin films (350 nm in total thickness) consisting of semiconducting Vanadium-oxide (VO0.9+x (0.30≦x < 0.37)) nano-particles with 3.47 nm in averaged diameter by using the combined magnetron sputtering and gas aggregation methods. The optical band gap of the film is evaluated as 3.88 eV under the ad hoc assumption of direct allowed optical transition mode by spectroscopic ellipsometry. This value is expanded by 0.18 eV comparing with the estimated VO bulk value. The widening of band gap might be due to the lattice strain and/or the quantum confinement effect of the composed nano-particles.

High Temperature Resistant Coatings Deposited by Combined Magnetron Sputtering and Ion Implantation

Hard coatings based on the multiphase W-Ti-Si-C system have been obtained by combined magnetron sputtering and ion implantation process (CMSII). The coatings have been produced from complex targets having a variable SiC content (5 and 10 wt.-%). Their characterization included chemical and structural analysis by X-ray diffraction (XRD), and glow discharge optical emission spectrometry (GDOES), scanning electron microscopy (SEM) investigation, and microhardness measurements. The coating produced from a target with 5% SiC showed a multiphase structure consisting of W2C, W3C, and WC1 − x phases, whereas the coatings produced from target with 10% SiC revealed a multiphase structure of (W,Ti)C1 − x. The microhardness of the coatings was in the range of 2 250–3 500 HV 0.05. The layers were subjected to oxidation tests performed by heating in air at temperatures up to 920 °C. The microhardness evolution after each cycle of heating was studied.

Tungsten coatings deposited on CFC tiles by the combined magnetron sputtering and ion implantation technique

Combined magnetron sputtering and ion implantation (CMSII) is a deposition technique involving simultaneous magnetron sputtering and high energy ion bombardment of the coating during its growth. A high voltage pulse discharge (U=40 kV, τ=20 μs, f=25 Hz) is superposed over the magnetron deposition and in this way, positive ions are accelerated to the components to be coated, bombarding initially the substrate and then the coating itself. In the framework of the ITER-like wall project this method was applied to produce nanostructured W coatings on the carbon fibre composite (CFC) substrate. These coatings have been characterized in terms of adhesion, thickness, structure and resistance to high thermal loads (up to 23.5 MW m−2). Based on the results of these tests, which are presented in this paper, CMSII technology was selected for coating about 1100 tiles with a 10 μm tungsten layer for the JET first wall and divertor.

Droplet-free TiC nanocrystal-containing diamond-like carbon coatings deposited by combined cathodic arc MF magnetron sputtering

Droplet-free TiC-containing diamond-like carbon (DLC) nanocomposite coatings were deposited by using a combined cathodic arc middle-frequency magnetron sputtering system using C 2H 2 as working gas. X-ray photoelectron spectroscopy and transmission electron microscopy showed that with increasing flow rate of C 2H 2, the structure of nanocomposite coatings changed from TiC nanograin-containing to graphite nanograin-containing DLC. Wear experiment showed that the friction coefficient of TiC–DLC nanocomposite coatings decreased with increasing C 2H 2. A low friction coefficient of 0.07 was obtained at 480 sccm C 2H 2.

Tailored stoichiometries of silicon carbonitride thin films prepared by combined radio frequency magnetron sputtering and ion beam synthesis

Homogenous Si–C–N films of 120 nm thickness have been successfully fabricated by means of rf magnetron sputtering combined with ion implantation. These means are capable of producing various tailored stoichiometries of so far unequaled nitrogen concentration and high purity (O&amp;lt;0.2at.%, H&amp;lt;0.5at.%). The achieved compounds Si2CN4,SiCN2, and SiC2N2.2 consist of SiN4 tetrahedron layers interconnected by carbodiimid bridges. Stoichiometry, chemical binding states, and homogeneity of these layers as well as the reproducibility have been investigated by means of x-ray photoelectron spectroscopy, Fourier transform infrared, non-Rutherford back scattering spectroscopy, and resonant nuclear reaction analyses. Furthermore, sputter induced effects on the Si–C–N system during surface analytical characterization using Ar+ ions at 250 and 3250 eV for sputter cleaning have been studied carefully.

Effect of deposition condition on residual stress of iron nitride thin films prepared by magnetron sputtering and ion implantation

The surface roughness and residual stress development in Fe–N thin films prepared by compound technology—combining magnetron sputtering with plasma based ion implantation were investigated by means of atomic force microscope and synchrotron radiation. The results indicate that the grain size of the thin film increases with the increasing of nitrogen ion implantation time, and the state of residual stress is related closely to the formation mechanism of thin films. With the nitrogen ion implantation time increasing, the residual stress of the thin film changes into tensile stress from initial compressive stress, and the tensile stress decreases with the further increasing of ion implantation time.

Development of a hybrid coating process for deposition of diamond-like carbon films on microdrills

A hybrid physical vapor deposition-electron cyclotron resonance-chemical vapor deposition (PVD-ECRCVD) coating system has been developed and used to deposit a Ti/TiN/TiCN/DLC multilayer coating on the microdrills. In order to improve the adhesion strength of the DLC films, functionally graded Ti/TiN/TiCN supporting multilayers were pre-deposited initially on the microdrill by PVD with high rate coating sources based on a combined arc evaporation and magnetron sputtering process. The Ti/TiN/TiCN/DLC multilayer coating was completed in one deposition cycle batch. The drilled hole quality was evaluated by the nail heading (the cross section of a nail with a conical head) and surface roughness in the hole wall, and the microdrilling performance measured in terms of printed circuit board (PCB) production was investigated. Functionally, in adopting a microdrill coated with the DLC film, the inspected drilled hole quality was found to be superior than that of uncoated ones, and the drilling lifetime was significantly improved about 2.5 times.

In situ investigation of the internal stress within the nc-Ti2N/nc-TiN nanocomposite coatings produced by a combined magnetron sputtering and ion implantation method

The structure, thickness and adhesion to the substrate of the hard coatings used for protection against wear and corrosion are very important characteristics and they are strongly dependent on the internal stress induced into the coating during its growth. Development of a new class of coatings with a hardness of 2500–4500 HV0.1 and a thickness of 10–50 μm might increase significantly the application area of PVD coating in hydraulics, automotive, forming and even cutting tools. An ion assisted deposition method that combines magnetron sputtering and ion implantation (CMSII) as simultaneous processes has been used to produce nc-Ti2N/nc-TiN nanocomposite layers with such properties.In this paper, the cantilever method was used for in situ monitoring of the internal stress during the coating deposition. Generally, the internal stress produced by CMSII method is about half of that produced by magnetron sputtering without ion implantation. The structure of these coatings were analyzed by means of TEM. The adhesion and fracture properties of the coatings were analyzed by a mini version of a tensile test.

Sliding friction and wear properties of CN X/TiN composite films

A combined dc magnetron sputtering and multi-arc deposition system was used to grow CN X /TiN composite films on a high-speed-steel (HSS) substrate. The thickness of these films is about 3 μm, the hardness of the coating exceeds 50 GPa. The sliding friction properties were studied by ball-on-disc tests under different loads and speeds. The wear mode of the films was observed and analyzed. There exist spallation, abrasion and micro-ploughing wear modes under different loads. The critical load value was theoretically determined and tested to be 55 N. The results show that the alternating films have good wear resistance under heavy load and high speed.

Synthesis of ZrO 2/Y 2O 3 by combined arc and magnetron sputtering technique

Preparation of yttria-stabilized zirconia (YSZ) films by combined reactive arc evaporation and magnetron sputtering was investigated in this work. At first, the dependencies of the film deposition rate on oxygen partial pressure, arc discharge current and magnetron discharge power were measured. After complete analysis of the process of arc-magnetron deposition, the YSZ thin films were deposited on silicon, on the alloy-600 and on the ZrO 2 ceramic substrates at a substrate temperature of 400 °C. The structure and refractive index of films were investigated by X-ray diffraction and ellipsometry, respectively.

Synthesis of ZrO2/Y2O3 by combined arc and magnetron sputtering technique

Synthesis of ZrO2/Y2O3 by combined arc and magnetron sputtering technique

Combined magnetron sputtering and ECR-CVD deposition of diamond-like carbon films

A novel hybrid technique for diamond-like carbon (DLC) film deposition has been developed, which combines the electron cyclotron resonance microwave plasma discharge of C 2H 2 and metallic magnetron sputtering. In this paper we report our study of this method. The effects of negative bias voltage and hydrocarbon flow rate for the deposition of a-C:H films on high-speed steel were examined by Raman spectra and their hardness was investigated by the Rockwell method. The Raman spectra show that at different hydrocarbon flow rates, the variation of the G line peak and width, and the integrated intensity ratio I D/ I G of DLC and graphic, correlate well with the film hardness. Consequently, we suggest a deposition mechanism of DLC for this combined method.

Deposition of anti-bacterial silver coatings on polymeric substrates

A low temperature (70°C) magnetron deposition process has been developed for the deposition of silver coatings on thermally sensitive polymeric substrates. This low temperature deposition was achieved by combining magnetron sputtering with a neutral atom beam (Saddle Field) plasma source. A range of polymer sheet and tube substrates was coated with silver thicknesses in the range 5–50 nm. The bacterial adhesion and bactericidal effects of the coated polymers was assessed using Staphylococcus epidermidis and the cytotoxicity using fibroblast cells. Up to a 3 log reduction in bacterial adhesion was achieved for silver coatings on polyurethane, which did not exhibit cytotoxicity.

Titanium containing amorphous hydrogenated carbon films (a-C : H/Ti): surface analysis and evaluation of cellular reactions using bone marrow cell cultures in vitro

Amorphous hydrogenated carbon (a-C : H) coatings, also called diamond-like carbon (DLC), have many properties required for a protective coating material in biomedical applications. The purpose of this study is to evaluate a new surface coating for bone-related implants by combining the hardness and inertness of a-C : H films with the biological acceptance of titanium. For this purpose, different amounts of titanium were incorporated into a-C : H films by a combined radio frequency (rf) and magnetron sputtering set-up. The X-ray photoelectron spectroscopy (XPS) of air-exposed a-C : H/titanium (a-C : H/Ti) films revealed that the films were composed of TiO 2 and TiC embedded in and connected to an a-C : H matrix. Cell culture tests using primary adult rat bone marrow cell cultures (BMC) were performed to determine effects on cell number and on osteoblast and osteoclast differentiation. By adding titanium to the carbon matrix, cellular reactions such as increased proliferation and reduced osteoclast-like cell activity could be obtained, while these reactions were not seen on pure a-C : H films and on glass control samples. In summary, a-C : H/Ti could be a valuable coating for bone implants, by supporting bone cell proliferation while reducing osteoclast-like cell activation.

Investigation of The Oxidation Behaviour of A TiAlCrYN Pvd Hard Coating

AbstractFor dry high speed cutting the oxidation resistance of the protective hard coating of the cutting tool surface is very important. Therefore the effects of heat treatment on a TiAlN based hard coating deposited by the combined cathodic arc unbalanced magnetron sputtering technique have been studied using cross sectional transmission electron microscopy (XTEM) and energy dispersive X-ray analysis (EDX). The combination of these analytical techniques revealed the diffusion paths and preferences in diffusion of various coating and substrate elements in a physical vapour deposited (PVD) type coating after heat treatment. The structure comprises a ~2 µm thick TiAlCrYN coating on top of a 0.25 µm thick TiAlCrN base layer deposited on a stainless steel substrate. In the as-deposited sample Y was distributed in a fine layered structure (1.7 nm) throughout the coating. The coating was heat treated at temperatures between 600 °C and 900 °C in air for 10 hrs duration. With increasing temperature the microstructure changed gradually from interrupted columnar growth to a fully columnar structure at 900 °C as observed with XTEM. EDX analysis after heat treatment at 700 °C showed the presence of substrate elements Fe and Cr mainly at column boundaries in the base layer. In contrast no evidence of substrate elements could be observed in the TiAlCrYN coating, thus showing a sharp change in elemental composition concerning Cr and Fe between base layer and coating. This indicates that Y segregation in the TiAlCrYN coating along column boundaries inhibited column boundary diffusion of the substrate elements Cr and Fe. Energy dispersive X-ray distribution maps recorded after 800 °C annealing showed distinct segregation of Y along the column boundaries. The substrate elements, Fe and Cr, were observed through the coating along column boundaries up to 0.95 µm from the base layer/coating interface. After heat treatment at 900 °C the substrate elements had diffused from the substrate/coating interface to the coating surface. Y out-diffused, too and was concentrated adjacent to TiO2 crystals in the oxide layer.

Tailored a-C:H coatings by nanostructuring and alloying

Abstract The different properties of a-C:H can be tuned, either by alloying additional elements into the amorphous a-C:H or by building multilayer structures composed of two different types of a-C:H. This allows the design of optimized coatings for a wide range of applications. Multilayered a-C:H films, composed of a 60 nm Si-a-C:H adhesion layer and 300 nm multilayer structure have been deposited by a periodical variation of the sample self-bias voltage during deposition. The single layer thickness has been varied from 4 to 20 nm. The wear rate (determined by pin-on-disk measurement against a steel ball) of multilayer structures having a single layer thickness in the range of 12–14 nm, showed a drastic decrease by one decade down to 4×10 −18 m 3 Nm −1 , compared to the multilayer systems composed of thicker or thinner single layers. Amorphous hydrogenated carbon films containing titanium in different concentrations (a-C:H/Ti) were deposited by a combined RF-PACVD and DC magnetron sputtering process. The titanium content in the carbon matrix caused cellular reactions of bone marrow cells (BMC) like enhanced cell proliferation together with a reduced osteoclast cell activity. This could make a-C:H/Ti a valuable hard coating for bone implants, by enhancing bone ingrowth through osteoblast differentiation while reducing bone resorption through osteoclast inhibition.

Stress reduction in boron carbonitride films by ion energy-modulated multilayers

A multilayer concept for boron carbonitride films has been developed with optimization by stepwise graduation of the substrate bias. For this purpose, multilayers with a varying number of layers and with different single layer thicknesses were deposited by reactive magnetron sputtering in combination with ion bombardment. The energy of the ions was varied systematically. Film deposition was carried out in an argon/nitrogen gas mixture at a gas pressure of 0.35 Pa and a constant r.f. power of 400 W. During deposition, the substrates were cooled to a temperature below 100°C. The films produced were investigated by means of AES, XRD and TEM. The film properties and the film/substrate composite were characterized using different mechanical test methods. In particular, the film stress was determined by the bending of thin silicon substrates (0.18 mm). According to the AES measurements, the carbon concentration of the films amounted to about 22.5 at.%, with lower values being measured at the higher ion energies. The boron/nitrogen ratio was constant at 1.4 in all films. Graded multilayers were found to have stresses that were far below the theoretical values obtained by mere superpositioning of the stresses of deposited monolayers. This is attributed to the influence of the interface in the layer composite. A 2 μm thick multilayer consisting of seven single layers has a hardness of 25 GPa, a residual stress of 1.67 GPa (instead of 5.3 GPa) and a good adhesion with critical loads of failure of 44 N, as determined in a scratch test.

Variation of carbon concentration, ion energy, and ion current density of magnetron-sputtered boron carbonitride films

Diamond, cubic boron nitride and also ternary materials consisting of boron, carbon and nitrogen exhibit an extraordinary combination of extreme mechanical and physical properties due to their bonding characteristics and crystal structure. This results in a high application potential in protective and functional layers. Taking into account the special properties of these phases, the compositions inside the B=C=N concentration triangle are of particular interest, as novel superhard phases are expected to occur. In this work, boron carbonitride films of variable compositions were produced by means of reactive radio frequency (r.f.) magnetron sputtering in combination with ion bombardment. Examination up to now has revealed carbon concentrations between 16 and 27 at.% and a boron/nitrogen ratio varying between 1.08 and 1.26. For a carbon concentration of 12 at.%, the ion energy was varied between 125 and 300 eV at a constant ratio of ions to film-forming particles, Φion/ΦBCN. Peak analyses of the differentiated Auger spectra gave no indication of any generation of B=C bonds. The contents of the h-BN phase and c-BN phase as well as the threshold conditions and optimum conditions for c-BN formation were investigated for 8 energy variations at 18 values of Φion/ΦBCN between 0.1 and 0.5. IR spectroscopy showed that the maximum fraction of sp3-hybrid BN bonds reached approximately 61% at an ion energy of 200 eV and an ion current density of 0.5 mA cm−2. The film properties can be strongly influenced by the flux ratio of ions to film-forming particles, Φion/ΦBCN, and by the ion energy. Generally, the effect on the film properties by increasing the flux ratio Φion/ΦBCN or by decreasing the ion energy is often the same. This statement is discussed theoretically.