High Power Pulsed Magnetron Sputtering Research Articles

Deposition of rutile TiO2 films by pulsed and high power pulsed magnetron sputtering

Abstract Thin films of titanium dioxide (TiO2) are important high refractive index coatings in optical multilayer stacks. Especially interesting is the rutile crystalline phase of TiO2 films because it's refractive index in the range of 2.6…2.7 is the highest available refractive index of materials being transparent in the visible and near infrared wavelength region. Rutile TiO2 films in optical interference coatings therefore in principle allow achieving the desired optical function with a lower number of layers and a simpler design compared to alternative high index materials. However the crystalline growth of TiO2 layers usually starts with an amorphous start layer of typically 40 nm thickness before going over to an anatase or rutile crystalline structure. The amorphous start layer typically has a refractive index in the range of 2.4…2.5. This significant difference to the index of the rutile film leads to a typical gradient in the refractive index of TiO2 single layers and makes application of TiO2 films in precision optics practically difficult. The paper explores the possibilities of obtaining rutile TiO2 films right from the beginning of film growth by significantly increasing energetic ion bombardment of the growing film and adatom mobility. The influence of a variety of process parameters such as substrate temperature, deposition pressure, magnetic field strength and RF bias is investigated. The main focus of investigations was the comparison of a standard pulse process, a pulsed process with significantly increased pulse current and a pulse process in genuine high power pulsed (HiPIMS) mode. Film deposition was done by stationary sputtering using the double ring magnetron (DRM). Film characterization was carried out by XRD as well as by spectroscopic ellipsometry and photometry. Total optical losses were characterized by cavity-ring-down spectroscopy (CRD) and absorption was measured by laser induced deflection. Results show that in a rather narrow range of process parameters the desired crystalline growth of TiO2 with the rutile phase throughout the film can be obtained. This parameter set includes both the pulsed process with significantly increased pulse current and the genuine HiPIMS mode, but in all cases requires a combination with substrate heating, RF substrate bias and adapted process pressure. A significant reduction of crystallite size and scattering losses was achieved by adding a small amount of silicon dioxide (SiO2) to the film.

Peak amplitude of target current determines deposition rate loss during high power pulsed magnetron sputtering

Film growth rates during DCMS and HIPIMS sputtering in Ar are measured for ten technologically-relevant elemental target materials: Al, Si, Ti, Cr, Y, Zr, Nb, Hf, Ta, and W, spanning wide range of masses, ionization energies, and sputter yields. Surprisingly, the ratio of power-normalized HIPIMS and DCMS rates α decays exponentially with increasing peak target current density JTmax for all metals. The effect of JTmax on α is dramatic: α≈1 in the limit of lowest JTmax values tested (0.04 A/cm2) and decreases to only 0.12 with JTmax ∼3 A/cm2. With the exception of Al and Si, α(JTmax) curves overlap indicating that the debated rate loss in HIPIMS is to large extent determined by the peak amplitude of the HIPIMS target current for all tested metals. Back attraction of ionized target species is responsible for such large variation in α.

Tribocorrosion response in biological environments of multilayer TaN films deposited by HPPMS

Abstract Biomedical implant failure arises mainly from the degradation caused by tribological processes occurring in the corrosive environment the human body represents, known as tribocorrosion. The material loss and metal ion release resulting from tribocorrosion processes compromise the biocompatibility of metallic implants. The deposition of protective coatings on metallic substrates is a promising solution to overcome this problem. Pure titanium (Ti-cp) is widely used as an implant material due to its excellent corrosion resistance and high biocompatibility. However, its mechanical properties must be improved in order to ensure a longer durability. For this purpose, TaN monolayer and multilayer coatings were deposited on medical grade Ti-cp to enhance its tribocorrosion performance in simulated body fluids. TaN coatings were deposited by recently developed High Power Pulsed Magnetron Sputtering (HPPMS) technique. HPPMS enables the deposition of extremely dense coatings with superior properties compared to the ones grown by conventional sputtering. Columnar-free TaN monolayer and multilayer films were developed exhibiting corrosion resistances in the MΩ range, one order of magnitude higher than for Ti-cp. Friction coefficient of Ti-cp was reduced from 0.58 to 0.25 while wear rate was considerably decreased. The determined material loss after tribocorrosion tests for Ti-cp was 0.4 mm3. It was reduced up to 1.55 × 10− 3 mm3 by the application of best-performing TaN multilayer film.

Piezoresistive properties of diamond like carbon films containing copper

In the present study diamond like carbon films containing copper (DLC:Cu) were deposited by reactive magnetron sputtering. Direct current (DC) sputtering and high power pulsed magnetron sputtering (HIPIMS) were used. The influence of the composition and structure on piezoresistive properties of DLC:Cu films was investigated. Structure of DLC:Cu films was investigated by Raman scattering spectroscopy and transmission electron microscopy (TEM). Chemical composition of the films was studied by using energy-dispersive X-ray spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS). Particularly analysis of XPS O1s spectra revealed oxidation of Cu nanoparticles. Piezoresistive gauge factor of DLC:Cu films was in 3–6 range and decreased with the increase of copper atomic concentration. Tendency of the decrease of the gauge factor of DLC:Cu films with the increased D/G peak area ratio (decreased sp3/sp2 carbon bond ratio) was observed. It was found that resistance (R) of DLC:Cu films decreased with the increase of Cu atomic concentration by logarithmic law. It is shown that a quasilinear increase of piezoresistive gauge factor with log(R) is in good accordance with percolation theory. Temperature coefficient of resistance (TCR) of DLC:Cu films was negative and decreased with copper amount in Cu atomic concentrations ranging up to ~40%. Very low TCR values (zero TCR) were observed only for DLC:Cu films with low gauge factor that was close to the gauge factor of the metallic strain gauges. Role of some possible mechanisms: copper amount as well as Cu cluster size on the value of gauge factor is discussed.

Mechanical and tribological properties of CrN/TiN superlattice coatings deposited by a combination of arc-free deep oscillation magnetron sputtering with pulsed dc magnetron sputtering

Deep oscillation magnetron sputtering (DOMS) is an alternative high-power pulsed magnetron sputtering technique, which offers virtually arc-free depositions especially for reactive depositions of some insulating coatings under optimized pulsing conditions. CrN/TiN superlattice coatings with a modulated period (Λ) ranging from 5.7 to 10.2nm were deposited using a combination of DOMS and pulsed dc magnetron sputtering in a closed field unbalanced magnetron sputtering system. As a Λ was increased from 5.7 to 10.2nm, CrN/TiN superlattice coatings with the increased Cr/(Cr+Ti) ratio from 0.177 to 0.496 exhibited a single phase face-centered cubic structure with a strong {111} texture. Correspondingly, the hardness, the H/E* and H3/E*2 ratios showed an initial increase, followed by a decrease. The coatings at Λ=6.3nm with the Cr/(Cr+Ti) ratio of 0.294 and fine grain size of about 30nm showed the highest hardness of 36GPa, H/E* ratio of 0.093 and H3/E*2 ratio of 0.313. It also showed a mild abrasive wear with the lowest friction coefficient and specific wear rate of 0.27 and 0.5×10−6mm3N−1m−1, respectively. With increasing Λ, the friction coefficient and specific wear rate decreased and then increased. The dominant wear mechanism changed from oxidative wear to mild abrasive wear, and then to severe oxidative wear. The changes of H, H/E* and H3/E*2 ratios and adhesion of CrN/TiN superlattice coatings resulted in variation of tribological properties and wear mechanism.

Elementary surface processes during reactive magnetron sputtering of chromium

The elementary surface processes occurring on chromium targets exposed to reactive plasmas have been mimicked in beam experiments by using quantified fluxes of Ar ions (400–800 eV) and oxygen atoms and molecules. For this, quartz crystal microbalances were previously coated with Cr thin films by means of high-power pulsed magnetron sputtering. The measured growth and etching rates were fitted by flux balance equations, which provided sputter yields of around 0.05 for the compound phase and a sticking coefficient of O2 of 0.38 on the bare Cr surface. Further fitted parameters were the oxygen implantation efficiency and the density of oxidation sites at the surface. The increase in site density with a factor 4 at early phases of reactive sputtering is identified as a relevant mechanism of Cr oxidation. This ion-enhanced oxygen uptake can be attributed to Cr surface roughening and knock-on implantation of oxygen atoms deeper into the target. This work, besides providing fundamental data to control oxidation state of Cr targets, shows that the extended Berg's model constitutes a robust set of rate equations suitable to describe reactive magnetron sputtering of metals.

Application of a cohesive zone element for the prediction of damage in nano/micro coating

AbstractMany tools in production technology are nowadays coated to obtain a satisfactory lifetime and degradation resistance. Therefore, the main goal of this study is to investigate antiadhesive and wear resistant coatings made of ceramics, plastics and metals produced by High Power Pulsed Magnetron Sputtering (HPPMS) technique [1]. A cohesive zone element technique (CZ) is applied to model the interactions of the coatings and the substrate surfaces (see [2]). This goes along with the investigations of the delamination and failure behavior of the involved surfaces. To illustrate the applicability of the model, several structural simulations are performed. The developed CZ element model is capable of modeling the separation, the contact and also the irreversible reloading conditions in both normal and tangential directions [3]. The model is further developed to be applicable for different structures including different bonding behaviors, with a higher stability. The talk concludes with a detailed discussion of the numerical results of different material and interface properties. (© 2015 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Aluminum-rich HPPMS (Cr1−xAlx)N coatings deposited with different target compositions and at various pulse lengths

Target properties and pulse configuration are important factors in high power pulsed magnetron sputtering. The present work deals with analyses of the effects of the pulse length, i.e., duty cycle on the HPPMS process and on the properties of Al-rich (Cr1−xAlx)N coatings deposited with plugged targets in an industrial scale unit. The results showed that the peak power density increased from 0.32 kW/cm2 to 0.86 kW/cm2 as the pulse length decreased from ton = 200 μs to 40 μs. (Cr1−xAlx)N coatings with a high aluminum content between x = 68 at% and x = 76 at% were produced. The deposition rate reveals a constant behavior using different Al-rich targets at the same pulse length. A mixture of cubic and hexagonal (Cr1−xAlx)N phases was found for each coating. Furthermore, a finer and denser morphology as well as a smoother surface were observed at reduced pulse length compared to large pulse configuration due to the high peak current and power density. The maximum hardness of HU = 30.0 GPa and a moderate elastic modulus of EIT = 421 GPa were achieved for the (Cr0.30Al0.70)N coating deposited at a pulse length of ton = 40 μs, i.e., duty cycle of 2%.

Modulate the deposition rate through changing the combination of frequency and pulse width at constant duty cycle

Due to the large degree of ionization of the sputtered flux and high quality film fabrication, high power pulsed magnetron sputtering (HPPMS) is widely used. However, compared with DC sputtering, low deposition rate is probably the drawback of the HPPMS technique and restricts its application. In order to increase the deposition rate of HPPMS, different combinations of frequency and pulse width at a constant duty cycle were used to modulate the deposition rate of the Ti film. The results showed that wider pulse width would be more effective than increasing frequency on improving titanium deposition rate for a constant duty cycle. The pulse width also would affect the power utilization ratio. Especially for a high duty cycle of 4.8% and 5.6%, a wider pulse was favorable to make full use of power on film deposition, resulting in a higher normalized static deposition rate. Meanwhile, with increase in pulse width for a constant duty cycle, adatom mobility and the deposition rate increased, contributing to growth of crystallite size and higher surface roughness of Ti thin films.

Analysis of ion energy distribution at the substrate during a HPPMS (Cr,Al)N process using retarding field energy analyzer and energy resolved mass spectrometer

The ion energy is known to have a strong influence on the properties of coatings deposited by physical vapor deposition (PVD). Therefore, the ion energy distribution (IEDF) especially measured at the substrate side is of great interest for understanding the coating growth. In PVD coating processes the ion energy at the substrate can be adjusted by applying a negative voltage (bias) to the substrate table. In the present work, mass integrated measurements of the IEDF were carried out during a high power pulsed magnetron sputtering (HPPMS) (Cr,Al)N process using a Cr target with 20 plugs of Al within an industrial scale PVD coating unit. The HPPMS cathode was operated with different average powers (1kW, 3kW and 5kW) and pulse lengths (ton) of 40μs, 80μs and 200μs at constant frequency of 500Hz. In a first step, measurements of the IEDF using retarding field energy analyzer (RFEA) were carried out on grounded substrate table and later on using −100V substrate bias. Additionally, measurements of the IEDF were carried out using mass spectrometer (MS) exemplary to compare with the results from RFEA. By comparing the measured IEDFs some limitations of these two different measurement methods were found. The MS underestimates that the amount of high energetic ions and the RFEA measurement are influenced by the incidence angle of the ions. Besides those limitations the influence of cathode power and HPPMS pulse length on the IEDF was studied. At high peak power density, i. e. short pulse length and high average cathode power, a much greater high energetic fraction in the IEDF between 10 and 50eV was found in the results of the RFEA compared to MS results presented here. Also the effective mean ion temperature in the high energetic region of the IEDF was found to increase with increasing peak power density. Furthermore, the effective mean ion temperature was not strongly influenced using substrate bias.

Effect of the nitrogen flow rate on the microhardness and microstructure of TiN coatings deposited by high power pulsed magnetron sputtering

TiN coatings are deposited onto AISI430 stainless-steel substrates in an Ar + N2 atmosphere, under a constant total pressure of 0.5 Pa, at a variable nitrogen-flow rate of f(N2) = 0.5–10 cm3/min and magnetron-sputtering currents of Im = 10, 30, and 100 A. The dependences of the coating microhardness, macrostress, and growth rate on f(N2) and Im are obtained. Two microharndess maxima at f(N2) = 1 and 4 cm3/min and Im = 30 A are found. The maximum microhardness of the coatings reaches 32 ± 5 GPa at a maximum macrostress of 7 GPa.

Investigation on plastic behavior of HPPMS CrN, AlN and CrN/AlN-multilayer coatings using finite element simulation and nanoindentation

Abstract A comprehensive investigation of hard coatings deposited by physical vapor deposition (PVD) requires, in addition to the elastic properties, a precise knowledge of their plastic behavior. Nanoindentation is a commonly applied method to determine the hardness and the elastic modulus of PVD coatings. Determination of flow curve of PVD thin coatings using a combination of nanoindentation and finite element (FE) simulation is the subject of current research. In the presented work, nanoindentation tests with a Berkovich tip, in combination with its FEM simulation, were used to determine the plastic flow curves of CrN, AlN and CrN/AlN-multilayer coatings deposited by high power pulse magnetron sputtering (HPPMS) PVD on cemented carbide substrates. The applied FEM model was used to simulate the indentation process. The details of the FEM model and the applied experimental and analytical methods are discussed. The determination of the simulative flow curves was carried out according to the Johnson–Cook model and by finding the coefficients of the considered plastic flow model. The coefficients were determined by comparing the simulated and measured maximum forces, and additionally, by correlating the indentation imprints after nanoindentation tests in simulation and experiment. The correlation was performed by depth profiling of the indentation imprints using confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM). The plastic behavior of the studied coating systems was analyzed combining the simulated flow curves and the results of the analysis of indentation imprints. The results show a higher resistance of the nanostructured CrN/AlN-multilayer coating against plastic deformation compared to CrN and AlN. This is most likely due to the nm-sized alternating layers and the fine grained morphology of the CrN/AlN-multilayer compared to the pure coatings, which hinders the dislocation motion.

Titanium interlayer between Ti–O film on CoCrMo implant alloy for improving adhesion: Detailed XPS and TEM analysis of the interface

The stability of interface adhesion of the Ti–O film is an important factor in evaluation of the suitability of Ti–O surface modification of stents. In our previous work, Ti–O films were deposited on Ti pre-coated and virgin CoCrMo substrate by high power pulsed magnetron sputtering. A Ti interlayer that formed on the CoCrMo alloy substrate can improve the film–substrate adhesion. In order to further understand the properties of the Ti–O coating on CoCrMo with Ti interlayer, the elemental composition and chemical state of the Ti–O/Ti film were measured by X-ray photoelectron spectroscopy layer-by-layer. The microstructure and chemistry at the interface were characterized by Transmission Electron Microscopy. The results indicate that there is no delamination even though the substrate endures large deformation. The Ti interlayer significantly improves the Ti–O film adhesion, which may be ascribed to the presence of Co–Ti metal bonding in the TiO/Ti/CoCrMo system as well as strong physical bonding. Thus we find that a Ti interlayer can release shear stress generated in interface deformation and improve the deformation coordination between the Ti–O film and the CoCrMo substrate.

The structure, oxidation resistance, mechanical and tribological properties of CrTiAlN coatings

CrxTiyAlzN coatings (x+y+z=1) with low Al contents were deposited using hybrid high power impulse magnetron sputtering (HiPIMS) and pulsed dc magnetron sputtering (PDCMS). The Ti fraction (fTi=Ti/(Cr+Ti+Al)) was increased from 5 to 64% to produce coatings with different chemical compositions varied from Cr-rich to Ti-rich. The microstructure of the coatings was studied using X-ray diffraction and scanning electron microscopy. Mechanical properties of the coatings were analyzed by nanoindentation. The oxidation behavior of the coatings was evaluated in the ambient air at 900°C and 1000°C. The high temperature wear resistance of the coatings was measured using a high temperature pin-on-disc tribometer in the ambient air from 600°C to 900°C. The CrTiAlN coatings showed a (111) preferred orientation when the fTi is less than 10%. The orientation of the coatings changed from (111) to (311) as the fTi increased. The addition of a small amount of Ti (e.g., fTi=5–10%) effectively improved the mechanical properties and the wear resistance of the Cr0.66Al0.34N baseline coating. The Cr0.61Ti0.10Al0.29N coating exhibited the highest hardness of 40GPa, the lowest coefficient of friction of 0.4 and the lowest wear rate of 7×10−7mm3N−1m−1 at room temperature. The Cr0.61Ti0.10Al0.29N coating also showed excellent oxidation resistance after annealing at 1000°C and good wear resistance from 600°C to 800°C. These enhanced properties can be attributed to multiple factors including solid solution strengthening, the dense microstructure, and the strong (111) orientation. However, as the fTi increased from 20% to 64%, the oxidation resistance, mechanical properties, and wear resistance of the CrTiAlN coatings decreased.

High power pulsed magnetron sputtering: A method to increase deposition rate

High power pulsed magnetron sputtering (HPPMS) is a state-of-the-art physical vapor deposition technique with several industrial applications. One of the main disadvantages of this process is its low deposition rate. In this work, the authors report a new magnetic field configuration, which produces deposition rates twice that of conventional magnetron's dipole magnetic field configuration. Three different magnet pack configurations are discussed in this paper, and an optimized magnet pack configuration for HPPMS that leads to a higher deposition rate and nearly full-face target erosion is presented. The discussed magnetic field produced by a specially designed magnet assembly is of the same size as the conventional magnet assembly and requires no external fields. Comparison of deposition rates with different power supplies and the electron trapping efficiency in complex magnetic field arrangements are discussed.

Surface treatment of diamond-like carbon films by reactive Ar/CF4 high-power pulsed magnetron sputtering plasmas

Surface modification of diamond-like carbon films deposited by a high-power pulsed magnetron sputtering (HPPMS) of Ar was carried out by a HPPMS of Ar/CF4 mixture, changing a CF4 fraction from 2.5% to 20%. The hardness of the modified films markedly decreased from about 13 to about 3.5GPa with increasing CF4 fraction, whereas the water contact angle of the modified films increased from 68° to 109° owing to the increase in the CFx content on the film surface. C 1s spectra in X-ray photoelectron spectroscopy indicated that a graphitic structure of modified films was formed at CF4 fractions less than 5%, above which the modified films possessed a polymer-like structure.Influence of treatment time on the properties of the modified films was also investigated in the range of treatment time from 5 to 30min. The properties of the modified films did not depend on the treatment time in the range of treatment time longer than 10min, whereas the water contact angle was not sensitive to the treatment time at any treatment time.

Strategy for tuning the average charge state of metal ions incident at the growing film during HIPIMS deposition

Energy and time-dependent mass spectrometry is used to determine the relative number density of singly- and multiply-charged metal-ion fluxes incident at the substrate during high-power pulsed magnetron sputtering (HIPIMS) as a function of the average noble–gas ionization potential. Ti is selected as the sputtering target since the microstructure, phase composition, properties, and stress-state of Ti-based ceramic thin films grown by HIPIMS are known to be strongly dependent on the charge state of Tin+ (n = 1, 2, …) ions incident at the film growth surface. We find that the flux of Tin+ with n > 2 is insignificant; thus, we measure the Ti2+/Ti+ integrated flux ratio JTi2+/JTi+ at the substrate position as a function of the choice of noble gas–Ne, Ar, Kr, Xe, as well as Ne/Ar, Kr/Ar, and Xe/Ar mixtures -- supporting the plasma. We demonstrate that by changing noble–gas mixtures, JTi2+ varies by more than two orders of magnitude with only a small change in JTi+. This allows the ratio JTi2+/JTi+ to be continuously tuned from less than 0.01 with Xe, which has a low first-ionization potential IP1, to 0.62 with Ne which has a high IP1. The value for Xe, IPXe1=12.16eV, is larger than the first ionization potential of Ti, IPTi1=6.85eV, but less than the second Ti ionization potential, IPTi2=13.62eV. For Ne, however, IPNe1=21.63eV is greater than both IPTi1 and IPTi2. Therefore, the high-energy tail of the plasma-electron energy distribution can be systematically adjusted, allowing JTi2+/JTi+ to be controllably varied over a very wide range.

Interaction of Al with O2 exposed Mo2BC

A Mo2BC(040) surface was exposed to O2. The gas interaction was investigated using ab initio molecular dynamics and X-ray photoelectron spectroscopy (XPS) of air exposed surfaces. The calculations suggest that the most dominating physical mechanism is dissociative O2 adsorption whereby MoO, OMoO and Mo2CO bond formation is observed. To validate these results, Mo2BC thin films were synthesized utilizing high power pulsed magnetron sputtering and air exposed surfaces were probed by XPS. MoO2 and MoO3 bond formation is observed and is consistent with here obtained ab initio data. Additionally, the interfacial interactions of O2 exposed Mo2BC(040) surface with an Al nonamer is studied with ab initio molecular dynamics to describe on the atomic scale the interaction between this surface and Al to mimic the interface present during cold forming processes of Al based alloys. The Al nonamer was disrupted and Al forms chemical bonds with oxygen contained in the O2 exposed Mo2BC(040) surface. Based on the comparison of here calculated adsorption energy with literature data, AlAl bonds are shown to be significantly weaker than the AlO bonds formed across the interface. Hence, AlAl bond rupture is expected for a mechanically loaded interface. Therefore the adhesion of a residual Al on the native oxide layer is predicted. This is consistent with experimental observations. The data presented here may also be relevant for other oxygen containing surfaces in a contact with Al or Al based alloys for example during forming operations.

Optical properties of diamond like carbon films containing copper, grown by high power pulsed magnetron sputtering and direct current magnetron sputtering: Structure and composition effects

In the present study chemical composition, structure and optical properties of hydrogenated diamond like carbon films containing copper (DLC:Cu films) deposited by reactive magnetron sputtering were studied. Different modes of deposition — direct current (DC) sputtering and high power pulsed magnetron sputtering (HIPIMS) as well as two configurations of the magnetron magnetic field (balanced and unbalanced) were applied. X-ray diffractometry, Raman scattering spectroscopy, energy-dispersive X-ray spectroscopy and atomic force microscopy were used to study the structure and composition of the films. It was shown that by using HIPIMS mode contamination of the cathode during the deposition of DLC:Cu films can be suppressed. In all cases oxygen atomic concentration in the films was in 5–10at.% range and it increased with the copper atomic concentration. The highest oxygen content was observed in the films deposited employing low ion/neutral ratio balanced DC magnetron sputtering process. According to the analysis of the parameters of Raman scattering spectra, sp3/sp2 bond ratio decreased with the increase of Cu atomic concentration in the DLC films. Clear dependence of the extinction, absorbance and reflectance spectra on copper atomic concentration in the films was observed independently of the method of deposition. Surface plasmon resonance effect was observed only when Cu atomic concentration in DLC:Cu film was at least 15at.%. The maximum of the surface plasmon resonance peak of the absorbance spectra of DLC:Cu films was in 600–700nm range and redshifted with the increase of Cu amount. The ratio between the intensities of the plasmonic peak and hydrogenated amorphous carbon related peak at ~220nm both in the extinction and absorbance spectra as well as peak to background ratio of DLC:Cu films increased linearly with Cu amount in the investigated 0–40at.% range. Reflectance of the plasmonic DLC:Cu films was in 30–50% range that could be important in practical optical applications of DLC:Cu films.

The Influence of Pulse Width on Microstructure and Mechanical Properties of CrNx Coatings Deposited by HPPMS

CrNx coatings were deposited by high power pulse magnetron sputtering in a closed field unbalanced system. The influence of pulse width on microstructure and mechanical properties of CrNx coatings was examined. Morphologies different from those fabricated by traditional magnetron sputtering were obtained, phase structures were also changed in the process. The coatings hardness were always improved in the increasing pulse length, while the best adhension of CrNx coatings about 25N was get when pulse length was 60us.