Ar/O2 gas pressure dependences of a pulsed zirconium arc and extracted ion characteristics

A pulsed dc zirconium arc discharge is generated in an argon diluted oxygen gas by separating a pin electrode as an anode from the cathode. The arc is transiently generated, and its life time is approximately 3 ms for a series resistance of 1 Ω and a dc output of 33 V. The life is prolonged and the plasma becomes stable with increasing the arc current. A target with a diameter of 100 mm is set at 150 mm from the arc source, and is immersed in the plasma. A pulse voltage is applied to the target to extract ions from the plasma. The ion current is not detected after approximately 8 ms since the plasma initiation. When the plasma is generated in oxygen without argon, the plasma generation time is scattered, and the plasma is unstable. An ion density is estimated from the temporal behavior of the target voltage in the recovery region after the pulse voltage. The ion density at the target is approximately 2.5 × 10¹⁵ m^− 3 at a mixed gas pressure of 1.9 Pa, which corresponds to the plasma density of 1.1 × 10¹⁷ m^− 3 under an assumption of electron temperature of 1 eV.     

Corrosion resistance of Al ion implanted AZ31 magnesium alloy at elevated temperature

The Al ion implantation into AZ31 magnesium alloy was carried out in a MEVVA 80-10 ion implantation system at an ion energy of 40-50 keV with an ion implantation dose ranging from 2 × 10¹⁶ to 1 × 10¹⁷ ions/cm² at an elevated temperature of 300 °C induced by an ion current density of 26 μA/cm². The concentration-depth profile of implanted Al in AZ31 alloy measured by Rutherford backscattering spectrometry (RBS) is a Gaussian-type-like distribution in a depth up to about 1200 nm with the maximum Al concentration of about 8 at.%. The X-ray diffraction (XRD) analysis revealed the formation of α-Mg(Al) phase, intermetallic β-Mg₁₇Al₁₂, and MgO phase on the Al ion implanted samples. The potentiodynamic anodic polarization curves of the Al ion implanted samples in the 0.01 mol/l NaCl solution with a pH value of 12 showed increases of the corrosion potential and the pitting breakdown potential, and a decrease of the passive current density, respectively. The Al ion implanted samples with 6 × 10¹⁶ ions/cm² achieved the high pitting breakdown potential to about − 480 mV (SCE). In the 0.08 mol/l NaCl solution with pH = 12, the Al ion implanted samples with 1 × 10¹⁷ ions/cm² showed an increased pitting breakdown potential to about − 1290 mV (SCE), from around − 1540 mV (SCE) of unimplanted samples. It is indicated that different corrosion mechanisms are responsible for improvement in corrosion resistance of the AZ31 magnesium alloy in the NaCl solutions with the varied concentrations.     

Investigation of cytocompatibility of surface-treated cellulose nitrate films by using plasma immersion ion implantation

The alpha-particle sensitive colorless cellulose nitrate films (commercially available as LR 115 films from DOSIRAD, France) have been proposed as cell-culture substrates for alpha-particle radiobiological experiments. Cytocompatibility of the substrate is a key factor to the success of such experiments. The present work aims to investigate the cytocompatibility of surface-treated cellulose nitrate films by using plasma immersion ion implantation-deposition. The films were placed in a vacuum chamber, into which nitrogen gas was continuously bled and where the pressure was kept at 2 × 10^− 3 Torr. Implantation was carried out by igniting the nitrogen plasma at 100 W radio-frequency and applying high bias voltage in pulse with 20 μs pulse width and 50 Hz (with 20 kV or no voltage). HeLa cervix cancer cells were then cultured on both the plasma-treated and untreated cellulose nitrate films. Our tests showed that the plasma-treated films are in general more cytologically compatible.     

Influence of oxygen ion irradiation on the corrosion aspects of Ti-5%Ta-2%Nb alloy and oxide coated titanium

The corrosion resistance of Ti-5%Ta-2%Nb alloy and DOCTOR (double oxide coating on titanium for reconditioning) coated titanium by O⁵⁺ ion irradiation were compared and investigated for their corrosion behaviour. O⁵⁺ ion irradiations were carried out at a dose rate of 1 × 10¹⁷, 1 × 10¹⁸ and 1 × 10¹⁹ ions/m² at 116 MeV. The surface properties and corrosion resistance were evaluated by using scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray (EDX), glancing-angle X-ray diffraction (GXRD) and electrochemical testing methods. The results of electrochemical investigations in 11.5 N HNO₃ indicated that the open circuit potential (OCP) of DOCTOR coated titanium is nobler than Ti-5%Ta-2%Nb alloy. The potentiodynamic polarization study of Ti-5%Ta-2%Nb alloy and DOCTOR coated specimen indicated decrease in passive current density with increase in ion doses (1 × 10¹⁷ to 1 × 10¹⁹ ions/m²) indicating decrease in anodic dissolution. Nyquist arc behaviour in the electrochemical impedance study substantiated the enhancement in oxide layer stability by O⁵⁺ ion irradiation. AFM results revealed that the DOCTOR coated Ti surface was dense without gross voids, and the surface roughness decreased by O⁵⁺ ion irradiation, but increased after corrosion test. EDX and GXRD patterns of DOCTOR coated Ti sample indicated that the coating was mainly composed of rutile TiO₂. Based on the above results, the O⁵⁺ ion irradiation effect on corrosion behavior of Ti-5%Ta-2%Nb alloy and DOCTOR coated titanium are discussed in this paper.     

Composition and structure of Al ions implanted Fe at elevated temperatures

Al ions with ion energy of 120 keV are implanted into Fe under ion current density of 3.18 μA/cm² to implantation doses of 5 × 10¹⁶ and 1 × 10¹⁷ ions/cm² at room temperature and elevated temperatures of 250 and 500 °C, respectively. At 250 °C, the distribution depth of implanted Al reaches 160 nm with a peak concentration of 6 at.% at the dose of 5 × 10¹⁶ ions/cm², and 180 nm with 10 at.% at 1 × 10¹⁷ ions/cm², analyzed by Rutherford backscattering spectroscopy, respectively. At 500 °C, the implantation depth is 200 nm and the maximum concentration of Al is 10 at.% at the dose of 1 × 10¹⁷ ions/cm². With 5 × 10¹⁶ ions/cm², the intermetallics Al₁₃Fe₄ is formed in the Fe samples at 500 °C, revealed by X-ray diffraction. With 1 × 10¹⁷ ions/cm², the phase is also detected at 250 °C. The concentration-depth profiles of implanted Al in Fe samples at the room temperature, 250 °C and 500 °C are calculated by a mass transfer model that is built based on the transport of ions in matter and the irradiation enhanced diffusion. The calculated concentration-depth profiles are in reasonable agreement with those obtained from the experiments.     

Effect of swift heavy ion irradiation on bismuth doped BaS nanostructures

We report the use of swift heavy ion irradiation as a means to tailor the luminescence properties of bismuth doped barium sulphide nanostructures. The samples were irradiated with 120 MeV Ni⁺⁹ ions at three different fluences of 1 × 10¹², 5 × 10¹², and 1 × 10¹³ ion/cm². Structural and optical properties of pristine and irradiated samples were carried out using X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL) and UV-vis spectroscopy. X-ray diffraction (XRD) studies were used to estimate the average size of nanoparticles. The average size of the crystallites is estimated from the line widths of the diffraction pattern, while the exact size of the crystallites is estimated from the TEM micrographs. After irradiation with a fluence of 1 × 10¹³ ion/m² the photoluminescence intensity increases by 42%. The indirect band gap of BaS:Bi is increased after ion irradiation.     

Pulsed laser deposition of anatase and rutile TiO2 thin films

The investigation deals with the preparation of both anatase and rutile thin films from a sintered rutile target of TiO₂ by pulsed laser ablation technique. Microstructural characterization of the sintered target was carried out using X-ray diffraction and AC impedance spectroscopy. Thin films of titania were deposited on (111) Si substrates at 673 K in the laser energy range 200-600 mJ/pulse at two different conditions: (i) deposition at 3.5 × 10^− 5 mbar of oxygen, and (ii) deposition at an oxygen partial pressure of 0.1 mbar. The influence of laser energy and oxygen addition on the film growth has been studied. X-ray diffraction analysis of the films indicated that the films are single phasic and nano crystalline. Titania films deposited in the energy range 200-600 mJ/pulse at a base pressure of 5 × 10^− 5 mbar are rutile with particle sizes in the range 5-10 nm, whereas the films formed at the oxygen partial pressure 0.1 mbar are anatase with particle sizes in the range 10-24 nm. In addition, at higher energies, a significant amount of particulates of titania are found on the surface of the films. The change in the microstructural features of the films as a function of laser energy and oxygen addition is discussed in relation with the interaction of the ablated species with the background gas.     

Filtered vacuum arc deposition of undoped and doped ZnO thin films: Electrical, optical, and structural properties

Filtered vacuum (cathodic) arc deposition (FVAD, FCVD) of metallic and ceramic thin films at low substrate temperature (50-400 °C) is realized by magnetically directing vacuum arc produced, highly ionized, and energetic plasma beam onto substrates, obtaining high quality coatings at high deposition rates. The plasma beam is magnetically filtered to remove macroparticles that are also produced by the arc. The deposited films are usually characterized by their good optical quality and high adhesion to the substrate. Transparent and electrically conducting (TCO) thin films of ZnO, SnO₂, In₂O₃:Sn (ITO), ZnO:Al (AZO), ZnO:Ga, ZnO:Sb, ZnO:Mg and several types of zinc-stannate oxides (ZnSnO₃, Zn₂SnO₄), which could be used in solar cells, optoelectronic devices, and as gas sensors, have been successfully deposited by FVAD using pure or alloyed zinc cathodes. The oxides are obtained by operating the system with oxygen background at low pressure. Post-deposition treatment has also been applied to improve the properties of TCO films.The deposition rate of FVAD ZnO and ZnO:M thin films, where M is a doping or alloying metal, is in the range of 0.2-15 nm/s. The films are generally nonstoichiometric, polycrystalline n-type semiconductors. In most cases, ZnO films have a wurtzite structure. FVAD of p-type ZnO has also been achieved by Sb doping. The electrical conductivity of as-deposited n-type thin ZnO film is in the range 0.2-6 × 10^− 5 Ω m, carrier electron density is 10²³-2 × 10²⁶ m^− 3, and electron mobility is in the range 10-40 cm²/V s, depending on the deposition parameters: arc current, oxygen pressure, substrate bias, and substrate temperature. As the energy band gap of FVAD ZnO films is ∼ 3.3 eV and its extinction coefficient (k) in the visible and near-IR range is smaller than 0.02, the optical transmission of 500 nm thick ZnO film is ∼ 0.90.     

Corrosion behaviour of nitrogen ion implanted AISI type 304L stainless steel in nitric acid medium

The effects of nitrogen ion implantation on corrosion behaviour of 304L stainless steel in 1 N HNO₃ medium were investigated using surface analytical and electrochemical techniques. Nitrogen ion was implanted at 70 keV in the dose range of 1 × 10¹⁵, 1 × 10¹⁶, 1 × 10¹⁷ and 2.5 × 10¹⁷ N⁺/cm², respectively. Grazing incidence X-ray diffraction results for unimplanted and up to dose of 1 × 10¹⁶ N⁺/cm² showed co-existence of γ-Fe and α′-Fe and, at higher doses (1 × 10¹⁷ and 2.5 × 10¹⁷) preferential formation of chromium nitride was observed. X-ray photoelectron spectroscopy investigation confirmed the formation of chromium nitride at higher doses. Electrochemical corrosion investigation revealed nobler open circuit potential, decrease in corrosion current densities, passive current densities and increase in polarization resistance with increase in dose rate. Surface morphology analysis after polarization study using atomic force microscope showed grain boundary dissolution for unimplanted specimens and resistance to surface dissolution with increase in dose rate for implanted specimens.     

Surface characterization of ultra high molecular weight polyethylene modified by swift heavy ion beam bombardment

The damage processes induced by swift heavy ions (SHI), can be very different to those induced by classical low ionising particles. This is due to the high electronic stopping power of SHI. Ultra high molecular weight polyethylene (UHMWPE) was irradiated with 6.77 MeV helium and 12.5 MeV carbon beams and fluences ranging from 10¹¹ to 10¹³ cm^− 2 and 2 × 10¹⁰ to 5 × 10¹³ cm^− 2, respectively. Structural changes at the polymer near surface region were studied by means of infrared spectroscopy measurements and wear resistance tests. With FTIR spectroscopy we studied the changes in crystallinity, double bond CC, trans-vynilene and graphite formation and the evolution of methylene group as a function of fluence. The experiments have determined that exists an optimum ion fluence value, that depends on the ion mass and energy, at which the wear resistance increases of about 85% respect to the unirradiated polymer. For helium this value is 2 × 10¹² cm^− 2 and for carbon 4 × 10¹¹ cm^− 2. At these fluence values no sign of graphite was found by FTIR studies. Using a Monte Carlo simulation program we determined that the surface area affected by the track core of the incoming ions was less than 19 and 35% for helium and carbon respectively.     

Nitrogen-PBII modification of ultra-high molecular weight polyethylene: Composition, structure and nanomechanical properties

Plasma based ion implantation of nitrogen was performed on mechanically polished UHMWPE model samples by applying 27.13 MHz RF energized low pressure N₂ plasma with 15-30 kV pulses and fluences up to 5 · 10¹⁷ ions/cm². Surface compositional and structural alterations and nanomechanical property changes were investigated by XPS, Raman and by nano-indentation and nano-scratch techniques. The implanted N amounted up to 13-20 at.% (N/C = 0.18-0.30), while a significant amount of oxygen could also be detected on the surface. Three types of chemical states of the incorporated nitrogen were detected, related to linear sp² CN-C and to planar and non-planar sp³ type C-N bonds. The applied PBII treatment led to severe dehydrogenation of the polyethylene resulting in conversion of the surface into a nitrogen-containing DLC type structure. Up to four-fold increase of the hardness at 50-100 nm depth was measured compared to the untreated samples. The scratch volume, characterising the wear resistance, decreased also significantly down to 25-35% of the original value.     

Effect of electrolyte additives on anti-corrosion ability of micro-arc oxide coatings formed on magnesium alloy AZ91D

Oxide coatings on AZ91D alloy were prepared using micro-arc oxidation techniques at a low applied voltage, in electrolyte solutions with hexamethylenetetramine and sodium borate additives. The different electrolyte solutions changed the applied voltage from 400 to 200 V and reduced the micro-pore size of the oxide coating on the AZ91D alloy.The corrosion current of the oxide coating changed from 3.6 × 10^− 5 to 4.2 × 10^− 7 A/cm² when the additives were added to the plating solution. When sodium borate was added to the plating solution, the Na content of the oxide coating was increased, improving its anti-corrosion ability. Moreover, the surface roughness (Ra) was reduced from 10.12 to 1.22 by the addition of 0.1 M hexamethylenetetramine to the electrolyte. The cracks in the oxide coating were also smoothed by the addition of 0.1 M hexamethylenetetramine, reducing the thermal stress.In this work, the addition of the aforementioned additives to the alkaline silicate phosphate electrolyte reduced the applied voltage and modified the oxide coating, resulting in better anti-corrosion ability.     

On time-of-flight ion energy deposition into a metal target by high-intensity pulsed ion beam generated in bipolar-pulse mode

The energy deposition of high-intensity pulsed ion beam (HIPIB) into a titanium target was studied in TEMP-6 apparatus of bipolar-pulse mode using a self-magnetic field magnetically insulated ion diode (MID), where anode plasma was pre-generated by a first negative voltage and then mixed carbon ions and proton beam was extracted during the positive stage of the bipolar pulse. According with the time-of-flight (TOF) of ions, C⁺ arriving at the target 14 cm downstream from the MID was delayed by 55 ns relative to H⁺ at a peak accelerating voltage of 250 kV and the ion energy spectrum varied greatly, starting with a Gaussian profile at exit of MID and arriving with a multi-energy complex distribution. The TOF ion energy deposition of HIPIB showed that the energy deposition proceeded firstly in a deeper depth delivered by H⁺ and then moved towards a top layer dominated by C⁺. It is found that, the contribution of H⁺ to the energy deposition is negligible at the beam composition of 70%C⁺ and 30%H⁺. As a result, the gradient of energy deposition profile in target is negative by C⁺ deposition through the whole pulse. This unique feature of HIPIB energy deposition can lead to different thermal and dynamic effects as compared to previous studies of H⁺-abundant HIPIB, electron or laser beam, especially limiting subsurface heating that is concerned as a major cause of droplet ejection and surface cratering and waviness formation.     

Growth of ZnO nanorods by air annealing of ZnO films with an applied electric field

A novel method of ZnO nanorods growth is presented based on low temperature (300 °C) air annealing of ZnO film while applying an electric field (∼ 10 V/cm) parallel to the film. The films were deposited on glass substrates using a filtered vacuum arc deposition system equipped with a Zn cathode, at an arc current of 160 A, oxygen pressure of 3.2 mTorr, and deposition time of 30 s. Cu tape electrodes were applied on each end of the coated sample, and used to apply the electric field. The samples were annealed in a quartz furnace at 200, 300, 400 °C for 20 or 60 min. Each sample surface was examined using a Scanning Electron Microscope (SEM) and a High Resolution SEM (HRSEM) to study its micro- and nano-structure. The film crystallographic structure was studied using X-ray diffractometry (XRD). ZnO rods with lengths of ∼ 3 μm were observed on the samples annealed at 300 °C for 20 min with an electric field of ∼ 10³ V/m, while separated conical forms with lengths of ∼ 0.5 μm and base width of ∼ 150 nm were observed after annealing under the same conditions but without any electric field. The rod growth rate and area density were ∼ 2.0-2.5 nm/s, and ∼ 3 × 10⁷ cm^− 2, respectively.     

High-energy heavy ion beam annealing effect on ion beam synthesis of silicon carbide

Silicon carbide (SiC) is a superior material potentially replacing conventional silicon for high-power and high-frequency microelectronic applications. Ion beam synthesis (IBS) is a novel technique to produce large-area, high-quality and ready-to-use SiC crystals. The technique uses high-fluence carbon ion implantation in silicon wafers at elevated temperatures, followed by high-energy heavy ion beam annealing. This work focuses on studying effects from the ion beam annealing on crystallization of SiC from implanted carbon and matrix silicon. In the ion beam annealing experiments, heavy ion beams of iodine and xenon, the neighbors in the periodic table, with different energies to different fluences, I ions at 10, 20, and 30 MeV with 1-5 × 10¹² ions/cm², while Xe ions at 4 MeV with 5 × 10¹³ and 1 × 10¹⁴ ions/cm², bombarded C-ion in implanted Si at elevated temperatures. X-ray diffraction, Raman scattering, infrared spectroscopy were used to characterize the formation of SiC. Non-Rutherford backscattering and Rutherford backscattering spectrometry were used to analyze changes in the carbon depth profiles. The results from this study were compared with those previously reported in similar studies. The comparison showed that ion beam annealing could indeed induce crystallization of SiC, mainly depending on the single ion energy but not on the deposited areal density of the ion beam energy (the product of the ion energy and the fluence). The results demonstrate from an aspect that the electronic stopping plays the key role in the annealing.     

A study of suppression effect of oxygen contamination by bias voltage in reactively sputtered ZrN films

A scrupulous cleaning and degreasing of the deposition chamber allows to make a ZrN film with stoichiometry of 1.3 and to achieve a level of oxygen contamination equal to 5%. This film exhibits a low number of carriers estimated at N* = 3 × 10²¹ cm^− 3 and with a very high electrical resistivity value of about 10⁵ μΩ·m. This result points the way for further improvements in the quality of the material.This amount of oxygen contamination may be reduced in conditions in which only the oxygen will be removed without disturbing the zirconium presence in the film. A bias voltage value between 8 eV and 20 eV reduces the oxygen contamination.The ionic assistance is often proposed as a mean to minimize the oxygen contamination. However, one must consider the negative phenomena as re-sputtering, ion implantation, atom displacement and stress generation that introduce defects in the film and affect its properties. This work proposes a very low bias voltage value to control oxygen contamination. The bias voltage value is chosen higher than the nitrogen sputtering threshold energy and lower than the argon sputtering threshold energy. The re-sputtering phenomenon, far from being a problem, can be used to achieve the stoichiometry if one starts from a nitrogen-rich compound. In this way, ZrN_x is grown with x about 1, with an effective free electron concentration N* = 8.9 × 10²¹ cm^− 3. Furthermore its resistivity value is about 2 μΩ·m and the oxygen Secondary Ion Mass Spectrometry (SIMS) signal is similar to the noise signal.     

Parametric study of nitrided AISI 304 austenite stainless steel prepared by plasma immersion ion implantation

This paper investigates the characteristics of plasma immersion nitrogen-ion implanted AISI 304 austenite stainless steel against such processing parameters as bias voltage (5-20 kV), substrate temperature (300-500 °C), and implantation fluence (1.4 × 10¹⁸-4.2 × 10¹⁸ cm^− 2). Characteristics of the as-implanted specimens under investigation included elemental depth profile, hardness depth profile, crystallographic structure, and corrosion behavior and were determined using glow discharge spectrometry (GDS), the Vickers hardness tester, X-ray diffractometry (XRD), and the potentiodynamic polarization test, respectively. The results show that nitrogen depth profiles strongly depend on these processing parameters and closely relate to the corresponding chromium depth profiles. The hardness depth profiles increase and widen as substrate temperature, bias voltage, and implantation fluence increase. In particular, an improvement in hardness is accompanied by a reduction in corrosion resistance when substrate temperature reaches 500 °C. The corrosion-resistance degrader, CrN, precipitates as substrate temperature exceeds 450 °C, a phenomenon which is clearly evident in the chromium depth profiles as well as the XRD results.     

High-repetition rate pulsed laser deposition of ZrC thin films

ZrC thin films were grown on (100) Si substrates by the pulsed laser deposition (PLD) technique using a high-repetition rate excimer laser working at 40 Hz. The substrate temperature during depositions was set at 300 °C and the cooling rate was 5 °C/min. X-ray diffraction investigations showed that the films were crystalline. Films deposited under residual vacuum or 2 × 10^− 3 Pa of CH₄ atmosphere exhibited a (200)-axis texture, while those deposited under 2 × 10^− 2 Pa of CH₄ atmosphere were found to be equiaxed. The surface elemental composition of as-deposited films, analyzed by Auger electron spectroscopy (AES), showed the usual high oxygen contamination of carbides. Once the topmost − 3-5 nm region was removed, the oxygen concentration rapidly decreased, being around 3-4% only in bulk. Scanning electron microscopy (SEM) investigations showed a smooth, featureless surface morphology, corroborating the roughness values below 1 nm (rms) obtained from simulations of the X-ray reflectivity (XRR) curves. From the same simulations we also estimated films mass density values of around 6.32-6.57 g/cm³ and thicknesses that correspond to a deposition rate of around 8.25 nm/min. Nanoindentation results showed a hardness of 27.6 GPa and a reduced modulus of 228 GPa for the best quality ZrC films deposited under an atmosphere of 2 × 10^− 3 Pa CH₄.     

Low temperature growth of nanocrystalline TiO2 films with Ar/O2 low-field helicon plasma

TiO₂ thin films were deposited on silicon wafer substrates by low-field (1 < B < 5 mT) helicon plasma assisted reactive sputtering in a mixture of pure argon and oxygen. The influence of the positive ion density on the substrate and the post-annealing treatment on the films density, refractive index, chemical composition and crystalline structure was analysed by reflectometry, Rutherford backscattering spectroscopy (RBS) and X-ray diffraction (XRD). Amorphous TiO₂ was obtained for ion density on the substrate below 7 × 10¹⁶ m^− 3. Increasing the ion density over 7 × 10¹⁶ m^− 3 led to the formation of nanocrystalline (~ 15 nm) rutile phase TiO₂. The post-annealing treatment of the films in air at 300 °C induced the complete crystallisation of the amorphous films to nanocrystals of anatase (~ 40 nm) while the rutile films shows no significant change meaning that they were already fully crystallised by the plasma process. All these results show an efficient process by low-field helicon plasma sputtering process to fabricate stoichiometric TiO₂ thin films with amorphous or nanocrystalline rutile structure directly from low temperature plasma processing conditions and nanocrystalline anatase structure with a moderate annealing treatment.     

High rate deposition of thick CrN and Cr2N coatings using modulated pulse power (MPP) magnetron sputtering

As a variation of high power pulsed magnetron sputtering technique, modulated pulse power (MPP) magnetron sputtering can achieve a high deposition rate while at the same time achieving a high degree of ionization of the sputtered material with low ion energies. These advantages of the MPP technique can be utilized to obtain dense coatings with a small incorporation of the residual stress and defect density for the thick coating growth. In this study, the MPP technique has been utilized to reactively deposit thick Cr₂N and CrN coatings (up to 55 μm) on AISI 440C steel and cemented carbide substrates in a closed field unbalanced magnetron sputtering system. High deposition rates of 15 and 10 μm per hour have been measured for the Cr₂N and CrN coating depositions, respectively, using a 3 kW average target power (16.7 W/cm² average target power density), a 50 mm substrate to target distance and an Ar/N₂ gas flow ratio of 3:1 and 1:1. The CrN coatings showed a denser microstructure than the Cr₂N coatings, whereas the Cr₂N coatings exhibited a smaller grain size and surface roughness than those of the CrN coatings for the same coating thickness. The compressive residual stresses in the CrN and Cr₂N coatings increased as the coating thickness increased to 30 μm and 20 μm, respectively, but for thicker coatings, the stress gradually decreased as the coating thickness increased. The CrN coatings exhibited an increase in the scratch test critical load as the thickness was increased. Both CrN and Cr₂N coatings showed a decrease in the hardness and an increase in the sliding coefficient of friction as the coating thickness increased from 2.5 to 55 μm. However, the wear rate of the CrN coatings decreased significantly as the coating thickness was increased to 10 μm or higher. The 10-55 μm CrN coating exhibited low wear rates in the range of 3.5-5 × 10⁻⁷ mm³ N⁻¹ m⁻¹. To the contrary, the Cr₂N coating exhibited relatively low wear resistance in that high wear rates in the range of 3.5 to 7.5 × 10⁻⁶ mm³ N⁻¹ m⁻¹ were observed for different thicknesses.