Hollow Cathode Discharge Ion Plating Research Articles

Hydrogen permeation resistance of ZrN thin film deposited by ion-plating

Hydrogen absorption of Zircaloy nuclear fuel cladding, used in light water reactor at nuclear power plants, poses an increased risk of delayed hydride cracking during interim dry storage. Consequently, novel surface technologies aimed at reducing hydrogen absorption have become a critical area of research. Zirconium nitride coatings, renowned for their high hardness, corrosion resistance, and wear resistance, have seen widespread application in various industries, including medical devices, cutting tools, and decoration. This study explores the effectiveness of ZrN coating in suppressing hydride formation in Zircaloy-4, a material commonly used for nuclear fuel cladding. In this research, ZrN coatings were deposited onto recrystallized Zircaloy-4 substrates using a hollow cathode discharge ion-plating (HCD-IP) system. The coated and uncoated Zircaloy-4 samples were then subjected to electrochemical and gaseous hydriding processes. The study further investigates the differences in microstructure and hydrogen content of coated and uncoated Zircaloy-4. From these results, it is evident that the ZrN thin film deposited by HCD-IP exhibited great resistance to hydrogen permeation against both hydriding conditions. It is concluded that the ZrN thin films can serve as an excellent hydrogen barrier layer for Zircaloy-4.

The role of Cu content on the structural properties and hardness of TiN –Cu nanocomposite film

TiN-Cu Nanocomposite coatings with different Cu contents were prepared by co-deposition in a hollow cathode discharge ion plating system. The influence of Cu content in the range of 2–7 at.% on the microstructure, morphology and mechanical properties of the deposited films were investigated. Structural properties of the films were studied by X-ray diffraction pattern (XRD). The composition and morphology of the coatings were characterized using energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM), respectively. Atomic force microscopy (AFM) and nanoindentation were used to study topography and mechanical properties of deposited films, respectively. In addition, X-ray photoelectron spectroscopy (XPS) analysis was performed to study the surface chemical bonding states. It was found that Cu and TiN phases grew separately and formation of Cu-N bond or Ti-Cu-N ternary phase was not detected in this study. Moreover, it was shown that addition of the soft Cu phase to TiN film above 2 at.% drastically decreased the film hardness from 30 to 2.8 GPa due to lubricant effect of segregated Cu particles.

The effect of bias voltage on microstructure and hardness of TiN films grown by ion coating deposition

Titanium nitride (TiN) thin films were grown onto 316 stainless steel substrate at 350 ° C by hollow cathode discharge ion plating technique. Since microstructure and mechanical properties of the samples were strongly affected by bias voltage, different bias voltages from 0 to | − 120| V were applied to the substrate. Rutherford back-scattering spectroscopy showed that the film thickness decreased when the bias voltage increased. X-ray diffraction patterns showed that the as-prepared TiN thin films were preferentially grown in the (200) direction with a satisfactory crystal quality at −30 V. The spatial scaling behavior of the TiN films grown by ion coating have been investigated by using the atomic force microscopy as well as a kinetic roughening model for the film thickness ranging from 380 to 590nm. The roughness and dynamic scaling exponents have been independently measured (α = 0.7 ± 0.05 and Z = 3.03 ± 0.05) and they exhibited a smooth surface growth. Nanohardness showed formation of a film with 30GPa hardness and 285 GPa Young modulus at −30 V bias voltage.

Effect of Cu Content on TiN-Cu Nanocomposite Film Properties: Structural and Hardness Studies

Titanium nitride-Copper (TiN-Cu) nanocomposite films were deposited onto stainless steel substrate using hollow cathode discharge ion plating technique. The influence of Cu content in the range of 2-7 at.% on the microstructure, morphology and mechanical properties of deposited films were investigated. Structural properties of the films were studied by X-ray diffraction pattern. Topography of the deposited films was studied using atomic force microscopy. Film hardness was estimated by a triboscope nanoindentation system. However, X-ray photoelectron spectroscopy analysis was performed to study the surface chemical bonding states. It was found that addition of soft Cu phase above 2 at.% to TiN film drastically decreased the film hardness from 30 to 2.8 Gpa due to lubricant effect of segregated copper particles. X-ray photoelectron spectroscopy results showed that Cu and TiN phases grew separately. In our case,the formation of a solid solution or chemical bonding between Cu and Ti was rejected.

Comparison of the mechanical performance of cutting tools coated by either a TiC xN 1 − x single-layer or a TiC/TiC 0.5N 0.5/TiN multilayer using the hollow cathode discharge ion plating method

TiC xN 1 − x single-layer (x = 0–1.0) and TiC/TiC 0.5N 0.5/TiN multilayer coatings prepared using the hollow cathode discharge (HCD) ion plating method were investigated to improve the mechanical performance of high speed steel cutting tools. The carbon/nitrogen ratio of the TiC xN 1 − x coating was controlled by adjusting the composition of an additional acetylene/nitrogen mixture gas during the ion plating process. The mechanical performance characteristics of the coated cutting tools, such as the surface hardness, adhesion, wear and dynamic hardness, were studied. The cutting tools coated by the multilayer films showed higher wear resistance and longer use life than those coated by TiC xN 1 − x single-layer films. The higher dynamic hardness of the multilayer coatings was considered the primary contributor to the improvement of the mechanical properties.

Structure and properties of nanocrystalline ZrNxOy thin films: Effect of the oxygen content and film thickness

The main objective of this study was to investigate the structure and properties of ZrNxOy thin films associated with oxygen content and film thickness. ZrNxOy thin films were deposited using hollow cathode discharge ion plating on Si (100) substrate. The thickness of ZrNxOy films increased with increasing oxygen flow rate, ranging from 143 to 894 nm. Phase separation from ZrNxOy to ZrN and monoclinic ZrO2 (m-ZrO2) was observed by x-ray diffraction (XRD). The electrical and mechanical properties were influenced by the film thickness and the amount of separated phase, m-ZrO2. ZrNxOy thin films with smaller thickness or deposited at higher O2 flow rate were found to have higher electrical resistivity. Hardness of the ZrNxOy thin films increased with increasing thickness, which could be related to microstructure change of the thin films. Residual stress of the ZrN phase in the ZrNxOy thin films, measured using the modified sin2 ψ XRD method, decreased with increasing oxygen flow rate. The thickness dependence of the residual stress in ZrN was different with different oxygen flow rates. The average residual stress of the ZrNxOy thin films also decreased with increasing oxygen flow rate and the stress did not showed significant dependence on the film thickness.

Tribological performance evaluation of (1 1 1) preferred oriented TiN duplex coatings

The duplex surface coating of hot work tool steel, which comprises nitriding of a substrate and coating of a TiN layer, has been the subject of a series of studies as a potential surface modification for tools and machine parts. Through sliding experiment against an aluminum alloy without lubrication, it was shown on a wear map that there are two domains depending on sliding conditions: the wear domain and the transfer domain. In this study, focusing on the improvement in the tribological properties of the duplex coating in terms of the wear domain, the effects of film characteristics on film resistance to erosion wear and film life were investigated. Two kinds of duplex coatings with different film characteristics were prepared by hollow cathode discharge ion plating: a newly developed TiN film with a strong (1 1 1) orientation and an ordinary TiN film with (1 1 1) and (2 0 0) orientations. The erosion wear rate of duplex coating was evaluated by a micro slurry jet erosion test. Film life was evaluated by a sliding test against an aluminum alloy as in previous experiments. It was revealed that the duplex coating with the newly developed TiN film (N-coating) shows higher erosion resistance than previously reported duplex coating (C-coating). From the sliding test, it was also revealed that the N-coating whose XRD intensity ratio of (1 1 1) to (2 0 0) is over 100 shows a wear mode with only chipping, with no scratching, which shortens film life. The film life of N-coating increases about twice as long as C-coating, which has shown higher performance than a conventional duplex coating. Possible mechanisms of the improvement in the tribological properties with N-coating are discussed.

Microstructure study of a nanocrystalline two-phase ZrN xO y thin film

A nanocrystalline ZrN x O y thin film was deposited using hollow cathode discharge ion-plating (HCD-IP). ZrO 2 and ZrN phases were detected by X-ray diffraction in the as-deposited film, suggesting phase separation during the growth process. This research performed a transmission electron microscopy (TEM) study on the mechanism of phase-separation and distribution in ZrN x O y thin films and related the phase fraction with the film properties. Since the crystallographic orientations of the ZrO 2 and ZrN phases are random, the microstructure of the separated phases is studied with multiple central dark-field (MCDF) technique. The compositional distribution between the separated phases is analyzed with nano-beam energy dispersive X-ray spectroscopy (EDX). The results showed that zirconium oxynitride (ZrN x O y ) thin film has a columnar structure with an alternate arrangement of columns of ZrN and ZrO 2, indicating that oxygen atoms are inter-columnarly segregated with a lateral diffusion distance lower than 20 nm.

Heat treatment induced phase separation and phase transformation of ZrN xO y thin films deposited by ion plating

Nanocrystalline ZrN x O y thin films were deposited on p-type Si (100) substrates using hollow cathode discharge ion-plating (HCD-IP) and the films were annealed at 700 and 900 °C in the controlled atmosphere. The purpose of this study was to investigate the phase separation, phase transformation and the accompanying change of properties of the heat-treated ZrN x O y films deposited by ion plating. With the increase of oxygen flow rate ranging from 0 to 10 sccm, the primary phase of the as-deposited films evolved from ZrN to nearly amorphous structure and further to monoclinic ZrO 2 (m-ZrO 2). After heat treatment at 700 and 900 °C, phase transformation occurred in the samples deposited at 8 and 10 sccm O 2, where a stoichiometric crystalline Zr 2ON 2 was found to derive from m-ZrO 2 with dissolving nitrogen (m-ZrO 2(N)). The hardness of the ZrN x O y thin films could be correlated to the fraction of Zr 2ON 2 + m-ZrO 2. The film hardness decreased significantly as the fraction of ZrO 2 + Zr 2ON 2 exceeded ~ 60%, which was due to phase transition by increasing oxygen flow rate or phase transformation induced by heat treatment. The phase separation of m-ZrO 2 from ZrN with dissolving oxygen (ZrN(O)) may relieve the residual stress of the ZrN x O y specimens deposited at 5 and 8 sccm O 2, while direct formation of m-ZrO 2 increased the stress of the film deposited at 10 sccm O 2. On the other hand, the phase transformation from m-ZrO 2(N) to Zr 2ON 2 by heat treatment at both 700 and 900 °C may effectively relieve the residual stress of the ZrN x O y films.

TiAlSiN Coatings Prepared by Hybrid PVD Technology for High Speed Milling of Hardened Steel

TiAlSiN coatings with different Al content were prepared by hollow cathode discharge ion plating (HCDIP) and medium frequency magnetron sputtering ion plating (MFMSIP) hybrid physical vapor deposition (PVD) coating system. The composition, microstructure, mechanical properties of these coatings were systematically investigated by means of EDX, XRD, SEM, nanoindentation, scratch and tribological tests. It was found that the coatings had (111) or (200) preferred orientation with addition of Al. Proper content of Al led to increase of microhardness and adhesion. The flank wear of carbide end mill coated with TiAlSiN had the least wear than those coated with TiAlN and TiSiN coatings under the high speed milling of hardened steel experiments.

ホロカソード型イオンプレーティングで作製したCr-N系薄膜(HDCr)の評価

ホロカソード型イオンプレーティングで作製したCr-N系薄膜(HDCr)の評価

Optimization of hybrid PVD process of TiAlN coatings by Taguchi method

Taguchi method was applied to optimize the performances of TiAlN coatings deposited by hollow cathode discharge ion plating (HCDIP) and medium frequency magnetron sputtering ion plating (MFMSIP) hybrid physical vapor deposition (PVD) coating system. TiAlN coatings prepared by this coating system showed columnar microstructure with the preferred orientation of (1 1 1). The sensitive parameters on microhardness were total deposition pressure and substrate bias voltage, and the sensitive parameter on milling performance was substrate bias voltage. The optimum conditions were total deposition pressure: 0.9 Pa, flowrate of N 2: 250 sccm, substrate bias voltage: −120 V. And the confirming experiment obtained the optimum TiAlN coating with microhardness of 25.8 GPa, and the best TiAlN-coated end mill performed the milling length of 50.8 m.

Mechanical properties and corrosion resistance of nanocrystalline ZrN xO y coatings on AISI 304 stainless steel by ion plating

Transition metal oxynitrides have become emerging decorative coating materials due to their adjustable coloration and high hardness and corrosion resistance. This research studied the effect of oxygen content on the coloration, mechanical properties and corrosion resistance of ZrN x O y thin films deposited on AISI 304 stainless steel using hollow cathode discharge ion plating (HCD-IP). The Zr/N/O ratios of the ZrN x O y films were determined using X-ray photoelectron spectroscopy (XPS). The color of the ZrN x O y thin film changed from golden yellow to blue and then slate blue with increasing oxygen content. X-ray diffraction (XRD) patterns revealed that phase separation of ZrN and m-ZrO 2 occurred as the oxygen content reached 31.2 at.%. ZrN(O) (ZrN with dissolving oxygen) is dominant at oxygen content less than 18.1 at.%, while m-ZrO 2 phase was prevailed at oxygen content above 40.3 at.%. Phase separation lowered the hardness of the ZrN x O y films as the fraction of ZrO 2 was less than 40%. The residual stresses in ZrN phase was higher than that in ZrO 2, and the residual stress decreased for the specimen containing 30 to 37% ZrO 2. For the samples containing more than 44% ZrO 2, the average residual stress was close to that in ZrO 2 phase. The corrosion resistance was evaluated by salt spray test and potentiodynamic scan in two solutions: 0.5MH 2SO 4 + 0.05 M KSCN and 5% NaCl solutions. The results showed consistent trend in the two solutions. From the results of potentiodynamic scan, corrosion resistance increased as the packing density of the film increased, whereas the film thickness was not a crucial factor on corrosion current; moreover, the electrical conductivity of the film may be one of the significant factors in corrosion resistance. Results of salt spray tests suggested that the corrosion of ZrN x O y in NaCl may play an important role in corrosion resistance.

Synthesis and characterization of nanocrystalline ZrN xO y thin films on Si by ion plating

Based on the optimum deposition conditions of ZrN thin film from our previous study, by varying oxygen flow rate ranging from 0 to 8 sccm, nanocrystalline ZrN x O y thin films were deposited on p-type (100) Si substrates using hollow cathode discharge ion-plating (HCD-IP) system. The objective of this study was to investigate the effect of oxygen content on the composition, structure and properties of the ZrN x O y thin films. The oxygen content of the thin film, determined using X-ray photoelectron spectroscopy (XPS), increased with increasing oxygen flow rate. As the oxygen content increased, the color of the ZrN x O y thin film changed from golden yellow to blue and then slate blue, and the microstructure observed by scanning electron microscopy (SEM) varied from columnar structure to finer grains and finally flat and featureless structure. Phase separation of ZrN x O y to ZrN and monoclinic ZrO 2 was found from X-ray diffraction (XRD) patterns when the oxygen content was higher than 9.7 at.%. The hardness of the film slightly increased as the oxygen content was less than 9.7% and then decreased to 15.7 GPa, a typical hardness of ZrO 2 phase, as the oxygen content further increased. The total residual stress of the film was measured using an optical method, and the residual stresses of ZrN and ZrO 2 phases were determined separately using modified XRD sin 2ψ method. The total stress was close to the stress in ZrN phase as the ZrO 2 fraction was less than 30%, and was close to that in ZrO 2 phase as the ZrO 2 fraction was over 30%. The electrical resistivity of the film increased significantly with the increase of oxygen content. The film properties showed consistent trend with phase separation. As the fraction of ZrO 2 phase was small, the apparent properties of the films were more close to those in ZrN. When ZrO 2 fraction was over 30%, the films mainly exhibited the properties of ZrO 2.

Effect of nitrogen flow rate on the structure and mechanical properties of ZrN thin films on Si(1 0 0) and stainless steel substrates

Nanocrystalline ZrN films were successfully deposited on Si(1 0 0) and AISI 304 stainless steel substrates using hollow cathode discharge ion-plating (HCD-IP). The effect of nitrogen flow rate (ranging from 5 to 35 sccm) was investigated on the N/Zr ratio, structure, and mechanical properties of the ZrN films. The results showed that the variation of nitrogen flow rate did not significantly affect the film thickness, preferred orientation and hardness. The major effects of the nitrogen flow rate were on the N/Zr ratio, packing factor, and grain size of the ZrN films. The N/Zr ratio increased (0.6–0.9) with increasing nitrogen flow rate. The grain sizes of the ZrN films, measured by both X-ray diffraction (XRD) and scanning electron microscopy (SEM), ranging from 15 to 30 nm, generally increased with increasing nitrogen flow rate. The hardness of the nanocrystalline ZrN films, ranging from 23.3 to 26.6 GPa, was not related to the variation of the residual stress. The deformation mechanism of the nanocrystalline ZrN films may be through grain rotation or grain boundary sliding instead of slip by dislocations. Since the electric conductivity of 304 stainless steel is higher than that of Si, the stainless steel substrate can attract more Zr ions than Si substrate. This led to larger deposition rate, roughness, and residual stress for the ZrN film deposited on stainless steel than on Si substrate.

Performance Degradation of TiN-and TiC-deposited AISI316 bipolar plates for proton exchange membrane fuel cells

TiN and TiC were deposited on AISI316 bipolar plates for proton exchange membrane fuel cells (PEMFCs) and their effects on the corrosion resistance and overall cell performance were investigated. TiN with a Ti interlayer and TiC with a Ti interlayer were deposited on AISI316 bipolar plates by hollow cathode discharge (HCD) ion plating. The electrochemical behavior of the metallic bipolar plates was examined using a potentiodynamic method, an electrochemical impedance spectroscopy (EIS), and a single cell test. These results revealed that the TiN and TiC coatings considerably improved the corrosion resistance of AISI316. However, the TiN-deposited AISI316 bipolar plates showed a better cell performance than the TiC-deposited AISI316 bipolar plates. The differences in the cell performance stemmed from the differences in the ohmic resistance and charge transfer resistance.

Effect of film thickness on the structure and properties of nanocrystalline ZrN thin films produced by ion plating

Nanocrystalline ZrN thin films were successfully deposited on Si (100) and AISI 316 stainless steel (316SS) substrates using a hollow cathode discharge ion plating (HCD-IP) method. The objective of this study was to investigate the effect of film thickness on the composition, structure and mechanical properties of the ZrN films. The results showed that (111) was the dominant preferred orientation. The effect of the film thickness was significant on the N/Zr ratio, roughness, grain size and electrical resistivity. The packing factor was only slightly varied with film thickness; and the thinnest specimen, at a ZrN thickness of 160 nm, reached a quite high packing factor of 0.8. Nanoindentation data indicated that hardness of the films was not related to the film texture or residual stress. Since the grain sizes of ZrN films were less than 20 nm, the dislocation pileup or Hall–Petch hardening was not expected to active. The deformation mechanisms of the nanocrystalline ZrN films may be due to grain rotation or grain boundary sliding, instead of a dislocation slip mechanism. The residual stresses of all ZrN films were compressive, and did not vary with film thickness. The residual stress of the ZrN films deposited on Si is lower than that on AISI 316 stainless steel. This may be due to the differences in electrical conductivities and thermal expansion coefficients between Si and 316 stainless steel.

Oxidation behavior of TiN with a Ti interlayer on stainless steel

AbstractCharacterization of the TiN coatings oxidized in air at temperatures at 600 and 700°C for 30 min was carried out by X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM) and Auger electron spectroscopy (AES). TiN thin films with a Ti interlayer were prepared by hollow cathode discharge ion plating on AISI 304 stainless steel. Both XRD and TEM results show that the TiN coatings and Ti interlayer have columnar structure with (111) and (0002) preferred orientations, respectively. AFM results show the existence of pinholes on the surface of specimens due to electropolishing process of the steel substrate, and the surface roughness (Ra) changes from 3.5 nm for the as-deposited specimen to 11.6 nm after oxidation at 700°. After oxidation, the TiO2 oxide layer formed on the specimen surface was porous and retained the columnar structure as the original TiN coating. The microstructure of the Ti interlayer gradually changed from columnar to polycrystalline structure due to grain growth. The Auger elemental depth profiling indicated that interdiffusion of the Ti interlayer with steel substrate had occurred during the oxidation process.

Optimization of the deposition process of ZrN and TiN thin films on Si(1 0 0) using design of experiment method

Zirconium nitride (ZrN) and titanium nitride (TiN) thin films were deposited on Si(100) substrates using hollow cathode discharge ion-plating (HCD-IP) and unbalanced magnetron (UBM) sputtering methods, respectively. Design of experiment (DOE) has long been recognized as a powerful method to optimize a complex process in industry. The purposes of present study were to verify the feasibility and reliability of the application of DOE method on PVD processes and optimize the processing parameters for the deposition process, in which the sensitive parameters that affected the film properties were also identified. For HCD-IP method, four parameters, including substrate temperature, substrate bias, Ar partial pressure, and N2 partial pressure, were selected; for the UBM method, dc power, N2 flow rate, specimen–target distance, and specimen height were chosen to be the operating parameters. After deposition, the thin film structure was characterized by X-ray diffraction (XRD), and high-resolution scanning electron microscopy (SEM). The hardness of the ZrN and TiN films was determined by nanoindentation. The resistivity of thin films was measured by a four-point probe. The roughness of the film was obtained by atomic force microscopy (AFM). The analysis of mean (ANOM) and analysis of variance (ANOVA) were conducted to assess the sensitive parameters and predict the optimum conditions. Based on the statistical analysis, the most sensitive parameters in the HCD-IP process were the substrate bias and the N2 partial pressure and in the UBM process were the dc power and the specimen height. The optimum deposition conditions in each system were also acquired.

Effect of substrate bias on the structure and properties of ion-plated ZrN on Si and stainless steel substrates

This research studied the effect of bias on the microstructure and properties of zirconium nitride (ZrN) deposited on Si (1 0 0) and AISI stainless steel 304. The ZrN films were deposited using hollow cathode discharge ion plating (HCD-IP) method. The optimum coating conditions were first determined using Taguchi experimental method. Based on the optimum conditions, the single-variable experiments on the effect of bias were conducted. The cross-sectional microstructure revealed that the columnar structure of the ZrN film became denser with increasing bias. The results of X-ray diffraction (XRD) showed that all the coating samples exhibited (1 1 1) preferred orientation both on Si and SS304 substrates. To avoid substrate effect, the hardness of the ZrN films was measured by nanoindentation. The hardness values of ZrN films deposited on Si were ranged from 27 to 30 GPa, and on stainless steel 304 were from 32.5 to 40.8 GPa. The ZrN films deposited on the stainless steel were very smooth with a roughness number ranging from 1.1 to 3.9 nm. The N:Zr ratios were determined using X-ray photoelectron spectrometry (XPS) and the results indicated that the films were close to the stoichiometric composition. The resistivity of ZrN films gradually decreased with increasing bias until −120 V and then abruptly increased. The corrosion resistance of ZrN-coated stainless steel was evaluated by standard salt spray test and potentiodynamic scanning in two kinds of solution environments: 5% NaCl and 1N H 2SO 4 +0.05 M KSCN, respectively. The results showed a consistent trend between salt spray test and potentiodynamic scanning. The corrosion resistance increased with bias at bias ranging from 0 to −90 V, then abrupt decreased at −120 V, and then increased again at −150 V. The properties changes of resistivity and corrosion resistance can be explained by the change of film structure due to bias-induced ion bombardment.