Physical Vapor Deposition Magnetron Sputtering Research Articles

WITHDRAWN: Characterization of Ag2O nanorods/TiO2 nanotubes hybrid coating for potential orthopedic implant applications

In this study, the potential of nanorod/nanotube hybrid arrays for orthopedic coatings was explored. The Ag2O nanorods/TiO2 nanotubes (ANRs/TNTs) hybrid coating was synthesized on Ti6Al7Nb using a multi-step procedure involving primary anodization, annealing, and secondary anodization processes. The process began with primary anodization, fostering the growth of TNTs, succeeded by thermal treatment for crystallization, and deposition of an Ag layer using physical vapor deposition (PVD) magnetron sputtering. Subsequently, secondary anodization was conducted on Ti6Al7Nb, which was initially coated with Ag-deposited TNTs, culminating in the formation of a hybrid coating. In the hybrid coating, the mean inner diameter of the TNTs was measured at 32.2 ± 8.0 nm, while the average inner diameter of the ANRs stood at 59.0 ± 30.6 nm. The hybrid coating exhibited notably higher hardness values (75.8 ± 3.2 HV) compared to both anodic TNTs (HV 45.5 ± 1.0) and crystallized TNTs (HV 54.0 ± 1.6), while its adhesion strength reached 871.5 ± 3.86 MPa, highlighting robust bonding with Ti6Al7Nb. In vitro bioactivity results confirmed bone-like apatite layer formation on ANRs/TNTs hybrid coating after 14 days in simulated body fluid (SBF), indicating enhanced bioactivity. These findings open promising avenues for advanced orthopedic coatings, with potential applications in facilitating osseointegration, drug delivery, and localized treatments in future biomedical applications.

Investigation of the growth kinetics of Streptococcus mutans bacteria on Zr-C coating surfaces deposited on 316L stainless steel substrates

The conducted research aims to describe the kinetics of Streptococcus mutans bacteria growth on the surface of Zr-C coatings with varying carbon content deposited on 316L medical-grade stainless steel substrates.The coatings were deposited using the MS PVD (Magnetron Sputtering Physical Vapour Deposition) technique at a constant temperature of 400C. Varying carbon contents in the coatings were achieved by changing the flow rate of acetylene during the process. The dynamics of bacteria growth cultivated at 37C were examined on the surface of the coatings for incubation times ranging from 0 to 72 hours. Generalised logistic functions were utilised for the mathematical description of the obtained results.The produced coatings exhibited varying carbon content, determining the structural composition ranging from a mixture of metallic Zr and ZrC through stoichiometric zirconium carbide to nanocrystalline grains of ZrC in an amorphous carbon matrix. The obtained results unequivocally demonstrate that in the case of ZrC coatings, the carbon content influences both the bacterial growth rate during the proliferation phase and the final population of bacteria.In the conducted research on bacterial population dynamics, only a single strain of Streptococcus mutans was considered, and the mathematical description was limited to reaching a pseudo-steady state by the population.The proposed model can successfully be adapted to describe the dynamics of other individual strains of bacteria dwelling on metallic surfaces as well as coatings.The proposed model can serve as a tool for studying, among other things, inflexion points of logistic curves, which are considered as the boundary between the dominance of anabolic and catabolic processes in the bacterial population.

Investigation of Cu-doped amorphous carbon film in improving corrosion resistance and interfacial conductivity of proton exchange membrane fuel cell

This study investigated Cu-doped a-C films prepared under a substrate bias gradually reducing from 120 to 60 V and different Cu target currents of 0, 0.15, 0.2, 0.3, 0.5 A, respectively, using closed field unbalanced magnetron sputtering physical vapour deposition technique. While the Cu-doped a-C film at the lowest Cu target current of 0.15 A (A0.15) remained an amorphous microstructure, Cu nanoprecipitates occurred at Cu target currents of 0.2–0.5 A. All the Cu-doped a-C films prepared exhibited good combination of corrosion resistance to a corrosive chemical mixture of 0.5 M H2SO4 + 5 ppm HF (as suggested by the corrosion current densities) and interfacial electric conductivity (as demonstrated by the interfacial contact resistance, ICR). Among all coatings, A0.15 showed the best corrosion resistance and interfacial electric conductivity, which is attributable to the precipitate-free Cu-doped amorphous microstructure. The measured current density of A0.15 was 1.95 × 10−7 A/cm2 at 0.6 V (vs. SCE) during potentiodynamic polarization, which was lower than that of the Cu-free a-C film at 7.34 × 10−7 A/cm2. The ICR value of A0.15 was 4.40 mΩcm2 at an assembly pressure of 1.4 MPa, which is about one third of the Cu-free a-C film. This study demonstrates a new deposition strategy combining Cu-doping and the control of substrate bias to improve the corrosion resistance and interfacial electric conductivity of a-C films for PEMFC.

Investigation on tribological characteristics of Al 7075 coated with aluminium chromium nitride (AlCrN) by magnetron sputtering

Structural components used in aerospace, automotive, and civil applications should have an increased shelf life. Fretting wear occurring in aluminum alloys decreases the reliability of the components. This study presents the investigations of tribological characteristics of Al7075, coated with Aluminium Chromium Nitride (AlCrN) by Physical Vapor Deposition (PVD) magnetron sputtering technique. Although Al7075 possesses a high strength-to-weight ratio, it has inadequate resistance against fretting wear. The experimental findings of the wear test (Pin on Disc) reveals that AlCrN coating on Al7075 increases the wear resistance and exhibits a low coefficient of friction. A thin film coating of AlCrN given on Al7075 enhances its tribological and corrosion properties. The existence of AlCrN coating composition on the substrate is confirmed by the results of Energy Dispersive Spectroscopy (EDX). Crystal structural phase analyzed using X-ray diffraction (XRD) shows Face Centered Cubic (FCC) structure for coated Al7075 samples. The pin-on-disc test results show that the wear rate has reduced for coated samples. A salt spray corrosion test is executed to evaluate the corrosion rate for 24 h. When comparing coated samples to uncoated samples, it is found that the corrosion rate is lower for coated samples. The average hardness value of the coated Al7075 sample is higher than the uncoated ones. The surface roughness of the coated sample is observed to be less than that of uncoated Al7075 samples.

Investigating mechanical properties of B4C films produced by magnetron sputtering PVD

Boron carbide thin films have recently garnered significant interest across various fields owing to their exceptional physical and chemical properties, such as high wear and corrosion resistance, as well as high hardness, being the third hardest material after diamond and cubic boron nitride. Different coating methods, including physical vapor deposition (PVD) and chemical vapor deposition (CVD), are used to produce these films. In this study, boron carbide thin films were deposited on single-crystal silicon substrates and high-speed steel (HSS) using magnetron sputtering at varying bias voltages (0, −100, and −200 V) in an argon atmosphere utilizing a B4C target. The process temperature, target power, and revolution speed were held constant at 150 °C, 1.3 kW, and 2 rpm, respectively. The mechanical, morphological, and microstructure properties of the deposited films were examined using FE-SEM, XRD, FTIR, Raman, XPS, Scratch test and Ferroxyl test. Nanoindentation test was conducted to evaluate the hardness values of the films. The experimental findings suggest that substrate bias significantly affects the mechanical, structural, and morphological properties of B4C coatings.

Characterizing the composition, structure, and mechanical properties of magnetron sputtering physical vapor deposition TiN and TiSiN coatings

Ti(Si)N coatings were deposited on Si wafers via magnetron sputtering physical vapor deposition technique. Scanning electron microscopy and atomic force microscopy were used to study the morphologies, grain size, and thicknesses of the different films. X-ray diffraction confirmed the formation of the titanium nitride cubic phase. X-ray photoelectron spectroscopy (XPS) was used to study the silicon and oxygen levels in the films, and high resolution XPS was used to determine the surface oxide to nitride ratios as well as the silicon–nitrogen environment. The hardness of these films was then determined with nanoindentation. It was shown that grain size and film density could be controlled by the Si level and the ion bombardment to eliminate the oxygen level in the nitride coatings, which led to the harder films. It was suggested that due to the miscibility of Si, a ternary TiSiN solid solution was formed. Stronger (200) orientation of the TiN B1-NaCl crystals was associated with increased hardness of the coatings. This crystalline structure was preserved after incorporating Si.

Different methods of hydroxyapatite‐based coatings on external fixator pin with high adhesion approach

AbstractIn this review paper, different methods of hydroxyapatite‐based coatings on external fixation pins with improvement in the adhesion strength are explained. Different coating methods such as dip coating, surface‐induced mineralization, plasma spraying, physical vapor deposition magnetron sputtering, micro‐arc oxidation, electrophoretic deposition, chemical vapor deposition, ion beam assisted deposition, sol‐gel dip coating, pulsed laser deposition, and electrohydrodynamic coating are investigated. The micro‐arc oxidation method showed high degradation delaying of the substrate with a high‐voltage electrolyte solution. Moreover, controlling the coating porosity by applying the gas is a good feature of the physical vapor deposition magnetron sputtering method. The comparison of the hydroxyapatite (HA) coatings method showed that the plasma spraying method leads to better coating features between the coating methods on the implant pins.

The Influence of H Content on the Properties of a-C(W):H Coatings

Diamond-like-carbon “DLC” coatings can be deposited in many different ways, giving a large range of material properties suitable for many different types of applications. Hydrogen content significantly influences the mechanical properties and the tribological behavior of DLC coatings, but its determination requires techniques that are not available in many research centers. Thus, it is important to find alternative indirect techniques, such as Raman spectroscopy or nanoindentation (hardness measurements), which can give comparative and indicative values of the H contents in the coatings, particularly when depositions with a reactive gas flow are being studied. In this work, “DLC” composite coatings with varying H content were deposited via Physical Vapor Deposition (PVD) magnetron sputtering in a reactive atmosphere (Ar + CH4). An Ion Beam Analysis was used to determine the elemental depth profile across the coating thickness (giving both average C:W:H ratios and film density when combined with profilometer measurements of film thickness). The hardness was evaluated with nanoindentation, and a decrease from 16 to 6 GPa (and a decrease in the film density by a factor of two) with an increasing CH4 flow was observed. Then, the hardness and Raman results were correlated with the H content in the coatings, showing that these indirect methods can be used to find if there are variations in the H content with the increase in the CH4 flow. Finally, the adhesion and tribological performance of the coatings were evaluated. No significant differences were found in the adhesion as a function of the H content. The tribological properties presented a slight improving trend with the increase in the H content with a decrease in the wear rate and friction.

Study of Hydroxyapatite-coated High-strength Biodegradable Magnesium-based Alloy in Repairing Fracture Damage in Rats.

Hydroxyapatite (HA) coating can improve the degradation rate and biological activity of metallic implants. This study aimed to fabricate a hydroxyapatite-coated ultrafine-grained biodegradable WE43 magnesium (HA/UFG-WE43 Mg) implant for repairing bone fractures. A hybrid approach, including parallel tubular-channel angular pressing (PTCAP) and physical vapour deposition (PVD) magnetron sputtering, was employed. The HA/UFG-WE43 Mg samples were tested in terms of their physicochemical and biological properties. The processed tubes exhibited ultrafine structures and the uniformity of microstructures improved following the two-pass PTCAP. The phase composition of the coating formed on UFG-WE43 Mg implant at 250 W for 90 min after heat treatment at 500°C for 60 min confirmed the presence of the HA characteristic peaks. Rat skeletal muscle cells were inoculated on the specimens and cultured for 1, 2, 6, 12, and 24 h, followed by evaluation of cell adhesion and morphology. The growth rates of cells were examined by the Cell Counting Kit8 (CCK-8) and cell survival was observed after 3 days of culture by fluorescence microscopy. The concentration of Mg ions in the blood of rats on 1, 3, 5, 7, and 15 days showed a reduction in Mg concentration after deposition of HA. Combination of PTCAP processing followed by surface modification led to tibial fracture healing, and histological analysis of implanted areas demonstrated an efficient biodegradation of the implanted material and a moderate inflammatory reaction.

Real-time monitoring of plasma synthesis of functional materials by high power impulse magnetron sputtering and other PVD processes: towards a physics-constrained digital twin

Plasma synthesis of thin films by physical vapour deposition (PVD) enables the creation of materials that drive significant innovations in modern life. High value manufacturing demand for tighter quality control and better resource utilisation can be met by a digital twin capable of modelling the deposition process in real time. Optical emission spectroscopy (OES) was combined with process parameters to monitor all stages of both high power impulse magnetron sputtering and conventional magnetron sputtering processes to provide a robust method of determining process repeatability and a reliable means of process control for quality assurance purposes. Strategies and physics-based models for the in-situ real-time monitoring of coating thickness, composition, crystallographic and morphological development for a CrAlYN/CrN nanoscale multilayer film were developed. Equivalents to the ion-to-neutral ratio and metal-to-nitrogen ratios at the substrates were derived from readily available parameters including the optical emission intensities of Cr I, N2 (C–B) and Ar I lines in combination with the plasma diffusivity coefficient obtained from the ratio of substrate and cathode current densities. These optically-derived equivalent parameters identified the deposition flux conditions which trigger the switch of dominant crystallographic texture from (111) to (220) observed in XRD pole figures and the development of coating morphology from faceted to dense for a range of magnetron magnetic field configurations. OES-based strategies were developed to monitor the progress of chamber evacuation, substrate cleaning and preventative chamber wall cleaning to support process optimisation and equipment utilisation. The work paves the way to implementation of machine learning protocols for monitoring and control of these and other processing activities, including coatings development and the use of alternative deposition techniques. The work provides essential elements for the creation of a digital twin of the PVD process to both monitor and predict process outcomes such as film thickness, texture and morphology in real time.

DLC-Coated Thermoplastics: Tribological Analyses under Lubricated Rolling-Sliding Conditions

The goal of this work is to evaluate the potential of diamond-like carbon (DLC) coatings on thermoplastic polymers for friction and wear reduction in highly stressed rolling–sliding contacts. Therefore, hydrogen-containing DLC coatings were deposited on the polymer surface by a low-temperature high power pulsed magnetron sputtering (HPPMS) physical vapor deposition (PVD) process. The rolling-sliding contact between coated polyamide 66 (PA66) or coated polyether ether ketone (PEEK) against case-hardened steel 16MnCr5 is investigated in a twin-disk tribometer at normal loads up to FN = 1,000 N, sum velocities between 1 m/s ≤ vΣ ≤ 16 m/s and slip ratios up to s = 50%. Results show a friction reduction with the application of DLC on the considered polymers compared to uncoated polymers under specific lubrication conditions. High solid losses caused by the polymer’s internal damping properties dominate the temperature behavior of the polymer, even when coated with DLC. Regarding the wear behavior, DLC coatings show potential especially under severe mixed lubrication conditions with high-solid load portion and sliding. The knowledge gained about coated polymers can be used to improve the overall tribological performance in terms of friction and wear of thermoplastic machine elements like gears.

Study of Al–SiO2 Aesthetic Composite Coating on Orthodontic Metal Archwire

Nickel–titanium orthodontic wires (NTWs) play an essential role in orthodontic treatment. However, their corrosion and aesthetic properties limit their applications. To improve the aesthetic effects of nickel–titanium orthodontic archwires, we prepared aluminium–silicon dioxide (Al–SiO2) as a biocompatible layer coated onto the NTWs. The Al–SiO2 coating was first fabricated using physical vapor deposition magnetron sputtering, and its physicochemical and biocompatibility properties were investigated. Al–SiO2 layers were well coated on the NTWs. The corrosion currents in the nickel–titanium (NiTi) control, Al–SiO2-coated NiTi experimental, stainless steel (SS) control and Al–SiO2-coated SS experimental groups were 23.72 μA cm−2, 1.21 μA cm−2, 0.22 μA cm−2 and 0.06 μA cm−2, respectively. Al–SiO2-coated NTWs with reduced corrosion current density indicated that the preparation of Al–SiO2 coating on the surface of NiTi and SS could reduce the tendency of electrochemical corrosion. The friction coefficients of orthodontic wires in the NiTi control, NiTi experimental, SS control, and SS experimental groups were 0.68, 0.46, 0.58 and 0.45, respectively. A low friction coefficient was observed in the Al–SiO2-coated NTWs, and the reduced friction coefficient improved the efficiency of orthodontics. Furthermore, the excellent biocompatibility of the NTWs and SS coated with Al–SiO2 indicates that Al–SiO2 as a novel aesthetic layer could improve the physicochemical properties of NTW and SS without causing cytotoxicity, which has considerable potential for modification of NTW and SS surfaces.

Hydrogen-free Cu: Amorphous-C: N Coating on TC4 Titanium Alloy: The Role of Gas Ratio on Mechanical and Antibacterial Potency

Ti-6Al-4V alloy, also called TC4, substrates are sputter-deposited by Cu: amorphous-C: N (Cu:a-C:N) thin coatings using planar magnetron sputtering physical vapor deposition device. Mixtures of argon and nitrogen at different ratios are selected as the sputtering atmosphere, and no hydrocarbon gas is used. Correlation of microstructure, morphology, surface properties, antibacterial characteristics, and mechanical performance of the coatings to the N2/Ar ratio are discussed. The outcomes from Raman spectroscopy confirm the construction of the DLC (Diamond Like Carbon) phase in the microstructure of the coatings. The thin coatings synthesized at higher N2/Ar ratios show more increased amount of sp 3 hybridization, improved wettability, higher internal stress, and enhanced mechanical properties, i.e., higher hardness. However, these are accompanied by lower antibacterial performance. Plastic hardness (H) value of the thin coatings increased from about 2 GPa to 13 GPa by increasing N2/Ar ratio. However, bacterial reduction percent of the thin coatings decreased from 100 to 65% as N2/Ar ratio increased. The resultant outcomes reveal the critical role of the N2/Ar ratio on tailoring the antibacterial properties of Cu: a-C: N thin coatings as well as mechanical ones.

Biocompatibility and antibacterial properties of TiCu(Ag) thin films produced by physical vapor deposition magnetron sputtering

Mechanical robustness, biocompatibility, and antibacterial performance are key features for materials suitable to be used in tissue engineering applications. In this work, we investigated the link existing between structural and functional properties of TiCu(Ag) thin films deposited by physical vapor deposition magnetron sputtering (MS-PVD) on Si substrates. Thin films were characterized by X-ray diffraction (XRD), nanoindentation, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The TiCu(Ag) films showed complete amorphous structure and improved mechanical properties in comparison with pure Ti films. However, for contents in excess of 20% Ag we observed the appearance of nanometric Ag crystallite. The TiCu(Ag) thin films displayed excellent biocompatibility properties, allowing adhesion and proliferation of the human fibroblasts MRC-5 cell line. Moreover, all the investigated TiCu(Ag) alloys display bactericidal properties, preventing the growth of both Pseudomonas aeruginosa and Staphylococcus aureus. Results obtained from biological tests have been correlated to the surface structure and microstructure of films. The excellent biocompatibility and bactericidal properties of these multifunctional thin films opens to their use in tissue engineering applications.

Friction and Wear Behavior of a Physical Vapor Deposition Coating Studied Using a Micro-Scratch Technique

Abstract CrSiN coating was deposited by physical vapor deposition (PVD) magnetron sputtering on XC100 steel substrate. Microstructural and morphological properties were studied using scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and atomic force microscopy (AFM). Nanoindentation and scratching experiments were conducted to study the mechanical and adhesion behavior. Multi-pass scratch tests were conducted under different sliding conditions. Results showed that CrSiN coating has a dense and compact nanocomposite microstructure consisting of CrN nanocrystallites and SiN amorphous matrix. The CrSiN thin film exhibit hardness and Young's modulus of 30.52 ± 1.85 GPa and 338.32 ± 13.5 GPa, respectively. The H/E, H3/E2, and 1/HE2 ratios were also calculated (H/E ≈ 0.09, H3/E2 ≈ 0.024, and 1/HE2 ≈ 2.86 × 10−07) and used to predict and assess the elastic/plastic and wear resistance. Critical loads LC1, LC2, and LC3 obtained with scratch test, were, respectively, 11.5 ± 0.12, 16.6 ± 0.23, and 20 ± 0.35 N. Multi-pass scratch were analyzed and the friction coefficient (COF), the damage mechanism, and wear volume were determined. The use of an energetic approach allowed to determine the energetic wear coefficient. CrSiN coating revealed a low friction coefficient (around 0.1) and a low energetic wear coefficient (6.3 × 10−7 mm3/N.m). In addition, it was found that multi-pass scratch method has the potential to extract relevant information about wear behavior.

Self-lubricating triboactive (Cr,Al)N+Mo:S coatings for fluid-free applications

Within this study, self-lubricating and triboactive (Cr,Al)N+Mo:S coatings were developed and investigated for the deposition on components in a low-temperature physical vapor deposition (PVD) hybrid process. Therefore, direct current magnetron sputtering (dcMS) and high power pulse magnetron sputtering (HPPMS) PVD were combined by using an industrial coating machine. Hereby, it was possible to deposit dense and smooth triboactive, self-lubricating nitride coatings with different chemical compositions and architectures on 16MnCr5E samples. Two coating architectures, a matrix monolayer and a graded coating structure, were developed to evaluate the effect on the tribological behavior. The morphology and coating thickness were analyzed by means of scanning electron microscopy (SEM). Furthermore, the indentation hardness and modulus of indentation as well as the compound adhesion between substrate materials and coating were analyzed. Tribological analyses of (Cr,Al)N+Mo:S-coated and uncoated samples were conducted under fluid-free friction regime at room temperature T = (20 ± 3) °C, a velocity v = 0.1 m/s and a distance s = 1000 m by varying the Hertzian contact pressure from 400 MPa ≤ pH ≤ 1300 MPa against steel counterparts, 100Cr6, in a pin-on-disk (PoD) tribometer. The graded coating architecture of (Cr,Al)N+Mo:S enabled a significant wear and friction reduction. Furthermore, Raman analyses prove the formation of solid lubrication tribofilm containing MoS2, MoO3 MoO2 and MoxOy at the toplayer of a graded (Cr,Al)N+Mo:S coating, which are responsible for the improved tribological behavior.

Synthesis and Characterization of Ti-Nb Alloy Films Obtained by Magnetron Sputtering and Low-Energy High-Current Electron Beam Treatment.

The aim of the present work is to investigate the synthesis of Ti–Nb alloy films obtained by the physical vapor deposition (PVD) magnetron sputtering of Nb films on Ti substrates, followed by low-energy high-current electron beam (LEHCEB) alloying treatment. Ti–Nb alloys were synthetized under two different regimes, one by varying the deposited amount of Nb (from 25 to 150 nm) and treating samples with low applied voltages and a number of pulses (three pulses at either 20 or 25 kV), the second by setting the amount of Nb (100 nm) and alloying it at a higher applied voltage with a different number of pulses (from 10 to 50 at 25 and 30 kV). The synthetized Ti–Nb alloys were characterized by XRD and GDOES for phase identification and chemical composition; SEM and optical microscopy were employed for morphology evaluation; compositional investigation was done by EDS analysis and mechanical properties were evaluated by microindentation tests. LEHCEB treatment led to the formation of metastable phases (α′, α″ and β) which, together with the grain refinement effect, was responsible for improved mechanical properties.

Influence of the Silver Content on Mechanical Properties of Ti-Cu-Ag Thin Films.

In this work, the ternary titanium, copper, and silver (Ti-Cu-Ag) system is investigated as a potential candidate for the production of mechanically robust biomedical thin films. The coatings are produced by physical vapor deposition—magnetron sputtering (MS-PVD). The composite thin films are deposited on a silicon (100) substrate. The ratio between Ti and Cu was approximately kept one, with the variation of the Ag content between 10 and 35 at.%, while the power on the targets is changed during each deposition to get the desired Ag content. Thin film characterization is performed by X-ray diffraction (XRD), nanoindentation (modulus and hardness), to quantitatively evaluate the scratch adhesion, and atomic force microscopy to determine the surface topography. The residual stresses are measured by focused ion beam and digital image correlation method (FIB-DIC). The produced Ti-Cu-Ag thin films appear to be smooth, uniformly thick, and exhibit amorphous structure for the Ag contents lower than 25 at.%, with a transition to partially crystalline structure for higher Ag concentrations. The Ti-Cu control film shows higher values of 124.5 GPa and 7.85 GPa for modulus and hardness, respectively. There is a clear trend of continuous decrease in the modulus and hardness with the increase of Ag content, as lowest value of 105.5 GPa and 6 GPa for 35 at.% Ag containing thin films. In particular, a transition from the compressive (−36.5 MPa) to tensile residual stresses between 229 MPa and 288 MPa are observed with an increasing Ag content. The obtained results suggest that the Ag concentration should not exceed 25 at.%, in order to avoid an excessive reduction of the modulus and hardness with maintaining (at the same time) the potential for an increase of the antibacterial properties. In summary, Ti-Cu-Ag thin films shows characteristic mechanical properties that can be used to improve the properties of biomedical implants such as Ti-alloys and stainless steel.

Optimisation of Mechanical Properties of Gradient Zr-C Coatings.

One of the key components of the designing procedure of a structure of hard anti-wear coatings deposited via Physical Vapour Deposition (PVD) is the analysis of the stress and strain distributions in the substrate/coating systems, initiated during the deposition process and by external mechanical loads. Knowledge of residual stress development is crucial due to their significant influence on the mechanical and tribological properties of such layer systems. The main goal of the work is to find the optimal functionally graded material (FGM) coating’s structure, composed of three functional layers: (1) adhesive layer, providing high adhesion of the coating to the substrate, (2) gradient load support and crack deflection layer, improving hardness and enhancing fracture toughness, (3) wear-resistant top layer, reducing wear. In the optimisation procedure of the coating’s structure, seven decision criteria basing on the state of residual stresses and strains in the substrate/coating system were proposed. Using finite element simulations and postulated criteria, the thickness and composition gradients of the transition layer in FGM coating were determined. In order to verify the proposed optimisation procedure, Zr-C coatings with different spatial distribution of carbon concentration were produced by the Reactive Magnetron Sputtering PVD (RMS PVD) method and their anti-wear properties were assessed by scratch test and ball-on-disc tribological test.

Fatigue behaviour and mechanical properties of PVD CrSiN coating using cyclic nanoindentation

ABSTRACT In this study, chromium nitride-based CrSiN coatings were deposited by PVD (physical vapour deposition) magnetron sputtering on XC100 steel substrate. Mechanical properties of CrSiN were investigated using monotonic nanoindentation test. It was found that CrSiN coatings had excellent mechanical properties, hardness of 30.52 ± 1.85 GPa and elastic modulus of 338.32 ± 13.5 GPa. Fatigue behaviour of CrSiN thin film was studied using multi-cycles nanoindentation test. Under cyclic nanoindentation, the unloading–reloading paths produced the hysteresis loops which reflect a fatigue effect. In addition, the increase in the number of indentation cycle induced the degradation of the film mechanical proprieties and the evolution of damage mechanism. The similarity between the indentation fatigue depth propagation and the conventional fatigue crack growth was exploited based on Manson–Coffin law to extract the fatigue properties of CrSiN coating. The obtained fatigue ductility coefficient was and the fatigue ductility exponent was c = −0.96.