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Results concerning the optical characterization of two inhomogeneous polymer-like thin films deposited by the plasma enhanced chemical vapor deposition onto silicon single crystal substrates are presented. One of these films is deposited onto a smooth silicon surface while the latter film is deposited on a randomly rough silicon surface with a wide interval of spatial frequencies. A combination of variable-angle spectroscopic ellipsometry and spectroscopic reflectometry applied at near-normal incidence are utilized for characterizing both the films. An inhomogeneity of the films is described by the method based on multiple-beam interference of light and method replacing inhomogeneous thin films by multilayer systems. Homogeneous transition layers between the films and substrates are considered. The Campi–Coriasso dispersion model is used to express spectral dependencies of the optical constants of the polymer-like films and transition layers. A combination of the scalar diffraction theory and Rayleigh–Rice theory is used to include boundary roughness into formulae for the optical quantities of the rough polymer-like film. Within the optical characterization, the spectral dependencies of the optical constants at the upper and lower boundaries of both the polymer-like films are determined together with their thickness values and profiles of the optical constants. Roughness parameters are determined for the rough film. The values of the roughness parameters are confirmed by atomic force microscopy. Moreover, the optical constants and thicknesses of both the transition layers are determined. A discussion of the achieved results for both the polymer-like films and transition layers is performed.

Pathogenic microbes, such as bacteria and viruses, can spread quickly via contaminated surfaces. Most of these pathogenic microorganisms can survive on surfaces for a long time. Touching these surfaces can lead to the transmission of the microorganisms to the human body and cause serious illnesses. ZrN-Cu coatings containing different amounts of Cu were deposited using an industrial PVD system, and their ability to inhibit bacteria and inactivate the SARS-CoV-2 virus was tested. Microstructural studies showed the formation of two distinct ZrN and Cu phases when Cu content was sufficiently high. Hardness and elastic modulus were inversely proportional to the Cu content. The coatings showed outstanding bactericidal properties against Escherichia coli and Pseudomonas aeruginosa, especially when Cu content was more than 12 at.% and exposure time was longer than 40 min. The coatings, however, did not exhibit any significant virucidal properties. Good mechanical properties, along with excellent antibacterial effects, make these coatings suitable for use as self-sanitizing surfaces on objects that people regularly touch and that are prone to bacterial contamination. Their use would thus allow for only minimal transmission or multiplication of bacteria, and the treated surface would not serve as another source of infection.

In this study, a novel approach for characterizing the optical properties of inhomogeneous thin films is presented, with a particular focus on samples exhibiting absorption in some part of the measured spectral range. Conventional methods of measuring the samples only from the film side can be limited by incomplete information at the lower boundary of the film, leading to potentially unreliable results. To address this issue, depositing the thin films onto non-absorbing substrates to enable measurements from both sides of the sample is proposed. To demonstrate the efficacy of this approach, a combination of variable-angle spectroscopic ellipsometry and spectrophotometry at near-normal incidence was employed to optically characterize three inhomogeneous polymer-like thin films. The spectral dependencies of the optical constants were modeled using the Kramers–Kronig consistent model. It was found that it is necessary to consider thin, weakly absorbing transition layers between the films and the substrates. The obtained results show excellent agreement between the fits and the measured data, providing validation of the structural and dispersion models, as well as the overall characterization procedure. The proposed approach offers a method for optically characterizing a diverse range of inhomogeneous thin films, providing more reliable results when compared to traditional one-sided measurements.

Coated components used in industry are often exposed to repetitive dynamic impact load. The dynamic impact test is a suitable method for the study of thin protective coatings under such conditions. Aim of this paper is to describe the method of dynamic impact testing and the novel concepts of evaluation of the impact test results, such as the impact resistance and the impact deformation rate. All of the presented results were obtained by testing two W-B-C coatings with different C/W ratio. Different impact test results are discussed with respect to the coatings microstructure, the chemical and phase composition, and the mechanical properties. It is shown that coating adhesion to the HSS substrate played a crucial role in the coatings’ impact lifetime.

An inhomogeneous polymer-like thin film was deposited by the plasma enhanced chemical vapor deposition onto silicon single-crystal substrate whose surface was roughened by anodic oxidation. The inhomogeneous thin film with randomly rough boundaries was created as a result. This sample was studied using the variable-angle spectroscopic ellipsometry and spectroscopic reflectometry. The structural model including the inhomogeneous thin film, transition layer, and identically rough boundaries was used to process the experimental data. The scalar diffraction theory was used to describe the influence of roughness. The influence of the scattered light registered by the spectrophotometer due to its finite acceptance angle was also taken into account. The thicknesses and optical constants of the inhomogeneous thin film and the transition layer were determined in the optical characterization together with the roughness parameters. The determined rms value of the heights of roughness was found to be in good agreement with values obtained using AFM. The results of the optical characterization of the studied inhomogeneous thin film with rough boundaries were also verified by comparing them with the results of the optical characterization of the inhomogeneous thin film prepared using the same deposition conditions but onto the substrate with a smooth surface. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Electrical resistivity (4.2–800 K), Seebeck coefficient (300–800 K), specific heat (2–110 K), Vickers hardness, elastic moduli (RT) were defined for single-phase nonstoichiometric compounds: Ti2.13Ni2Sn0.87, Zr2.025Ni2Sn0.975, and Hf2.055Ni2Sn0.945.

In this study mid-frequency pulsed-DC magnetron sputtering was used to deposit W-B-C coatings. The effect of coating composition and the deposition parameters on the structure, mechanical and tribological properties of the coatings was investigated. The broad diffraction peaks in the X-ray diffractogram indicated the amorphous to nanocrystalline nature of the coatings. The hardness of the coatings ranged from 22.6 to 26.2 GPa. The coatings prepared at the elevated temperature of 500 degrees C exhibited greater hardness compared to the coatings prepared at the ambient temperature. The amount of W in the coatings was the main parameter influencing the friction coefficient with a higher W content leading to a higher friction coefficient. The coatings prepared at 500 degrees C showed lower wear in tribological measurements due to their higher hardness compared to the coatings prepared at ambient temperature. The friction coefficient decreased as the testing temperature increased beyond 500 degrees C. XRD analyses after the high temperature tests have shown that this decrease was due to the formation of W-O Magneli phases, which acted as a solid-state lubricant.

Polyoxazoline thin coatings were deposited on glass substrates using atmospheric pressure plasma polymerization from 2-ethyl-2-oxazoline vapours. The plasma polymerization was performed in dielectric barrier discharge burning in nitrogen at atmospheric pressure. The thin films stable in aqueous environments were obtained at the deposition with increased substrate temperature, which was changed from 20◦ C to 150◦ C. The thin film deposited samples were highly active against both S. aureus and E. coli strains in general. The chemical composition of polyoxazoline films was studied by FTIR and XPS, the mechanical properties of films were studied by depth sensing indentation technique and by scratch tests. The film surface properties were studied by AFM and by surface energy measurement. After tuning the deposition parameters (i.e., monomer flow rate and substrate temperature), stable films, which resist bacterial biofilm formation and have cell-repellent properties, were achieved. Such antibiofouling polyoxazoline thin films can have many potential biomedical applications. © MDPI AG. All rights reserved., Czech Science FoundationGrant Agency of the Czech Republic [GACR 19-15240S]; Ministry of Defence of the Czech Republic

This research was devoted to studying the influence of the taper angle on the micro-compression of micro-pillars fabricated from near-amorphous and nanocrystalline Mo-B-C coatings. A series of micro-pillars with a taper angle between 4–14° was fabricated by focused ion beam technique. The deformation mechanism was found to be dependent on the taper and, also, on the crystallinity of the coating. In order to obtain correct values of yield strength and Young’s modulus, three empirical models of stress correction were experimentally tested, and the results were compared with nanoindentation measurements. It was shown that the average stress correction model provided comparable results with nanoindentation for the yield strength for taper angles up to ~10°. On the other hand, the average radius or area model gave the most precise results for Young’s modulus if the taper angle was

The current work aimed to characterize the morphology, chemical, and mechanical properties of Pt and PtTi thin films deposited via thermionic vacuum arc (TVA) method on glass and silicon substrates. The deposited thin films were characterized by means of a scanning electron microscope technique (SEM). The quantitative elemental microanalysis was done using energy-dispersive X-ray spectroscopy (EDS). The tribological properties were studied by a ball-on-disc tribometer, and the mechanical properties were measured using nanoindentation tests. The roughness, as well as the micro and nanoscale features, were characterized using atomic force microscopy (AFM) and transmission electron microscopy (TEM). The wettability of the deposited Pt and PtTi thin films was investigated by the surface free energy evaluation (SFE) method. The purpose of our study was to prove the potential applications of Pt-based thin films in fields, such as nanoelectronics, fuel cells, medicine, and materials science.

In this paper the complete optical characterization of an inhomogeneous polymer-like thin film of SiO x C y H z exhibiting a thickness non-uniformity and transition layer at the boundary between the silicon substrate and this film is performed using variable angle spectroscopic ellipsometry. The Campi-Coriasso dispersion model was utilized for describing the spectral dependencies of the optical constants of the SiO x C y H z thin film and transition layer. The multiple-beam interference model was used for expressing inhomogeneity of the SiO x C y H z thin film. The thickness non-uniformity of this film was taken into account by means of the averaging of the elements of the Mueller matrix performed using the thickness distribution for the wedge-shaped non-uniformity. The spectral dependencies of the optical constants of the SiO x C y H z thin film at the upper and lower boundaries together with the spectral dependencies of the optical constants of the transition layer were determined. Furthermore, the thickness values of the SiO x C y H z film and transition layer, profiles of the optical constants of the SiO x C y H z thin film and the rms value of local thicknesses corresponding to its thickness non-uniformity were determined. Thus, all the parameters characterizing this complicated film were determined without any auxiliary methods.

In this work, thermal stability and mechanical properties of Ti/Ni multilayer thin films were studied. The multilayer thin films were synthesised by alternately depositing Ti and Ni layers using magnetron sputtering. The thickness of constituent layers of Ti and Ni varied from 1.7 nm to 10 nm, and one coating was deposited by simultaneous sputtering of both targets. Single crystalline silicon was used as a substrate. The effects of thermal treatment on the mechanical properties were studied using nanoindentation and discussed in relation to microstructure evaluated by X-ray diffraction. Annealing was carried out under low-pressure conditions for 2 hours in the range of 100–800°C.

Plasma-polymerized SiOxCyHz thin films have been playing an important role in many research studies due to their wide range of applications. These materials are perspective for industrial applications as protective coatings of metals or plastic substrates, anti-reflection coatings for solar cells, low-k dielectrics for microelectronics, water-repellent barrier films etc. Materials based on organosilicon precursors prepared by PECVD technique have become interesting for bioapplications in recent years as well due to their ability to optimize protein adsorption and cell attachment. These coatings have a great potential e.g. in BioMEMS microfabrication or treatment of biosensors and surfaces of medical implants.In the present study, low pressure RF capacitive coupled discharge in mixture of trimethylsilyl acetate (TMSA) monomer with oxygen or argon was used to create hydrophobic SiOxCyHz coatings. This study is focused primarily on research of properties of resulting coatings (chemical composition, mechanical properties, optical properties, surface wettability and surface structure) in dependence on discharge parameters. Properties of created thin films were examined in dependence on the ratio of TMSA monomer and carrier gas flow rates during the deposition process. Influence of used carrier gas (O2 or Ar) on growth of TMSA-based plasma polymers is discussed in this study as well.

In the present work plasma-polymer nanocomposite thin films were prepared under dusty plasma conditions in capacitively coupled RF discharges. The main focus was on the study of the formation of the organosilicon plasma polymers and their growth. The plasma polymers were grown heterogeneously in form of polymeric particles arising from the discharge volume which incorporated into the amorphous organosilicon polymeric film growing on the silicon and glass substrates. The created nanocomposite structure had very beneficial influence on the film properties. The films showed very interesting mechanical and surface properties. Variation in deposition conditions enabled us to vary the surface free energy of the films. The mechanical properties of the films were studied using nanoindentation technique and the surface structure was studied using atomic force microscopy. The atomic composition and chemical structure of the films were studied studied using XPS and FTIR techniques. The surface free energy of the films was studied using contact angle measuring techniques.

In the present work we focused on the development of a low pressure capacitively coupled radio-frequency PECVD reactor for preparation of plasma-polymer thin films from organosilazane precursors. The dependence of the film growth from hexamethyldisilazane (HMDSZ, SiN2C6H19) and oxygen containing mixtures on the deposition parameters was studied. The time evolution of the negative self bias voltage on the thin film growth was studied. It was found, that the changes in the self bias voltage significantly influenced the surface structure and the properties of the growing films. The mechanical properties of the films were studied using nanoindentation technique and the surface structure was studied using atomic force microscopy (AFM).

Nanocomposite polymer coatings combine attractive functionalities from the combination of organic matrix coatings and inorganic nanoparticles which allows to acquire unique properties. They can be tailored for specific needs by modifying optical, mechanical, electronic, magnetic and other properties, which may differ significantly from the properties of the bulk form. In order to study the role of the incorporated nanoparticles, topography is of fundamental importance. Its relation to the deposition parameters, however, is far from trivial. Suitable statistical parameters, which capture the essential traits of the sample but are not oversensitive to local variations are needed. Roughness e.g. is a well-established, popular statistical parameter but is not sufficient to describe the topography. Parameters which describe lateral distances should be included as well. In order to ensure the same processing for multiple samples the data processing should also require as little user input as possible. As a wide range of samples must be characterized, time demands for the characterization of a single sample should also be considered. We present a systematic atomic force microscopy study of a series of nanocomposite polymer coatings with topographies including spherical particles and snake-like structures of different length scales. Different statistical parameters, their dependence on measurement settings and related uncertainties are addressed.

Thin solid films based on organosilicon monomers are perspective in many branches of industry as well as for bioapplications. In the present study, plasma of RF capacitively coupled glow discharge in gaseous mixture of trimethylsilyl acetate (TMSA) monomer and methane was used to create SiOxCyHz coatings. This study monitors properties of resulting thin films (surface chemistry, wettability, surface structure and mechanical properties) in dependency on deposition parameters. The main subject of the presented research is the investigation of the relationship between the above-mentioned properties of prepared organosilicon coatings and the flow rate ratio of TMSA monomer and CH4 carrier gas applied during deposition process.

Nanoindentation has become a popular tool for the exploration of mechanical properties of materials at the nanoscale. However, calibration and traceability issues are often neglected, making the direct comparison of results between different instruments difficult. The direct calibration of the sensors is challenging and requires dedicated instruments leaving indirect calibration as the only option to ordinary users. However, indirect calibration compares only the resulting hardness or modulus of the reference sample and the measured sample. Therefore, it cannot distinguish the source of errors, such as errors in the depth and load sensors, errors in the reference sample properties, contamination of the tip or sample, wear of tip and others.In this contribution we explore the possibility of using measurements of indents by atomic force microscopy for the verification of the depth sensor. Measurements for different nanoindentation devices are presented and compared with a focus on the uncertainties of the method.

We report on the influence of post-printing curing on the physico-chemical properties of silica-bonded particulate titania photocatalytic layers. Ink consisting of commercial titania nanoparticles and a novel siloxane binder was patterned by inkjet printing. Printed layers were mineralized by three processes: thermal annealing by convection heating in an electric furnace, UV-curing with a high pressure mercury vapour lamp, and atmospheric plasma treatment in a coplanar dielectric barrier discharge. The influence of these processes on the extend of the binder mineralization and resulting physicochemical properties, charge generation and transport as well as photocatalytic activity was investigated. All curing methods proved to be capable to mineralize the binder but atmospheric plasma curing stands out as the fastest one enabling a direct implementation into roll-to-roll fabrication processes.

Preparation of coatings simultaneously exhibiting high hardness and enhanced fracture resistance is a hot topic, as nowadays used ceramic protective coatings show difficulties to cope with increased demands due to their inherent brittleness. Material exhibiting seemingly contradictory combination of mechanical properties like high hardness and moderate ductility enhancing the fracture resistance - was recently predicted by ab initio calculations in the crystalline X2BC system. The presented study is focused on the study of the influence of the C/W ratio on the microstructure, the content of different chemical bonds and the mechanical properties of WBC coatings prepared by magnetron sputtering at moderate temperature.

State-of-the-art protective coatings often suffer from brittleness. Therefore, the coatings are intensively sought which would simultaneously exhibit high hardness and stiffness with moderate ductility and fracture resistance. In this paper, we report on the nanostructure designing of coatings containing metal, boron, and carbon enabling the simultaneous presence of stiff boridic and carbidic bonds together with weaker metallic bonds to provide coatings with these desirable properties. Three designs are presented with different relative amounts of nanocrystalline and amorphous phases, ranging from near-amorphous to prevalently crystalline microstructure. All presented coatings exhibit an unusual combination of high fracture resistance and high hardness that cannot be achieved with state-of-the-art protective coatings. Indentation tests at high loads revealed that no cracks are present at the surface of the investigated coatings while state-of-the-art ceramic protective coatings already exhibit significant cracking. Cracks in the bulk of the presented coating are detected only when the deformation is so severe that the substrate itself fails.

The importance of the often omitted running-in phase of tribological testing was studied on hard nc-TiC/a-C:H coating system selected as a representative of protective tribological coatings. The tribological measurements were periodically interrupted and the counterpart ball was replaced by a new one after every interrupted test to simulate machining applications, where the coatings are repeatedly in contact with a new material. The changes in the coefficient of friction and the wear rate of the counterpart ball were found to be dependent mainly on the roughness of the coating at any stage. It was found out that after substantial smoothening of the wear track of the measured coating, the coefficient of friction stabilized at the steady-state value attained in an uninterrupted long tribotest. This steady state value was reached at the very beginning of the test and initial instabilities in the coefficient of friction were no longer observed. It was also concluded that only after the nc-TiC/a-C:H coating gets smoothened enough within the wear track, the steady-state coefficient of friction can describe even applications where the counterpart is being periodically replaced by a new one.

Nanocomposite nc-TiC/a-C:H thin films exhibit unique combination of mechanical properties, high hardness, low friction, and wear. Selective doping by weak-carbide forming element can be used in order to specifically design the physical and chemical properties of nc-TiC/a-C:H coatings. In this paper we report on an effect of nickel addition on structure and hardness of the nc-TiC/a-C:H coatings. The effect of Ni alloying on the coating structure under conditions of DCMS and HiPIMS depositions was studied. The coating structure was correlated with the coating hardness. The grain size, the grain carbon vacancy concentration, and the mean grain separation were found to be the key parameters determining the coating hardness. Ni doping proved to have a significant effect on the coating microstructure which resulted in changes of the hardness of the deposited coatings.

Polyoxazolines are a new promising class of polymers for biomedical applications. Antibiofouling polyoxazoline coatings can suppress bacterial colonization of medical devices, which can cause infections to patients. However, the creation of oxazoline-based films using conventional methods is difficult. This study presents a new way to produce plasma polymerized oxazoline-based films with antibiofouling properties and good biocompatibility. The films were created via plasma deposition from 2-methyl-2-oxazoline vapors in nitrogen atmospheric pressure dielectric barrier discharge. Diverse film properties were achieved by increasing the substrate temperature at the deposition. The physical and chemical properties of plasma polymerized polyoxazoline films were studied by SEM, EDX, FTIR, AFM, depth-sensing indentation technique, and surface energy measurement. After tuning of the deposition parameters, films with a capacity to resist bacterial biofilm formation were achieved. Deposited films also promote cell viability.

We combine theoretical and experimental tools to study elastic properties of Fe-Al-Ti superalloys. Focusing on samples with chemical composition Fe 71 Al 22 Ti 7 , we use transmission electron microscopy (TEM) to detect their two-phase superalloy nano-structure (consisting of cuboids embedded into a matrix). The chemical composition of both phases, Fe 66 . 2 Al 23 . 3 Ti 10 . 5 for cuboids and Fe 81 Al 19 (with about 1% or less of Ti) for the matrix, was determined from an Energy-Dispersive X-ray Spectroscopy (EDS) analysis. The phase of cuboids is found to be a rather strongly off-stoichiometric (Fe-rich and Ti-poor) variant of Heusler Fe 2 TiAl intermetallic compound with the L2 1 structure. The phase of the matrix is a solid solution of Al atoms in a ferromagnetic body-centered cubic (bcc) Fe. Quantum-mechanical calculations were employed to obtain an insight into elastic properties of the two phases. Three distributions of chemical species were simulated for the phase of cuboids (A2, B2 and L2 1 ) in order to determine a sublattice preference of the excess Fe atoms. The lowest formation energy was obtained when the excess Fe atoms form a solid solution with the Ti atoms at the Ti-sublattice within the Heusler L2 1 phase (L2 1 variant). Similarly, three configurations of Al atoms in the phase of the matrix with different level of order (A2, B2 and D0 3 ) were simulated. The computed formation energy is the lowest when all the 1st and 2nd nearest-neighbor Al-Al pairs are eliminated (the D0 3 variant). Next, the elastic tensors of all phases were calculated. The maximum Young&rsquo, s modulus is found to increase with increasing chemical order. Further we simulated an anti-phase boundary (APB) in the L2 1 phase of cuboids and observed an elastic softening (as another effect of the APB, we also predict a significant increase of the total magnetic moment by 140% when compared with the APB-free material). Finally, to validate these predicted trends, a nano-scale dynamical mechanical analysis (nanoDMA) was used to probe elasticity of phases. Consistent with the prediction, the cuboids were found stiffer.

A common approach to non-uniformity is to assume that the local thicknesses inside the light spot are distributed according to a certain distribution, such as the uniform distribution or the Wigner semicircle distribution. A model considered in this work uses a different approach in which the local thicknesses are given by a polynomial in the coordinates x and y along the surface of the film. An approach using the Gaussian quadrature is very efficient for including the influence of the non-uniformity on the measured ellipsometric quantities. However, the nodes and weights for the Gaussian quadrature must be calculated numerically if the non-uniformity is parameterized by the second or higher degree polynomial. A method for calculating these nodes and weights which is both efficient and numerically stable is presented. The presented method with a model using a second-degree polynomial is demonstrated on the sample of highly non-uniform polymer-like thin film characterized using variable-angle spectroscopic ellipsometry. The results are compared with those obtained using a model assuming the Wigner semicircle distribution.

Nanocomposite nc-TiC/a-C:H coatings exhibit a unique combination of mechanical properties such as high hardness, and low friction and wear. These physical and mechanical properties make those coatings attractive for application in industry. However, the properties of the whole coating/substrate system such as adhesion of the coating to substrate and its response on repeated impact loading known such as dynamic impact wear are also important for industrial applications. Thus, this paper is focused on the adhesion and the dynamic impact wear of nc-TiC/a-C:H coatings prepared by the hybrid PVD-PECVD process. Two series of nc-TiC/a-C:H coatings with a different amount of carbon were deposited onto commonly used industrial cemented tungsten carbide substrates using DC magnetron sputtering (DCMS) and the high power impulse magnetron sputtering (HiPIMS) of a titanium target in argon and acetylene mixture atmosphere. Both series of coatings were analysed using a scratch test and dynamic impact tester with an impact load of 600 N. The HiPIMS prepared coatings exhibited lower thickness and lower thicknesses of the Ti adhesive interlayers between the substrates and coatings than the DCMS prepared coatings. Thus, the adhesion and the impact wear of both series were discussed separately. These properties were discussed with respect to the coating microstructure, phase composition and mechanical properties such as the hardness H, the effective elastic modulus E, and the H/E and H-3/E-2 ratios. The scratch adhesion of coatings depended on the H-3/E-2 ratio and coating microstructure, hardness and surface roughness. The impact wear of the nc-TiC/a-C:H coatings depended on the H/E ratio and coating microstructure.

Nanostructured C-Ag thin films of 200 nm thickness were successfully synthesized by the Thermionic Vacuum Arc (TVA) method. The influence of different substrates (glass, silicon wafers, and stainless steel) on the microstructure, morphology, and mechanical properties of nanostructured C-Ag thin films was characterized by High-Resolution Transmission Electron Microscopy (HRTEM), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and TI 950 (Hysitron) nanoindenter equipped with Berkovich indenter, respectively. The film’s hardness deposited on glass (HC-Ag/Gl = 1.8 GPa) was slightly lower than in the case of the C-Ag film deposited on a silicon substrate (HC-Ag/Si = 2.2 GPa). Also the apparent elastic modulus Eeff was lower for C-Ag/Gl sample (Eeff = 100 GPa) than for C-Ag/Si (Eeff = 170 GPa), while the values for average roughness are Ra=2.9 nm (C-Ag/Si) and Ra=10.6 (C-Ag/Gl). Using the modulus mapping mode, spontaneous and indentation-induced aggregation of the silver nanoparticles was observed for both C-Ag/Gl and C-Ag/Si samples. The nanocomposite C-Ag film exhibited not only higher hardness and effective elastic modulus, but also a higher fracture resistance toughness to the silicon substrate compared to the glass substrate.

X-B-C materials, where X is a transition metal such as Mo, W or Ta, have recently gained attention as possible materials for protective coatings used in material machining. In this study, a combinatorial approach was used to deposit a total of 182 coatings with a wide composition range using pulsed-DC magnetron sputtering. The coatings were prepared either in conditions, where a comparatively lower energy was delivered onto the growing coating, i.e. at ambient temperature and without applied bias, or in conditions where the coating received higher energy, i.e. at 500 °C with a bias voltage of −100 V, to study the effect of energy flow on the coating structure and properties. The coating structure was examined and four different types of diffractograms have been observed: amorphous, short range ordered, crystalline W and nanocrystalline WB2. No other crystalline phases were detected. The measured hardness of the coatings was between 9.7 and 29.7 GPa and was independent of the carbon content, however, it increased with the boron content and decreased with the tungsten content in the composition region studied. The hardest coatings exhibited an amorphous structure. The effective elastic modulus ranged from 170 to 340 GPa and increased with the boron and tungsten contents. The highest moduli were obtained for coatings exhibiting a crystalline W phase. Coatings deposited at high energy flow to the growing coating generally exhibited higher hardness and comparable elastic modulus to their counterparts with a similar composition prepared without heating or bias.

This paper presents the results of the optical characterization of inhomogeneous thin films of polymer-like SiO x C y H z and non-stoichiometric silicon nitride SiN x. An efficient method combining variable angle spectroscopic ellipsometry and spectroscopic reflectometry applied at the near-normal incidence based on the multiple-beam interference model is utilized for this optical characterization. The multiple-beam interference model allows us to quickly evaluate the values of ellipsometric parameters and reflectance of the inhomogeneous thin films, which exhibit general profiles of their optical constants. The spectral dependencies of the optical constants of the inhomogeneous SiO x C y H z and SiN x thin films are determined using the Campi–Coriasso dispersion model. The profiles of the optical constants of these films can also be determined. Furthermore, the transition layers at the lower boundaries of the characterized films are also taken into account. Spectral dependencies of the optical constants of these transition layers are also determined using the Campi–Coriasso dispersion model.This paper presents the results of the optical characterization of inhomogeneous thin films of polymer-like SiO x C y H z and non-stoichiometric silicon nitride SiN x. An efficient method combining variable angle spectroscopic ellipsometry and spectroscopic reflectometry applied at the near-normal incidence based on the multiple-beam interference model is utilized for this optical characterization. The multiple-beam interference model allows us to quickly evaluate the values of ellipsometric parameters and reflectance of the inhomogeneous thin films, which exhibit general profiles of their optical constants. The spectral dependencies of the optical constants of the inhomogeneous SiO x C y H z and SiN x thin films are determined using the Campi–Coriasso dispersion model. The profiles of the optical constants of these films can also be determined. Furthermore, the transition layers at the lower boundaries of the characterized films are also taken into account. Spectral dependencies o...

Polymeric surfaces can benefit from functional modifications prior to using them for biological and/or technical applications. Surfaces considered for biocompatibility studies can be modified to gain beneficiary hydrophilic properties. For such modifications, the preparation of highly hydrophilic surfaces by means of plasma polymerization can be a good alternative to classical wet chemistry or plasma activation in simple atomic or molecular gasses. Atmospheric pressure plasma polymerization makes possible rapid, simple, and time-stable hydrophilic surface preparation, regardless of the type and properties of the material whose surface is to be modified. In this work, the surface of polypropylene was coated with a thin nanolayer of plasma-polymer which was prepared from a low-concentration mixture of propane-butane in nitrogen using atmospheric pressure plasma. A deposition time of only 1 second was necessary to achieve satisfactory hydrophilic properties. Highly hydrophilic, stable surfaces were obtained when the deposition time was 10 seconds. The thin layers of the prepared plasma-polymer exhibit highly stable wetting properties, they are smooth, homogeneous, flexible, and have good adhesion to the surface of polypropylene substrates. Moreover, they are constituted from essential elements only (C, H, N, O). This makes the presented modified plasma-polymer surfaces interesting for further studies in biological and/or technical applications.

Nanoindentation is a popular tool for the study of hardness and elasticity of materials at the nanoscale. However, the roughness of such samples may violate the basic assumptions under which these parameters can be evaluated. In this article we study the effects of roughness on the reduced modulus of contact. A systematic study using 3D FEA modeling to map the apparent modulus on a real rough surface as measured by AFM is presented. The requirements for the assessment of 2D modulus maps are compared to the requirements for the assessment of the average value and found to be much higher, approx. by a factor of ten. The possibility to use a simplified Hertzian model based on the local curvature is explored and found to give acceptable results, at least from a qualitative point of view.

Skutterudites are an important class of thermoelectric p- and n-type materials and they have already achieved fair efficiencies for the conversion of heat to electricity. Nevertheless researchers try to further enhance the figure of merit, ZT, by various ways. In this work we compare the microstructure and mechanical properties of an industrial p-type DDyFe3CoSb12 skutterudite powder processed by several routes containing various combinations of ball milling, hot pressing, cold pressing and high pressure torsion. Details of the resulting microstructure are studied by means of analytical electron microscopy as well as by means of local mechanical testing.

Diamond-like composite coatings were deposited by PACVD with an interface magnetron sputtered metallic layer prepared by d.c. unbalanced magnetron sputtering onto HSS substrates. The focus of the present work was on the study of the humidity effect on the tribological properties, hardness and impact resistance of the deposited coatings. The coatings were tested under both dry and humid conditions using several testing methods, like the pin-on-disc test equipped with linear reciprocating movement, impact test and depth sensing indentation test. It was found that the humidity may substantially influence not only the results of tribological tests, but surprisingly, also the results of the dynamic wear and hardness tests. By increasing the relative humidity, the value of dynamic impact resistance increased at an equivalent stress of 1.6 GPa more than three times. On the other hand, the wear rate of the coated part increased by more than four orders of magnitude. The results of the indentation test were influenced by humidity mainly at nanometre scales. The hardness measured at dry conditions was higher by 25% than the values obtained by the measurements under humid conditions.

The sample of hydrogenated DLC on c-Si prepared by PECVD technique was investigated by ellipsometry in the NIR-UV range (0.6-6.5 eV), synchrotron ellipsometry in the UV-XUV range (4-20 eV) and reflectometry in NIR-UV range (1.24-6.5 eV). Various dispersion models based on the parametrization of density of states (PDOS) were investigated concerning their application in wide spectral range extending to XUV. In conclusion, the further developed PDOS model demonstrated its applicability to correct the calculation of the dielectric response of hydrogenated DLC material in the wide spectral range. Naturally, it can be used for any other disordered materials and it will, together with the optical measurements extended to XUV, bring important information about their band structure.

The functionalization of multi-walled CNTs in O2/Ar and H2O/Ar low pressure capacitive discharges was studied by XPS and FT-IR. The pristine and functionalized CNTs were used as fillers in polyurethane paints. Successful plasma functionalization was confirmed by changes in atomic composition and chemical shift of XPS atomic signals. The functionalization was indicated also by the shift of IR absorption peaks corresponding to the motion of carbon skeleton, especially the peak at about 1560cm-1. The presence of carbonyl was confirmed by IR absorption peak at 1723cm-1 only for O2/Ar plasma. The plasma functionalized CNTs increased significantly the universal and plastic hardness of the CNTs reinforced polyurethane as compared to the composites with pristine CNTs.

Complete optical characterization of diamond-like carbon (DLC) films non-uniform in thickness is performed using spectroscopic imaging reflectometry (SIR). It is shown that by using this technique it is possible to determine the area distribution (area map) of the local thickness of these films with arbitrary shape of this thickness non-uniformity. Furthermore, it is shown that in principle it is possible to determine the distributions of the refractive index and extinction coefficient of these films simultaneously with the thickness distribution, if a suitable dispersion model of these optical constants is chosen. In this paper the dispersion model of the optical constants of the DLC films based on parameterization of density of electronic states (DOS) is used. The values of the material parameters of this dispersion model are determined too. It is shown that the DLC films studied do not exhibit the area non-uniformity in material parameters and optical constants. The method presented can be used to characterize the non-uniform films consisting of other materials.

Recently, the model of DLC dielectric response based on parametrization of density of states (PDOS) was published and successfully employed for the study of structural changes of DLC films. However, certain simplifications were made in this model which influence on determination of optical constants and PI-to-SIGMA ration of DLC films will be discussed in this contribution.

Optical characterization of diamond-like carbon (DLC) films non-uniform in thickness is performed using spectroscopic phase-modulated ellipsometry. This characterization is based on new formulas for the associated ellipsometric parameters of thin films exhibiting a wedge-shaped thickness non-uniformity. These formulas express the associated ellipsometric parameters by means of the density of distribution of local film thickness. The spectral dependences of the optical constants of these non-uniform DLC films are expressed using the dispersion model based on parametrization of density of electronic states. It is shown that this model of the thickness non-uniformity provides a relatively good agreement between the experimental and theoretical data, indicating that the results of the optical characterization of the non-uniform DLC films are close to the correct results. Moreover, it is shown that the model of uniform thin films is unsuitable for the optical characterization of the non-uniform DLC films studied.

Zirconia stabilized with various concentrations of rare earth oxides of Yb, Sm and Y with different effective ionic radii ratio between the dopant and host cations was studied. In particular, structure, phase composition, compositional range for existence of cubic solid solutions and their phase transformations, stabilization degree of high-temperature phases and the crystal chemistry and type of solid solutions were investigated. These findings were related to the measured material characteristics, namely the electrical conductivity, microhardness and effective elastic modulus, to elucidate various effects important for practical applications, such as an increase of electrical conductivity due to the pyrochlore phase occurrence or an increase of microhardness arising from the effect of dynamic strain ageing.

Two formulae expressing the reflectance of non-uniform thin films are presented. The first of them corresponds to the arbitrary shapes of this non-uniformity and illuminated light spot under the assumption that this non-uniformity is sufficiently slight. The second formula corresponds to the wedge-shaped non-uniformity of arbitrary magnitude within the circular light spot. It is shown that both the formulae are suitable for the successful optical characterization of non-uniform diamond-like carbon (DLC) thin films in contrast to the usually used reflectance formula for the uniform thin films. Within the optical characterization the values of the standard deviation of non-uniformity is determined together with the correct values of the mean thickness and material parameters corresponding to the dispersion model based on the parametrization of the density of electronic states. On the basis of the material parameters determined the correct spectral dependences of the optical constants of the DLC films studied are calculated.