This study investigates Cr-Mn-Mo-Si-Y-(N) high-entropy alloy and high-entropy nitride coatings, combining strong and weak nitride-forming elements with large atomic radii differences. The coatings are deposited using reactive DC magnetron sputtering in an Ar/N2 atmosphere. The research examines the effects of varying N2 flow rates, substrate temperatures, and bias. The coatings are stabilized by nitrogen vacancies as N content saturated under 45 at.%. It is observed that bias does not influence chemical composition or structure. Nanostructure analysis reveals that coatings are composed of Cr-Mo-rich with nanocrystallites and amorphous Si-Mn-rich nanolayers. Crystallization occurs in coatings that contain at least 40 at.%. of Nand are deposited at 580 degrees C. The mechanical properties improve with nitrogen incorporation and 580 degrees C substrate temperature, achieving peak hardness and reduced modulus of 15.5 and 195.1 GPa, respectively. Elastic HIT/Er and plastic H3IT/Er2 deformation parameters reach values up to 0.09 and 0.12 GPa, respectively. The results suggest that the high content of Mn, which is a weak nitride former, and the lattice distortion caused by Si and Y, hindered longrange ordering. The study highlights that nitrogen content strongly governs the properties of high-entropy nitride coatings, offering first insights into this novel material system.

Organosilicon plasma-polymer coatings based on hexamethyldisiloxane (HMDSO) are versatile materials with a wide range of applications. However, the degradation of their mechanical properties has not been extensively studied, despite growing application-oriented interest. This study focuses on evaluating the aging of mechanical properties in plasma-polymerized hexamethyldisiloxane (ppHMDSO) coatings, driven by structural changes over time. We investigate the chemical interactions of nitrogen-doped organosilicon thin films with ambient atmosphere under controlled laboratory conditions. These films were prepared via plasma-enhanced chemical vapor deposition (PECVD) using a capacitively coupled radio-frequency (RF) glow discharge in a mixture of HMDSO and N2. To assess the time-dependent mechanical properties of these rapidly degrading plasma polymers, nanoindentation and microindentation techniques were employed. Quasi-static partial unloading (QSpul) experiments and differential hardness (HD) measurements were also conducted to analyze how mechanical properties evolve with structural changes during aging. Trends in the mechanical properties were correlated with FTIR and XPS analyses to provide insights into the underlying aging mechanisms of nitrogen-doped HMDSO thin films.

Correct data processing and uncertainty assessment is crucial for metrology. One of the most common methods used is function fitting using non-linear least squares. This numerical method has been implemented in probably all data processing software and is quick and easy to use. Unfortunately, it has its limitations – notably it works only for very simple models of the uncertainties present in the system. Uncertainties in the dependent variable cannot be taken into account, and neither do correlations. Errors-in-variables models minimize a generalized distance of the points from the fitted function. The metric used to compute the distance is given by the inverse of the covariance matrix. Thus, the estimates of the uncertainties entering the computation may affect the resulting estimates of the fitted parameters. In this contribution we illustrate the use of an iterative EIV algorithm on an example from nanoindentation, especially the sensitivity of the results to input data including uncertainties.

TiZrN coatings were prepared using three bias voltages of -50 V, -100 V and -175 V via a combinatorial approach, which led to the coatings with different Ti/(Ti+Zr) values. The deposition rate of TiN and ZrN remained practically constant with increasing the bias voltage. The TiZrN coatings, however, exhibited a drop of similar to 15% in their deposition rates with increasing the bias voltage. The microstructure of TiN and ZrN did not change with the bias voltage applied, unlike TiZrN, which underwent microstructural changes with increasing bias voltage. For all binary and ternary nitrides, the lattice parameter increased and crystallite size decreased with increasing the bias voltage. All TiN, ZrN and TiZrN coatings showed enhanced compressive stress with increasing the bias voltage. ZrN hardness peaked at the bias voltage of -100 V, in contrast to that of TiN, which exhibited a constant increase with the bias voltage and peaked at -175 V. In ternary nitrides, bias voltage significantly influenced the hardness values, whereas in the case of Ti/(Ti+Zr), the effect was minimal, especially at the higher bias voltages. For all binary and ternary coatings, H/Eef and H3/Eef2 increased with the bias voltage, indicating an enhanced wear resistance and resilience with increasing bias voltage.

The crystal structures of the "hectoborides" NdB65 and ThB60 have been elucidated from single crystal X-ray structure determination supported by TEM-SAED analyses. Both compounds crystallize in a face-centred cubic lattice with space group Fm (3) over barc (No. 226) (a(NdB65) = 2.35385(4) nm, R-F = 0.0491; a(ThB60) = 2.35170(5) nm, R-F = 0.0489) isotypic with the aristo-type of hectoborides, namely YB66. With respect to the structure type of YB66 in its original version by Richards and Kaspar [2], we observe for both compounds, NdB65 and ThB60, a split position (total occupancies 0.5) for the metal atoms in site 48f as well as a second metal atom position in site 8a at a reduced occupancy; furthermore, we only arrive at seven B-sites 192j and 5 B-sites 96i, but did not find a B-atom (B13) in site 64g (x = 0.23, x, x). In contrast to the earlier structure determination of ThB66(O) [11] our WDX analysis did not present any hints for oxygen contamination, therefore site 8a (1/4,1/4,1/4) hosts a Th atom at low occupancy of 0.12(1) Th instead. Similarly, the 8a site is also partially occupied by 0.04(1) Nd in NdB65. Whereas the present investigation removes all doubts on the formation of NdB65 (YB66-type), our analysis did not reveal the formation of isotypic "PrB66". On the basis of our SEM data, revised phase relations for the three systems Nd-B, Pr-B and Th-B have been designed for the boron-rich part (>85 at.% B). Whereas at room temperature hardness of ThB60 (23.8 GPa) and for NdB65 (24.3 GPa) fit well among hardness data for the corresponding rare earths hectoborides, the by-product material ThB99 (beta B-type) with 42 GPa is a superhard material.

HPT (high pressure torsion)-processed samples of p-type skutterudite DD0.7Fe3CoSb12 were systematically investigated for clarifying the mechanisms behind the enhancements of mechanical properties and particularly of the thermoelectric figure of merit ZT. For the first time we combined experiments (differential scanning calorimetry, X-ray diffractometry, energy dispersive spectroscopy, and scanning electron microscopy) with calculations by density functional theory (DFT). The results demonstrated that the individual thermal stabilities of lattice defects from HPT-processing with special respect to their densities and arrays are responsible for the properties observed. The mechanical properties are mainly governed by dislocations and grain boundaries, while the thermoelectric figure of merit ZT is affected by the generation and annihilation of vacancy type defects: These allow for the formation of low-angle grain boundaries out of the HPT induced dislocations with increasing misorientation between the grains as a function of deformation and annealing temperature. In contrast to simply entangled dislocation cell walls, these low/high angle grain boundaries account for a minimum of the product of resistivity and thermal conductivity, and thus of a maximum of ZT. DFT calculations not only provided formation energies of vacancies for the three atom sites in NdFe4Sb12 and NdCo4Sb12, but also insight on the stabilities of these compounds. The Nd vacancy formation in NdCo4Sb12 is the least energy-demanding, which makes the structure more stable than e.g. the Nd vacancy formation in NdFe4Sb12, where decreasing electron deficit competes with increasing structure distortion.

Reactive sputter deposition of TiN, ZrN, and TiZrN coatings at different nitrogen partial pressures was performed under industrial conditions using a combinatorial approach. For all coatings, the nitrogen content rose with increasing nitrogen partial pressure and then leveled off above a given pressure. The ZrN coatings exhibited a columnar structure irrespective of the nitrogen pressure used. In contrast, the microstructure of TiN and TiZrN varied depending on the nitrogen partial pressure. A different behavior of the crystallite size as a function of the nitrogen partial pressure was observed for TiN and ZrN. A strong dependence was noticed for TiN. This contrasted with the behavior of ZrN which had much smaller crystallites. Smaller crystallites were also observed in the TiZrN coatings and the influence of the nitrogen partial pressure and the Ti/(Ti + Zr) ratio on these coatings was weak. The coloration of the coatings was notably influenced by nitrogen partial pressure. The level of red for the TiN and TiZrN coatings and the yellow hue for the ZrN coatings significantly increased with nitrogen partial pressure. The hardness of all TiZrN coatings peaked at intermediate nitrogen partial pressures, which indicates that nitrogen partial pressure enables the optimization of mechanical properties. The highest measured hardness (31 GPa) was obtained at a Ti/(Ti + Zr) ratio of 0.50 although similar values were obtained irrespective of the metallic elements. This study demonstrates the potential to enhance the mechanical properties of TiN by incorporating Zr provided the correct nitrogen partial pressure is selected.

This paper is focused on plasma-enhanced chemical vapor deposition (PECVD) of novel carbon-based thin films. Unique thin films were deposited from a mixture of methane, hydrogen, and a precursor containing fluorine and copper: (hfac)copperVTMS (hfac = hexafluoroacetylacetonato and VTMS = vinyltrimethylsilane). Using the (hfac)copperVTMS precursor in PECVD deposition results in the advantageous chemical composition of carbon-based thin films while maintaining sufficient mechanical properties. Furthermore, with optimized plasma parameters, the films deposited on the substrate exhibit a nanocomposite structure. This nanostructured surface can increase the surface area, which is beneficial for various applications, including antibacterial and antiviral properties. The radiofrequency glow discharge at low pressure (≈70Pa) and power P=25W and P=250W was used for deposition. Deposited thin films were analyzed using X-ray photoelectron spectroscopy, water contact angle measurement, atomic force microscopy, and nanoindentation techniques. Despite the doping of carbon-based thin films with soft copper, the prepared films exhibited sufficient mechanical properties, which are crucial for the future implementation of this deposition process.

The paper reports on the phase stability of the (FeCoNi) 0.75 Cr 0.25-x Cu x HEA system with equimolar ratio of Fe, Co and Ni by differential scanning calorimetry (DSC) and measurements of physicochemical properties: density, electrical resistivity, Seebeck coefficient, thermal conductivity, and magnetic behaviour in a broad temperature region as well as hardness and elastic modulus at room temperature as a function of the gradual substitution of chromium by copper in a series of (FeCoNi) 0.75 Cr 0.25-x Cu x alloys with different mole fraction of Cu (x = 0, 0.05, 0.1, 0.15 and 0.2). DSC measurements showed that all alloys are thermally stable. Increasing content of Cu was found (i) to increase the formation of a fcc Cu-rich phase, (ii) to strengthen ferromagnetic interactions, resulting in rising ordered magnetic moments, as well as in growing ferromagnetic transition temperatures, and (iii) to distinctly change physical properties like electrical resistivity, thermal expansion, and mechanical properties. Experimental data regarding the phase stability are supported by CALPHAD calculations.

To build thermoelectric generators, leg materials with a high figure of merit, ZT, are essential. Skutterudites are promising candidates because besides being environmentally friendly, the starting material is available and cheap and they can be used in a wide temperature range. To enhance ZT, severe plastic deformation via high-pressure torsion, HPT, was successfully applied on ball-milled and hot-pressed skutterudites as well as to directly densify skutterudite powder. Severe plastic deformation introduces many defects, mainly dislocations, into the sample and in parallel the crystallite size is significantly reduced. During measurement-induced heating these defects anneal partially out, and the grains grow. It was observed that while heating HPT processed material from room temperature to about 850 K, changes of the temperature-dependent physical properties, most of all the electrical resistivity, the density, and the thermal expansion occur more or less simultaneously around 600 K. For the first time we have combined in situ TEM observations as well as in situ measurements of the elastic modulus and hardness in order to get a deeper insight into the microstructural behavior of a p-type skutterudite, DD0.7Fe3CoSb12 (DD = didymium) during increasing temperature from 300 K to 823 K. HPT-DD0.7Fe3CoSb12 is a high quality thermoelectric material with 1.2 < ZT < 1.4 at 750 K (hot-pressed reference sample: ZT similar to 1.2 at 810 K).

The Hf-Mn system is of a long-time interest due to the intermetallic Laves phase HfMn2, a hydrogen storage material. Although this system has been experimentally investigated by several authors and critical reviews and thermodynamic modelling have been performed, there is still a lack of reliable information, particularly as the phase "HfMn" (sometimes labelled as "Hf3Mn2" or "Hf2Mn") is suspected to be oxygen stabilized. This work includes a thorough investigation of the Hf-Mn phase equilibria employing diffusion zones, thermal analysis, powder and single crystal X-ray analyses, analytical electron microscopy as well as physical property studies of the Laves phase (magnetic susceptibility, specific heat, electrical resistivity and mechanical properties). The phase near "HfMn" was shown (TEM, WDX electron microprobe data, X-ray single crystal analysis) to be an oxygen stabilized phase with the formula Hf3+xMn3_xO1_y (defect eta-W3Fe3C type). Properties such as magnetic susceptibility/magnetization; 2-300 K, specific heat (2-1100 K), electrical resistivity (2-300 K) classify HfMn2 as a metallic spin-fluctuation system with itinerant paramagnetism, originating from 3d states at Mn-sites and local moment paramagnetism of antisite Mn-atoms at Hf-sites. Mechanical properties (elastic moduli from density functional theory (DFT) and nanoindentation as well as hardness) group the Laves phase among rather hard and brittle intermetallics. DFT modeling revealed that Hf3+xMn3_x is thermodynamically unstable, but significant gains in enthalpy of formation arise from the inclusion of oxygen atoms, stabilizing the eta phase. All phase diagram and DFT data together with the former literature information were used for the thermodynamic CALPHAD-type modelling of the Hf-Mn system.

In this study, an optical investigation in a wide spectral range of polymer-like (SiOxCyHz) thin films deposited by plasma-enhanced chemical vapor deposition (PECVD) is presented. The primary focus is on assessing the homogeneity of the grown films. Within the PECVD, it is possible to alter the properties of the deposited material by continually adjusting deposition process parameters and hence allow for the growth of inhomogeneous layers. However, as shown in this study, the growth of homogeneous layers could be similarly challenging. This challenge is especially pronounced at the beginning of the deposition process, where it is necessary to consider the influence of the substrate among other factors, as even slight variations in the deposition conditions can lead to the formation of inhomogeneous layers. Several series of polymer-like thin films were deposited onto silicon substrates with the goal of producing homogeneous layers, i.e. all deposition parameters were held constant. These samples were optically characterized with a special interest in homogeneity, especially at the beginning of the growth. It was found that initial inhomogeneous growth is always present. The thickness of the initial inhomogeneous part was found to be surprisingly large.

The main aim of the present study was to develop hard a-C:H:SiO x coatings prepared from the unique gaseous mixture of trimethylsilyl acetate (TMSAc) with methane using plasma of RF capacitively coupled glow discharge. Studied coatings were prepared using different methane ratios in TMSAc/CH 4 gaseous mixtures ranging from 7.1 % to 85.7 %. Simultaneously, the influence of the power supplied to the discharge (25 -100 W) on the properties of resulting coatings was investigated. The presented research work discusses in detail the evolution of chemical composition, mechanical characteristics, and optical properties of resulting coatings depending on variable CH 4 ratio and discharge power. Within this study, various materials with the smooth surface structure were achieved. Applying low CH 4 ratio and 25 W power led to the formation of soft SiO x C y H z coatings with high content of Si -O and -CH 3 groups exhibiting hardness of approx. 0.95 GPa. Gradually increasing the CH 4 ratio and discharge power up to the specified limit values (85 % and 100 W, respectively) induced structural changes, resulting in a-C:H:SiO x coatings with a remarkable hardness of 11 GPa and excellent fracture resistance. These attributes are of utmost importance in numerous industrial applications, including anticorrosive coatings, low-friction wear-resistant coatings to prolong the lifetime of car engines, biocompatible coatings, components for plastic molds, as well as parts for optical disc molds and textile machinery.

This article presents theoretical and experimental findings on the stability of orthorhombic (Mo1-,,Nb,,)2BC phase in magnetron sputtered coatings, where molybdenum is gradually replaced by niobium. Magnetron co -sputtering of Mo2BC and Nb2BC targets was used to best preserve the metal/non-metal ratio of 1/1. The theoretical calculations were based on replacing Mo atoms in orthorhombic Mo2BC cell, thus creating a (Mo1-,,Nb,,)2BC solid solution. It is predicted to be stable up to 37.5% of Mo atoms replaced by Nb, at which point also the elastic modulus and the shear modulus are the highest. Simultaneously, the enthalpy of formation of this material suggests that it should be more stable than, e.g. the commonly used and studied TiAlN. Experiments have confirmed that orthorhombic (Mo1-,,Nb,,)2BC does not form at high Nb contents, and fcc NbC-like structure was observed instead. All coatings were shown to be columnar with grains in the nanometre range with amorphous regions between the columns. This led to reduced stability of the orthorhombic Mo2BC- like phase compared to the theoretical calculations. At the limit of the stability of the orthorhombic cell, the hardness of the coating was enhanced by 25% and the elastic modulus by 60%. Ab initio calculations indicate that lattice strain is responsible for the mechanical properties' enhancement.

ZrN-Cu coatings containing two different amounts of Cu (~11 at.% and ~25 at.%) were deposited using an industrial physical vapor deposition (PVD) system. The as-deposited coatings exhibited 100% bactericidal efficiency against Escherichia coli CCM 3988 for an exposure time of 40 min. Subsequently, the samples were attached onto our faculty’s door handles for six months to study the coatings’ long-term effectiveness and durability under actual operational conditions. The samples were periodically evaluated and it was observed that the coatings with 25 at.% Cu performed better than the ones with 11 at.% Cu. For example, following 15 days of being touched, the bactericidal effectiveness of the sample containing 25 at.% Cu dropped to 65% while it fell to 42% for the sample containing 11 at.%. After 6 months, however, both samples showed bactericidal efficiency of ~16–20%. The bactericidal efficiency of the samples touched for 6 months was successfully restored by polishing them. Furthermore, a group of samples was kept untouched and was also evaluated. The untouched samples with Cu content of ~25 at.% did not show any drop in their bactericidal properties after 6 months. ZrN-Cu coatings were concluded to be promising materials for self-sanitizing application on high-touch surfaces.

In this study, the chemical and physical properties of sol–gel coatings were analyzed after curing with various atmospheric plasma sources.

Lucrarea de fata se refera la studiul filmelor subtiri de carbon-metale (C-Me) depuse prin metoda Arcului Thermionic in vid (TVA) în configurația cu un tun eletronic, pe suport de sticla si siliciu cristalin. Filmele au fost investigate pentru a determina structurile formate, in scopul de a contura proprietatile si gama de aplicatii posibile. Morfologia de suprafata si udabilitatea au fost analizate prin microscipia de transmisie de electroni (TEM), microscopia de scanare prin electroni (SEM) si prin metoda SEE SYSTEM. Rezultatele furnizate prin microscopia de electroni au aratat modalitatea in care structurile de Ag, Mg and Si au interactionat cu carbonul si influenta pe care aceste materiale le au asupra formarii structurale si a distributiei particulelor. Analiza SEM corelata cu rezultatele (Energy Dispersive X-ray) EDX results conferă un studiu comparativ pentru a intelege structura complexa nanocristalina, in functie de elementul introdus (Ag, Si, Mg) in matricea de carbon pe substratul respectiv (Si, SiO2).

The optical characterization of non-absorbing, homogeneous, isotropic polymer-like thin films with correlated, differently rough boundaries is essential in optimizing their performance in various applications. A central aim of this study is to derive the general formulae necessary for the characterization of such films. The applicability of this theory is illustrated through the characterization of a polymer-like thin film deposited by plasma-enhanced chemical vapor deposition onto a silicon substrate with a randomly rough surface, focusing on the analysis of its rough boundaries over a wide range of spatial frequencies. The method is based on processing experimental data obtained using variable-angle spectroscopic ellipsometry and spectroscopic reflectometry. The transition layer is considered at the lower boundary of the polymer-like thin film. The spectral dependencies of the optical constants of the polymer-like thin film and the transition layer are determined using the Campi–Coriasso dispersion model. The reflectance data are processed using a combination of Rayleigh–Rice theory and scalar diffraction theory in the near-infrared and visible spectral ranges, while scalar diffraction theory is used for the processing of reflectance data within the ultraviolet range. Rayleigh–Rice theory alone is sufficient for the processing of the ellipsometric data across the entire spectral range. We accurately determine the thicknesses of the polymer-like thin film and the transition layer, as well as the roughness parameters of both boundaries, with the root mean square (rms) values cross-validated using atomic force microscopy. Notably, the rms values derived from optical measurements and atomic force microscopy show excellent agreement. These findings confirm the reliability of the optical method for the detailed characterization of thin films with differently rough boundaries, supporting the applicability of the proposed method in high-precision film analysis.

We use reactive DC magnetron sputtering to showcase synthesis strategies for multicomponent carbides with the NaCl-type fcc structure and illustrate how deposition conditions allow controlling the formation of metallic and ceramic single phases in the Cr-Hf-Mo-Ta-W system. The synthesis is performed in argon flow and different acetylene flows from 0 to 12 sccm, at ambient and elevated temperatures (700 degrees C), respectively, hindering/promoting the adatom diffusion. Structural and microstructural investigations reveal the formation of the bcc metallic phase ( a = 3.188 - 3.209 & Aring;) in films deposited without acetylene flow, also supported by ab initio density function theory (DFT) analysis of lattice parameters as a function of the C content. Experimentally, a bcc-to-fcc phase transition is observed through the formation of an amorphous coating. Contrarily, samples deposited in higher acetylene flow show an fcc multielement carbide phase ( a = 4.33 - 4.49 & Aring;). The crystalline films reveal columnar morphology, while the amorphous ones are very dense. We report promising mechanical properties, with hardness up to 25 +/- 1 GPa. The indentation moduli reach up to 319 +/- 6 GPa and show trends consistent with DFT predictions. Our study paves the path towards the preparation of Cr-Hf-Mo-Ta-W multicomponent carbides by magnetron sputtering, showing promising microstructure as well as mechanical properties.

A number of industrial applications today require thermally sprayed coatings that exhibit good adhesion, high temperature and chemical resistance, and can withstand particle impacts or dynamic interactions with components. A common example of a high-velocity oxygen fuel (HVOF) sprayed coating with such the aforementioned properties is Cr3C2-25%NiCr. The objective of this study is to examine the impact of varying thicknesses and surface roughness on the impact lifetime and impact wear of Cr3C2-25%NiCr coatings. A series of Cr3C2-25% NiCr coatings were subject to analysis using a dynamic impact tester with impact loads of 200 N, 400 N, and 600 N. The results indicated that there exists an optimal coating thickness with the highest impact lifetime. The results were discussed using microstructural analysis of the impact coatings and finite element simulation. The maximum impact lifetime was achieved with the optimal combination of sample material properties, substrate mechanical properties, coating thickness, and residual stress. Furthermore, it was demonstrated that surface does not influence the impact lifetime of the coating, but does affect the accuracy of its determination.