Refractory high entropy TiTaZrHfW-N/Si3-N4 nano-layered alloy thin films are investigated to study the effect of nano-layered architecture and silicon (Si) mean content on their structural, mechanical, thermal properties and oxidation behavior. The films are deposited using direct current (DC) magnetron sputtering of separate Si and TiTaZrHfW targets. The Si mean content is controlled by tailoring the power discharge applied to the Si target. The deposition process led to a nano-layered architecture where Si3N4 (amorphous) and TiTaZrHfW-N (nanocrystalized NaCl FCC type structure) are alternated. By increasing the thickness of Si3N4 nano-layers, the Si mean content increases. All coatings are found to have good thermal stability after annealing under vacuum at 900 degrees C. Increasing Si mean content reduces the film's hardness; however, the annealing treatment at 900 degrees C improves it. A super-hardness of 41 GPa is found for the post-annealed Si-free film. Si3N4 nano-layers enhance the oxidation resistance at elevated temperatures of 600, 700, and 800 degrees C. This oxidation resistance is further enhanced by increasing the nano-layer's period and also by increasing the density of the films.

This work uses the direct current magnetron sputtering (DCMS) of equi-atomic (AlTiZrHfTa) and Si targets in dynamic sweep mode to deposit nano-layered (AlTiZrHfTa)Nx/SiNx refractory high-entropy coatings (RHECs). Transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) are used to investigate the effect of Si addition on the oxidation behavior of the nano-layered coatings. The Si-free nitride coating exhibits FCC structure and columnar morphology, while the Si-doped nitride coatings present a FCC (AlTiZrHfTa)N/amorphous-SiNx nano-layered architecture. The hardness decreases from 24.3 ± 1.0 GPa to 17.5 ± 1.0 GPa because of the nano-layered architecture, whilst Young’s modulus reduces from 188.0 ± 1.0 GPa to roughly 162.4 ± 1.0 GPa. By increasing the thickness of the SiNx nano-layer, kp values decrease significantly from 3.36 × 10−8 g2 cm−4 h−1 to 6.06 × 10−9 g2 cm−4 h−1. The activation energy increases from 90.8 kJ·mol−1 for (AlTiZrHfTa)Nx nitride coating to 126.52 kJ·mol−1 for the (AlTiZrHfTa)Nx/SiNx nano-layered coating. The formation of a FCC (AlTiZrHfTa)-Nx/a-SiNx nano-layered architecture results in the improvement of the resistance to oxidation at high temperature.

Coatings play a key role in modern industry, enhancing the performance of materials. The diversity of their applications and constant progress make them a central area of research and development in materials science and engineering. In this manuscript, we examined some recent works of high-entropy coatings deposited by magnetron sputtering. The first section provides details on the magnetron sputtering technique and deposition mechanism. The change of the parameter influences the microstructure and then the properties of the films. High Power Impulse Magnetron Sputtering is sued to increase the compactness of the film. In the second, a spotlight on High-Entropy Films (HEFs) as an emergent-class material is presented and how their oxidation resistance is improved. Particular attention is being paid to studying the effect of some alloying elements, such as nitrogen and silicon, on oxidation resistance improvement. The last section presents potential applications of these coatings, especially the cutting tools, the diffusion barrier, and other industrial uses.

(AlTiZrHfTa)1-xNx refractory high entropy films (RHEFs) were deposited by direct current magnetron sputtering in various nitrogen ratios (RN2 = N2/(Ar+N2)) on flat glass, silicon and sapphire substrates. The nitrogen-free film is amorphous while the nitrides are single-phased solid solutions with Face-Centered Cubic (FCC) structures. The hardness increases from 6.4 GPa for the nitrogen-free film to 25.3 GPa for the film obtained at RN2 = 20%. A preferred orientation from (111) to (200) occurs when RN2 increases from 5% to 50%. H/E and H3/H2 reports show high values for the film deposited at RN2 = 20% compared to that at 10%. However, this latter has the best compromise in terms of mechanical properties related to a lower residual stress value. The nitrides films obtained with RN2 >= 5%, are thermally stable at 800 degrees C for 3 h under vacuum. Compared to the metallic film they show an improved oxidation resistance. In fact, the Kp constant of the nitride (RN2=20%) is lower (1.22 10-7 g2 cm-4 h-1) than that of the nitrogen-free film (1.77 10-6 g2 cm-4 h-1). The corresponding activation energies (Ea) are respectively calculated at 94.8 KJ. mol-1 and 45.5 KJ.mol- 1. After oxidation process, TEM analysis reveal the formation of homogeneous mixed oxide.

In the last decades, refractory high entropy thin films have attracted more attention due to their superior properties at high temperatures. Besides the thermal stability, these new materials present good mechanical properties at high temperatures, which is interesting compared to conventional alloys. TiTaZrHfW(-N) films are deposited by reactive magnetron sputtering in various argon/nitrogen atmospheres. Optical emission spectroscopy is performed to analyze the target poisoning conditions and optimize the deposition parameters. The nitrogen flow rate ratio RN = phi N2/(phi N2 + phi Ar) is varied from 0 to 29 %. XRD analyses show a phase transition from amorphous to B1(NaCl) single phased films once the nitrogen is added. For all nitrides, an out-of-plane {111} preferential orientation is observed, except for RN = 9 %, for which it changes to {200}. The morphology of the films changes from compact to columnar when the nitrogen ratio exceeds 5 %. The hardness and Young's modulus are also studied and present evolution with maximum values, 29 GPa and 257 GPa for RN = 9 % respectively. All nitrides show good thermal stability under vacuum at 800 degrees C for 3 h, compared to nitrogen-free metallic film, for which phase transition occurs. Nitrides show improved oxidation resistance compared to that of metallic film.

This work introduces a new way to create 3D printed strain gauges by Direct Paste Deposition. This process is based on various steps of deposition of inorganic materials onto metallic substrates. These materials are based on the alkali activation principle, allowing to reach high temperature application ranges without high thermal treatment of solidification. Two materials are used to build a stacking of insulative and conductive layers to obtain an anisotropic conductive pattern. The use of such materials makes it compatible with tools operating at high temperature environments (over 400 degree Celsius). Rheological analysis has shown the compatibility of the extruded paste with extrusion processes. To ensure critical size control of the conductive pattern, the paste rheology and the printing parameters have been optimized. Electrical resistivity of the pattern have been characterized. The process of direct paste deposition makes the printing of strain gauges compatible with additively manufactured products and opens the opportunity to integrate electronics onto and/or into complex objects.

This work aims at understanding the nucleation and growth of alumina films grown on Ti(C,N)-based layers using an industrial-scale CVD system. Firstly, Al2O3 layer was deposited on Ti(C,N)-based layers without any nucleation treatment, pure α-Al2O3 is obtained, whereas no orientation relationship at the Ti(C,N)/α-Al2O3 layers interface can be observed. Secondly, Al2O3 layer was deposited on the bonding layer consisting of rutile TiO2, which is obtained by oxidizing the uppermost part of Ti(C,N)-based layers. Herein, α-Al2O3 single-phased layer is obtained, and the epitaxial growth of α-Al2O3 on rutile is observed. The orientation relationships can be found as:(1¯20)α-Al2O3//(101¯)rutile, (003)α-Al2O3//(010)rutile and [210]α-Al2O3//[101]rutile. Finally, Al2O3 layer was deposited on the bonding layer, produced from a TiCl4-H2-N2-CH4-CO-AlCl3 gas mixture. Regarding this intermediate layer, despite additions of CO and AlCl3, no evidence for oxide phases, e.g. TiO2 and Al2O3 can be found, while Ti(C,N) needle-shaped grains develop. In this case, κ-Al2O3 is epitaxially grown on Ti(C,N), with the orientation relationships found as:.(01¯3)κ-Al2O3//(2¯20)Ti(C,N), (100)κ-Al2O3//(1¯1¯1)Ti(C,N) and [031]κ-Al2O3//[112]Ti(C,N). Since processing parameters for the alumina depositions were always the same, it is revealed that the nucleation of α-Al2O3 and κ-Al2O3 can be accurately controlled with deposition of specific bonding layers.

The last decade has seen emerged numeric transition in industry, bringing new building blocks: Internet of Things (IoT) and additive manufacturing. A whole big new challenge was born based on sensors integration with the capability to bring intelligence into objects leveraging on additive manufacturing topological optimization, and thus operating in harsh environment thanks to efficient packaging. This work presents a new way to create 3D printed electronic patterns, based on Paste Extrusion Modeling (also called Direct Ink Writing) to extrude a superposition of insulator and conductive inorganic materials. Their raw compositions were characterized through EDS and XRD and compared to their datasheets. The obtained patterns show great electrical behavior under mechanical oscillation, opening possibilities for strain measurement.

There is a growing interest in the design of high entropy alloys due to their remarkable properties and applications in various fields such as aerospace, medical and automotive. AlTiTaZrHf(-N) high entropy metalsublattice nitrides were deposited in various argon-nitrogen gas mixtures on glass and silicon substrates. X-ray diffraction analyses reveal a transition from amorphous to an FCC single phase by increasing the nitrogen content. The films have compact or columnar morphology depending on the nitrogen flow rate. Energy dispersive spectroscopy analysis shows a decreasing of the matals content as the nitrogen flow rates ratio R-N2 = N-2/Ar + N-2 increases. XPS surface analysis reveal the formation of nitrides when the nitrogen is introduced. Evolution of hardness and Young's modulus are discussed and the maximum values are obtained for a flow rates ratio R-N2 of 10% at 27.67 GPa and 205.56 GPa respectively. The same film reveals good tribological properties compared to other films. This work conclusively demonstrates that high entropy metal-sublattice nitrides can be generated in an efficient way with tunable properties.

The data presented in this article are related to the published research of “Effect of nitrogen content on structural and mechanical properties of AlTiZrTaHf(-N) high entropy films deposited by reactive magnetron sputtering”. This database contains X-ray photoelectron spectroscopy (XPS) measurements, performed in order to determine the extents of nitrides formed in AlTiTaZrHf high entropy films. The latter were prepared by DC magnetron sputtering technique in reactive mode by adding the nitrogen to argon gas. The nitrogen flow rate is calculated by RN2 = N2/(N2+Ar). XPS measurements were done one month later. Oxides were detected on the top surface of the samples. 2p, 3d and 4f core level peaks were fitted in order to determine accurately the chemical composition of the nitride films. Al2p, Ti2p, Zr3d, Ta4f, and Hf4f reveal the formation of nitrides of all elements constituting the films. Atomic percentage of each element was calculated revealing an increase of nitrogen loading and decrease of the metallic fractions of the elements as RN2 grows from 5% to 50%. Nitridation behaviour of each element, as a function of the nitrogen flow rate, is investigated and presented.

Using an industrial-scale chemical vapor deposition (CVD) system, a series of Ti(C,N) films were deposited from a TiCl4-CH3CN-H-2-N-2 gas mixture at 850-950 degrees C and 70-700 mbar with N-2/H-2 molar ratio varying from 0.27 to 3.77. Within the investigated temperature range, it is found that the growth rate of Ti(C,N) films is strongly dependent on the total pressure. Such behavior agrees with a diffusional limitation step. The lowest growth rate is measured at the N-2/H-2 molar ratio of 3.77, because of the low reduction rate of TiCl4 in a H-2 deficient atmosphere. No significant influence of processing conditions on the carbon content of Ti(C,N) films could be found, as determined by X-ray diffraction and EPMA. The microstructure and mechanical properties were investigated and chiefly influenced by deposition conditions. In this work, the Ti(C,N) films deposited at 850 degrees C and 70 mbar with N-2/H-2 molar ratio of 0.27 exhibit a mixed texture with laminated facetted grains, the superior hardness reaching 30 GPa and the Young's modulus of 394 +/- 32 GPa were measured. Furthermore, experimental results reveal that residual stresses could be thickness-dependent, due to the evolutionary film microstructure during film growth, and the stress relaxation is particularly attributed to cooling cracks.

The LFPECVD (Low-Frequency Plasma-Enhanced Chemical Vapor Deposition) technique is now used on an industrial scale for the deposition of carbon-based coatings for several applications. This short review recalled the main principles of LFPECVD and provided examples of DLC-based films. The main differences between low-frequency (LF) and radio-frequency (RF) discharges were also recalled here and examples of deposition and characterization of carbon-based films were proposed. The influence of the bias voltage or the temperature of the active electrode on the deposition rate and the structure of a-C: H films obtained in cyclohexane/hydrogen mixtures was first discussed. Next, the properties of carbon-based films doped with silicon were described and, finally, it was shown that multilayer architectures make it possible to reduce the stresses without altering their tribological properties.

Cu4O3 thins films were deposited by the reactive magnetron sputtering process on glass and Si (100) wafers. In order to investigate the thermal stability of the Cu4O3 phase, the films were subjected to vacuum annealing treatment for one hour at various temperatures ranging from 200 degrees C to 500 degrees C. The samples were characterized by using EDS, XRD, SEM and UV-VIS. The phase transformation of Cu4O3 into Cu2O was obtained from 300 degrees C (critical temperature). Increasing annealing temperature leads to compact morphology and the grain shape changing from elongated towards spherical. Due to this annealing the film structure presentes coexistence of a Cu4O3 and Cu2O mixture where O atoms are lost in the Cu-O system. The UV-VIS analysis reveals a gradual increase in the transmittances from 55 to 70% with the increasing annealing temperature, while the band gap shows a maximum value (Eg = 2 eV) at 500 degrees C corresponding to the Cu2O phase.

AlTiTaZr(-N) films are synthetized by direct current magnetron sputtering technique with a combinatorial approach. Coatings are deposited on glass and silicon substrates from four pure metallic targets in argon-nitrogen gas mixtures. Films deposited in the center of substrates holder have columnar morphology with less compact structure compared to that of films obtained in the targets? axes positions. Various compositions are obtained in one step at each level of the argon nitrogen mixture. Without nitrogen, the coatings deposited in the axis of the targets are solid solutions derived from the corresponding metal. Increasing the nitrogen flow rate favors the growth of fcc metal nitrides in the targets? axes whereas the fcc single phased films are detected in the center of substrates holder. The metallic composition is quasi-equiatomic in this case. Hardness and Young?s modulus of these MEA films are in the ranges 12-15 GPa and 141.7-142.9 GPa, respectively, and this film?s structure is thermally stable after annealing at 800 °C for 3 h.

Tungsten carbide doped NiCrBSi coatings have been deposited by Laser Cladding (LC) on steel agricultural knives in order to improve their life time. The influence of the mass fraction as well as the particle size of the tungsten carbide powder on structure, microstructure and mechanical properties was analyzed. The mechanical characteristics were studied from micro-hardness tests, pin-on-disc wear tests and cutting tests of plant material. The coating hardness is stable when carbide powder content in the mixture is between 35 and 60 wt%. Then this hardness increases significantly when the carbide content reaches 70 wt%. The wear coefficient in dry conditions decreases when the carbide powder content is increased from 35 to 40 wt%. Further increase of the carbide powder content in the mixture does not affect the wear coefficient. The coating hardness increases with the particle size of the carbide powder. The cutting test shows that the finest particle size (20-53 mu m) of the carbide powder leads to the lowest values of the cutting-edge wear and the mass loss. This is attributed mainly to the better volume distribution of tungsten carbide particles as well as to the resistance of the matrix due to precipitation of the Ni4W phase.

Ta, Hf, TaCx, HfCx, and TaxHf1-xCy coatings were deposited by reactive pulsed Direct Current (DC) magnetron sputtering of Ta or Hf pure metallic targets in Ar plus CH4 gas mixtures. The properties have been investigated as a function of the carbon content, which is tuned via the CH4 flow rate. The discharge was characterized by means of Optical Emission Spectroscopy and, in our conditions, both Ta-C and Hf-C systems seem to be weakly reactive. The structure of the as-deposited pure tantalum film is metastable tetragonal β-Ta. The fcc-MeCx carbide phases (Me = Ta or Hf) are {111} textured at low carbon concentrations and then lose their preferred orientation for higher carbon concentrations. Transmission Electron Microscopy (TEM) analysis has highlighted the presence of an amorphous phase at higher carbon concentrations. When the carbon content increases, the coating’s morphology is first compact-columnar and becomes glassy because of the nano-sized grains and then returns to an open columnar morphology for the higher carbon concentrations. The hardness and Young’s modulus of TaCx coatings reach 36 and 405 GPa, respectively. For HfCx coatings, these values are 29 and 318 GPa. The MeCx coating residual stresses increase with the addition of carbon (from one-hundredth of 1 MPa to 1.5 GPa approximately). Nevertheless, the columnar morphology at a high carbon content allows the residual stresses to decrease. Concerning TaxHf1-xCy coatings, the structure and the microstructure analyses have revealed the creation of a nanostructured coating, with the formation of an fcc superlattice. The hardness is relatively constant independently of the chemical composition (22 GPa). The residual stress was strongly reduced compared to that of binary carbides coatings, due to the rotation of substrates.

Cu–Zr–Ta ternary thin film metallic glasses (TFMGs) were deposited through the direct current (DC) magnetron sputtering of pure metallic targets in a dynamic mode. The effect of tantalum addition on the microstructure, mechanical properties, and thermal behavior of TFMGs were investigated. Nanoindentation measurements showed that an increase in tantalum content from 0 to 47 at % favored hardness and Young’s modulus, which rose from 5.8 to 11.23 Gpa and from 90 to 136 Gpa, respectively. XRD analysis and differential scanning calorimetry (DSC) measurements highlighted an improvement of thermal stability with the tantalum addition from 377 to 582 °C when the tantalum content increased from 0 to 31 at %.

New AlTiTaZr medium entropy films (MEFs) are elaborated by using direct current magnetron sputtering of four pure metallic targets. The films are deposited in various argon-nitrogen gas mixtures on glass, silicon and sapphire positioned in the center and in the targets axis of a rotating substrates holder. Crystallographic structure evolution, as a function of the nitrogen content, is predicted by calculating the phase selection criteria. The theoretical predicted structures are consistent with X-ray diffraction analysis results. Without nitrogen, the films are amorphous, and by increasing the N-2 content in the gas mixture, they are single phased faces centered cubic (FCC). A {200} preferential growth of AlTiTaZr(-N) films is favored in the targets axis position with increased nitrogen flow rate, whereas those in the center position of substrates holder grow preferentially with {111} planes parallel to the substrates surface. Hardness and Young's modulus are improved with increasing of the nitrogen flow. The highest values were obtained for those in the targets axis position and reach 24.64 GPa and 148.4 GPa for the hardness and the Young modulus respectively. These films were annealed at 600 degrees C and 900 degrees C in vacuum and their thermal stability is discussed.

A Ti–23Nb–0.7Ta–2Zr–1.2O alloy (at %), called “gum metal”, was deposited by direct-current magnetron sputtering (DCMS) on an under layer of copper. By varying the working pressure during the deposition, columnar TNTZ (Ti–Nb–Ta–Zr) nanoarchitectures were obtained. At low working pressures, the upper layer was dense with a coarse surface (Ra = 12 nm) with a maximum height of 163 nm; however, the other samples prepared at high working pressures showed columnar architectures with voids and an average roughness of 4 nm. The prepared coatings were characterized using atomic force microscopy (AFM) for surface topography, energy dispersive X-ray spectroscopy (EDX) for atomic mapping, scanning electron microscopy (SEM) for cross-section imaging, contact angle measurements for hydrophilic/hydrophobic balance of the prepared surfaces, and X-ray diffraction (XRD) for the crystallographic structures of the prepared coatings. The morphology and the density of the prepared coatings were seen to influence the hydrophilic properties of the surface. The antibacterial activity of the prepared coatings was tested in the dark and under low-intensity indoor light. Bacterial inactivation was seen to happen in the dark from samples presenting columnar nanoarchitectures. This was attributed to the diffusion of copper ions from the under layer. To verify the copper release from the prepared samples, an inductively coupled plasma mass spectrometer (ICP-MS) was used. Additionally, the atomic depth profiling of the elements was carried out by X-ray photoelectron spectroscopy (XPS) for the as-prepared samples and for the samples used for bacterial inactivation. The low amount of copper in the bulk of the TNTZ upper layer justifies its diffusion to the surface. Recycling of the antibacterial activity was also investigated and revealed a stable activity over cycles.

The microstructural change of a thermal oxidation on a PM2000 superalloy was investigated after a 48 h isothermal heat-treatment. The oxides (transitions aluminas, [Formula: see text]-alumina and mixed oxides) were characterized using the Raman spectroscopy, the Photoluminescence (PL) spectroscopy, MEB observations and the X-ray diffraction for temperatures between 600°C and 1200°C. The X-ray diffraction results under conventional incidence conditions make it possible to estimate the crystallites size and the specific surfaces of the [Formula: see text]-alumina. The PL analyses at various excitation wavelengths (200[Formula: see text]nm, 234[Formula: see text]nm, 326[Formula: see text]nm and 532[Formula: see text]nm) provide important information on the existing defects (intrinsic and extrinsic) according to the oxidation temperature. The Raman spectroscopy ([Formula: see text].18[Formula: see text]nm) gives the various signatures of the various alumina generated ([Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]-Al2O3).