High Entropy Alloys Based on Nitrides of Refractory Metals – a New Solution for Protective Coatings on the Instruments Working at High Temperatures

The coatings based on (Ti-Al-Zr-Nb-Y)N and (Ti-Zr-Hf-V-Nb-Ta)N were obtained by means of vacuum-arc deposition from the cathodes based on Ti+Al+Zr+Nb+Yand Ti+Zr+Hf+V+Nb+Tasystems in the atmosphere of nitrogen. Their physical and mechanical properties, as well as tribotechnical characteristics have been studied. The coatings are characterized by a columnar structure and their hardness reaches 51.02GPa. The adhesion strength of the coatings has also been studied, the coefficient of friction of the system “coating – Al2O3“ is 1.1.The results of tribological tests at high temperature showed that at 460 °C coatings had greater wear resistance, lower coefficient of friction compared to similar tests of coatings at 20 °C.These coatings are perspective as protective coatings for friction pairs and cutting tools

Comparing the Tribological Properties of the Coatings (Ti-Hf-Zr-V-Nb-Ta)N and (Ti-Hf-Zr-V-Nb-Ta)N + DLC

The paper compares the tribological characteristics of the coatings (Ti-Hf-Zr-V-Nb-Ta)N and (Ti-Hf-Zr-V-Nb-Ta)N + DLC obtained by means of vacuum-arc deposition method. Coefficients of friction for nitride coatings (Ti-Hf-Zr-V-N-Ta)N have an average value of 1.06; for nitride coatings with DLC the value was 0.5 in the beginning, and then decreased to 0.14. To achieve high performance for functional coatings consisting of two layers - the bottom - and top-nitride DLC it is necessary to ensure the formation of a layer of solid lubricant in the areas of actual contact while retaining the structure of the coating

Formation of Biphasic State in Vacuum-Arc Coatings Obtained by Evaporation of Ti-Al-Zr-Nb-Y Alloy in the Atmosphere of Nitrogen

By means of X-ray diffraction, transmission and scanning electron microscopy, energy dispersive spectroscopy and indentation methods, the effect of nitrogen atmosphere pressure on composition, structure and hardness of vacuum-arc (Ti-Al-Zr-Nb-Y)N coatings during the deposition process has been studied. The two-phase state of the coating with solid-solution metal component (bcc lattice) and nitride phase (fcc lattice) have been formed. Increasing the pressure of nitrogen atmosphere leads to the increase of nitrogen component in the coating as well as to increase of the ordering regions size, allowing to achieve the hardness of H 49 GPa at a pressure of P 0.5 Pa. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3446

Structure, Substructure, Hardness and Adhesion Strength of Multiperiod Composite Coatings MoN / CrN

A comprehensive study of the influence of the thickness of the layers, Us and PN on the structural engineering to obtain high mechanical properties in multilayer composite MoN / CrN vacuum-arc coatings has been conducted by means of scanning electron microscopy with energy analysis, X-ray diffraction studies microindentation and scratch testing methods. It has been determined that in the studied PN (2- 30) 10 – 4 Torr, the content of nitrogen in the coatings varies from 6.3 to 33 at. %, which leads even at the greatest nitrogen content to the formation of lower phase by nitrogen, -Mo2N and isostructural CrN with the vacant sites in the nitrogen sublattice. The increase of thickness of the layers applied on the substrate in a stationary state promotes the increase of nitrogen content. Along with this, the lowest microdeformation and the average size of crystallites are formed at Ub – 300 V, which defines the achievement of greater hardness of 35 GPa and high adhesion strength, which resists the destruction, Lc5 187.6 N

Physical and Mechanical Properties of (Ti-Zr-Nb)N Coatings, Fabricated by Vacuum-Arc Deposition

The coatings based on (Ti-Zr-Nb)N were fabricated by vacuum-arc deposition of the Ti+Zr+Nb cathodes in the nitrogen atmosphere. Their physical and mechanical properties as well as tribological characteristics have been studied. The coatings are characterized by a columnar structure, their hardness reaches 44.57 GPa. The adhesion strength of coatings reaches 66.77 GPa, the friction coefficient of the «cover – Al2O3» is 1.1. It has been determined, that the hardness of the investigated coatings significantly depends on the pressure of the reaction gas. The coatings are promising as protective coatings for friction pairs and cutting tools

About Peculiarities of the Influence of the Negative Bias Potential Applied to the Substrate During the Deposition Process on the Structural State and Properties of the Multilayer system MoN-CrN

Applying transition metal nitrides of Mo and Cr, which are characterized by a relatively low heat of formation, as the components of the multilayer coating, the possibilities of elemental and structural engineering of vacuum-arc coatings under the influence of the bias potential Us and the reaction gas pressure PN are revealed. It was found that at a relatively small thickness of the layers of nanometer range, which provides superhard state of the coatings, the supply of Us with the value of above the critical leads to a drop in hardness, which can be explained by mixing of layers at the interphase boundary

Physical and Mechanical Properties of (Ti-Zr-Nb)N Coatings, Fabricated by Vacuum-Arc Deposition

The coatings based on (Ti-Zr-Nb)N were fabricated by vacuum-arc deposition of the Ti+Zr+Nb cathodes in the nitrogen atmosphere. Their physical and mechanical properties as well as tribological characteristics have been studied. The coatings are characterized by a columnar structure, their hardness reaches 44.57 GPa. The adhesion strength of coatings reaches 66.77 GPa, the friction coefficient of the «cover – Al2O3» is 1.1. It has been determined, that the hardness of the investigated coatings significantly depends on the pressure of the reaction gas. The coatings are promising as protective coatings for friction pairs and cutting tools

About Peculiarities of the Influence of the Negative Bias Potential Applied to the Substrate During the Deposition Process on the Structural State and Properties of the Multilayer system MoN-CrN

Applying transition metal nitrides of Mo and Cr, which are characterized by a relatively low heat of formation, as the components of the multilayer coating, the possibilities of elemental and structural engineering of vacuum-arc coatings under the influence of the bias potential Us and the reaction gas pressure PN are revealed. It was found that at a relatively small thickness of the layers of nanometer range, which provides superhard state of the coatings, the supply of Us with the value of above the critical leads to a drop in hardness, which can be explained by mixing of layers at the interphase boundary

Structure, Substructure, Hardness and Adhesion Strength of Multiperiod Composite Coatings MoN / CrN

A comprehensive study of the influence of the thickness of the layers, Us and PN on the structural engineering to obtain high mechanical properties in multilayer composite MoN / CrN vacuum-arc coatings has been conducted by means of scanning electron microscopy with energy analysis, X-ray diffraction studies microindentation and scratch testing methods. It has been determined that in the studied PN (2- 30) 10 – 4 Torr, the content of nitrogen in the coatings varies from 6.3 to 33 at. %, which leads even at the greatest nitrogen content to the formation of lower phase by nitrogen, -Mo2N and isostructural CrN with the vacant sites in the nitrogen sublattice. The increase of thickness of the layers applied on the substrate in a stationary state promotes the increase of nitrogen content. Along with this, the lowest microdeformation and the average size of crystallites are formed at Ub – 300 V, which defines the achievement of greater hardness of 35 GPa and high adhesion strength, which resists the destruction, Lc5 187.6 N

The effects of Cr and Si additions and deposition conditions on the structure and properties of the (Zr-Ti-Nb)N coatings

In this study, (Zr-Ti-Nb)N, (Zr-Ti-Cr-Nb)N and (Zr-Ti-Cr-Nb-Si)N nitride coatings were obtained using a well-developed vacuum arc deposition. The systematical investigations demonstrate that the chemical composition, microstructure, and properties of the coatings intimately rely on the deposition parameters (pressure of working gas and substrate bias). Effects of Cr and Si additions on microstructure and mechanical properties of the (Zr-Ti-Nb)N coatings have been investigated using scanning electron microscopy (SEM) equipped with energy dispersive spectrum (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscope (TEM), hardness measurements and adhesion testing. First-principles band-structure calculations and Gibbs-Rosenbaum triangle representation have been used to investigate the elemental and phase compositions in nitride coatings. The multi-component (Zr-Ti-Cr-Nb-Si)N and (Zr-Ti-Nb)N coatings are found to be a simple face-centered cubic (FCC) solid solution. For the coatings without Si, the structure is mainly composed of TiN fcc phase and Cr2N trigonal modification. The hardness values were in the ranges (24–42 GPa). The (Zr-Ti-Nb)N, (Zr-Ti-Cr-Nb)N coatings provided the best adhesive strength in different conditions. The (Zr-Ti-Cr-Nb-Si)N coatings exhibited the worst adhesive strength, which may be attributed to the relative low hardness