Multicomponent Coatings Research Articles

Microstructure and mechanical, electrical, and electrochemical properties of sputter-deposited multicomponent (TiNbZrTa)Nx coatings

A series of (TiNbZrTa)Nx coatings with a thickness of ~1.1 μm were deposited using reactive magnetron sputtering with segmented targets. The deposition temperature was varied from room temperature to 700 °C resulting in coatings with different microstructures. The coatings were characterized by electron microscopy, atomic force microscopy, compositional analysis, and X-ray diffraction. Effects of the deposition temperature on the electrical, mechanical and corrosion properties were studied with four-point probe, nanoindentation and potentiodynamic polarization measurements, respectively. X-ray photoelectron spectroscopy (XPS) analyses reveal a gradual change in the chemical state of all elements with increasing growth temperature from nitridic at room temperature to metallic at 700 °C. A NaCl-type structure with (001) preferred orientation was observed in the coating deposited at 400 °C, while an hcp structure was found for the coatings deposited above 400 °C. The resistivities of the TiNbZrTa nitride coatings were found to be around 200 μΩcm. In 0.1 M H2SO4 aqueous solution, a corrosion current density of 2.8 × 10−8 A/cm2 and a passive behaviour up to 1.5 V vs. Ag/AgCl were found for the most corrosion resistant coating. The latter corrosion current is about two orders of magnitude lower than that found for a reference hyper-duplex stainless steel.

Effect of interlayer design on the mechanical properties of AlTiCrN and multilayered AlTiCrN/TiSiN hard coatings

The adhesion strength and mechanical properties of hard coatings on substrates can be improved by adding an interlayer, which is also known as an adhesion, buffer, or seed layer. Cathodic-arc deposition (CAD) of hard coating often results in residual stresses, and the optimized design of the hard coating interlayer helps to reduce residual stress and improve mechanical properties, which is expected to extend the useful life of high speed precision stamping die applications. AlTiCrN transition metal nitride has been used as a protective hard coating because of its high hardness (~36 GPa) and resistance to high temperature oxidation up to 1100 °C. In this study, multicomponent hard coatings of AlTiCrN and AlTiCrN/TiSiN, which in the form of AlTiCrN/TiSiN multilayers, were deposited by cathodic-arc deposition. During the coating process, gradient TiN and CrN were deposited, respectively, as interlayers with different structures to control the residual stress and adhesion strength between the coatings and substrates. AlTiCr and TiSi alloy targets were used to deposit hard AlTiCrN/TiSiN coatings. The multicomponent AlTiCrN/Ti and AlTiCrN/Cr with Ti and Cr interlayers showed high residual stresses of −8 GPa and −8.4 GPa, respectively. The multilayered AlTiCrN/TiSiN coating with intermediate CrN and transition AlTiN/CrN multilayers under the top AlTiCrN/TiSiN multilayers possessed the lowest residual stress (−3 GPa). The residual stress changed by modifying interlayer configuration before the top AlTiCrN/TiSiN multilayers. The design of AlTiCrN/TiSiN multilayered coatings with interlayers of CrN and AlTiCrN/CrN can decrease residual stress and possessed good impact fatigue performance, which can be effective to reduce damage and cracking of hard coatings during cyclic impact loading.

Effect of SiO2 Nanoparticles Addition on Tribological and Electrochemical Behaviors of Ni–P–MoS2 Multi-Component Coatings after Heat Treatment

The tribological and electrochemical properties of various nanocomposite coatings of Ni–P–MoS2–SiO2 have been investigated. Such coatings were made by the electroless method and then heated at 400°C for 1 h. The amount of SiO2 nanoparticles was a factor which changed Ni–P–MoS2 coatings characteristics. In addition to microstructure evaluations and the phase detection, the microhardness, the friction coefficient, and wear behavior were studied for various coatings. Field emission scanning electron microscopy images demonstrated that SiO2 nanoparticles were distributed uniformly in the Ni–P–MoS2 matrix. The obtained results showed that when the concentration of SiO2 nanoparticles in the deposition bath increased from 5 to 20 g/L, then the microhardness and the wear resistance increased as well. Besides, the friction coefficient reached the lowest value of 0.05. For nanocomposite coatings, the ratio of the friction coefficient to the square hardness was a proper parameter which could predict the wear behavior. Additionally, energy dispersive spectroscopy results showed that the content of SiO2 nanoparticles in such coatings increased from 4.9 to 11.4 wt %. Corrosion tests demonstrated that the best corrosion resistance was observed for the nanocomposite coating when the concentration of SiO2 nanoparticle was 20 g/L.

Effect of Surface Pre-Treatment on Adhesive Strength of Multi-Component Vacuum-Arc Coatings

The results of investigations of multi-component nanostructured coatings of (TiAlSiY)N/CrN type are presented. The influence of different variants of substrate surface pretreatment on adhesive strength and hardness of coatings was studied. Pre-treatment of samples was carried out in plasma of two-stage gas discharge according to various technological schemes. Except for ion-plasma purification, some samples were pretreated with a sublayer of chromium within 5 minutes. The coatings were formed by a vacuum-arc deposition method at simultaneous spraying of two cathode targets. The first cathode is made of chromium, and the second cathode is made of multicomponent Ti - Al - Si - Y alloy obtained by vacuum-arc remelting of powder mixture of the mentioned elements. The coatings were deposited on polished stainless-steel substrates at negative 280 V bias potential. The geometry of the unit and its elements, as well as technological characteristics of the processes of evaporation-condensation were selected so that at a speed of rotation of samples 8 revolutions per minute the formation of the coating with a total thickness of about 9.0 microns occurred in approximately 60 minutes. The analysis of the composition of the coatings shows that the content of elements in the coating differs greatly from the content of elements in the sprayed cathodes. The X-ray diffractometry has shown that all deposition modes are characterized by the formation of phases with cubic (fcc) crystal lattice in both phase layers of multilayer coatings. In the layers formed at spraying of TiAlSiY alloy, a multi-element disordered solid solution (TiAlSiY)N with a crystal lattice of NaCl type and a lattice parameter of 0.4241 nm, as well as chromium mononitride CrN with a lattice parameter of 0.4161 nm, is determined. It has been established that preliminary formation of a chromium sublayer on the substrate leads to significant changes in adhesive strength of multi-component coatings compared to coatings without a sublayer.

Filtered cathodic vacuum arc deposition (FCVAD) technology as method for creation of nanostructured multicomponent modifying coatings for wide application range

Modern production requires the development of new structural materials with improved mechanical and chemical properties. One of the methods to create such materials is to deposit solid modifying coatings onto softer and more ductile substrates. Moreover, such coatings may also have good barrier properties with respect to chemical interaction and interdiffusion. The use of nanolayer and superlattice architecture is an effective method to create such modifying coatings with a unique combination of extremely high hardness (up to 80 GPa), good brittle fracture resistance, as well as barrier properties. The considered method of filtered cathodic vacuum arc deposition (FCVAD) makes it possible to synthesize coatings with controlled nanolayer thicknesses from 2 up to 100 nm, with the total coating thickness of up to 20 µm. Another important feature of the considered method is the possibility to generate multicomponent and high-entropic coatings for the wide application range (cutting tools, medical devices, friction pairs, etc.). The possibility to create a dense coating structure, free of microdroplets and micropores, makes it possible to use the proposed technology to create insulating coatings for medical purposes. The additional possibility is the creation of both biologically passive and biologically active coatings (in particular, coatings containing micro- or nanoparticles of silver).

Formation and Physical Properties of Multicomponent Coatings Sputter-deposited from Co-Cr-Ni-Ti-Zr-Hf-Ta-W-C Segmented Target

Formation and Physical Properties of Multicomponent Coatings Sputter-deposited from Co-Cr-Ni-Ti-Zr-Hf-Ta-W-C Segmented Target

Synthesis of Si-Y Coatings on Nb in Fluoride-Chloride Molten Salts

The preparation of multicomponent coatings based on silicon and yttrium on the niobium substrate was investigated. Y-Si/NbSi2 coatings on the Nb substrate by currentless deposition in molten salts were produced. The preparation of NbSi2 layers is carried out in NaF-NaCl-Na2SiF6 melts with the addition of Si powder. The preparation of Y-Si layers is carried out in NaCl-KCl-YF3 melts containing Y powder. Coating samples are studied using SEM. It is established that sequentially synthesized coatings are characterized by a two-layer structure. Using the EDS method, the chemical composition of the obtained layers is established: Y – 26.68; Nb – 62.55; Si – 10.76 wt. %. The oxidation test of the obtained coatings Y-Si/NbSi2 on Nb samples is performed. It is found that testing at 1200 ˚C for 2 hours leads to a mass loss of 62 mg/cm2·h.

RESEARCH OF RESIDUAL STRESSES ON COATINGS OBTAINED USING COMPOSITE POWDER MATERIALS

The purpose of the work is to conduct research on the nature of the distribution of residual stresses of coatings on structural materials obtained using composite saturating media. Residual stresses appear after chemical-thermal treatment during cooling as a result of the elastic interaction of the diffusion layer and the core having different volumes and coefficients of thermal expansion. The ratio of the volumetric characteristics of the layer and the core also affects the magnitude of the residual stresses in the surface layer. Residual stresses significantly determine the possibility of practical use of diffusion coatings. Moreover, the magnitude, sign and nature of their distribution affect the adhesion strength of the coating to the hardened material. Residual stresses arising in the diffusion layer are often the cause of microcracks and peeling of the coating. As a rule, the level of residual stresses is higher, the greater is the difference in the temperature conditions of production, the thermophysical and physico-mechanical properties of the base materials and the protective coating. One way to influence the nature of the distribution of internal stresses in protective coatings is to dope them. The nature of the distribution of residual stresses over the thickness of multicomponent coatings indicates that their alloying with boron, chromium, and aluminum makes it possible to obtain FeB and Fe 2 B phases, which are alloyed with silicon, chromium, and aluminum. Residual compressive stresses from 360 to 410 MPa appear on the surface of the layers. The boride phase Fe 2 B is in a state of volumetric stress with a significant gradient of stresses in depth. It was found that in the process of producing multicomponent coatings doped with chromium, aluminum, boron, titanium and tungsten, the value of the residual compressive stresses increases with increasing carbon content in the substrate. So when the carbon content in the substrate changes from 0.02% C to 0.8% C when alloyed with chromium and aluminum, they are 110 and 260 MPa; when alloying with chromium, aluminum, boron – 200 and 410 MPa; when alloying with chromium, aluminum and titanium – 20 and 330 MPa; chromium, aluminum and tungsten – 45 and 210 MPa, which is associated with a large difference in the physicomechanical properties of the base material and the protective coating.

Supersonic particle deposition as an additive technology: methods, challenges, and applications

This paper presents a review of recent research inventions in the field of supersonic particle deposition (SPD) additive manufacturing (AM) technology. The SPD, also known as cold spray, is a coating technique that has gained popularity recently because of its ability to apply multi-component coatings. The SPD has the potential to revolutionize the global parts manufacturing and logistics landscape. The state-of-the-art, rapidly emerging cold spray manufacturing technology is an alternative to traditional additive manufacturing (AM) based on powder melting. It enables the rapid fabrication of parts that have properties similar to the parts developed by conventional manufacturing. In this paper, the history and process of SPD are explained. A broad background of metallic SPD AM is provided. SPD parameters, including substrate and particle properties, are discussed. Common challenges in creating consistent SPD coatings as well as challenges specific to metal and ceramic SPD are discussed. This paper explores the material science, processes, and performance gain. Several applications of SPD, including nuclear, aerospace, and electrical industries, are discussed.

Thermal Transformation of the Surface of Mn-, W-Containing Plasma Electrolytic Oxide Coatings on Titanium

Thermal behavior of the surface of coatings formed on titanium specimens by plasma electrolytic oxidation (PEO) in phosphate—borate—tungstate electrolyte containing manganese acetate as a precursor was studied. High-temperature annealing in air allows directional obtaining of ensembles of nano- and microcrystals of definite composition and geometry on the surface of specimens with multicomponent PEO coatings.

Structural and Tribological Properties of Multicomponent Coatings on 45 and 210Cr12 Steels Obtained by Electrospark Deposition with WC-B4C-TiB2-Ni-Cr-Co-B-Si Electrodes

In the present work, a new type of wear-resistant coatings obtained on steels by contactless electro-spark deposition using a rotating electrode and by electrical discharge deposition with a vibrating electrode has been studied. Electrodes have been obtained by pressing and sintering multi-component powder mixtures of hard metal WC-Co with additives of super-hard and refractory compounds of B4C and TiB2 and semi-self-fluxing alloys Ni-Cr-B-Si. High density coatings, with a thickness up to 80 μm and micro hardness up to 17.0 GPa, have been obtained. The roughness, thickness, composition, and structure of the coatings thus obtained have been studied by X-ray diffraction, scanning electron microscopy, and electro-spark deposition. The influence of micro-geometric parameters, composition and structure of coatings on their tribological properties and wear resistance were studied by comparative tests of friction and abrasion wear. The friction tests showed that the wear of the coated steel surfaces is up to 5 times lower compared to the uncoated those. On the base of the experimental data, a comparative analysis of the coatings obtained by the two methods have been made. Appropriate regimes and conditions for deposition of coatings with optimal properties have been defined.

ОСОБЛИВОСТІ ПОБУДОВИ СИСТЕМ ЕЛЕКТРОЖИВЛЕННЯ ІНВЕРСНОЇ МАГНЕТРОННОЇ РОЗПОРОШУВАЛЬНОЇ СИСТЕМИ ДЛЯ ФОРМУВАННЯ БАГАТОКОМПОНЕНТНИХ ПОКРИТТІВ (ПРАКТИЧНІ АСПЕКТИ РОЗРОБКИ РЕЗИСТИВНИХ ЛАНЦЮЖКІВ У СКЛАДІ ГЕНЕРАТОРА ПЛАЗМИ)

The consideration of the features of constructing the power supply system of a pilot industrial-technological installation for applying multicomponent coatings by the ion-plasma method is continued. The main attention is paid to the practical aspects of developing controlled resistive circuits connected to various elements of the power supply circuit of a technological plasma generator. It is noted that the control of the operation mode of the technological installation is provided by changing the resistance of these chains by the corresponding automated system. A mathematical expression is proposed in the form of a polynomial for the resistance of chains, which meets the requirements for a research installation and the condition for minimizing the number of resistors in a separate chain. The structure of the chain is considered as a combination of the required number of cells. Each of them differs from the others not only in the connection scheme of the resistors but also in their resistance. An algorithm is proposed for determining the nominal resistance, heat loss power, the number of resistors and the circuitry for their connection. For example, a diagram and the main technical characteristics of a chain connected to a group of target cathodes from tungsten are given. Such cathodes are used in the formation of nanostructured and multifunctional coatings of tungsten carbide on the surface of metal parts. Particular attention is paid to the control elements in the individual cells of the technological plasma generator. The analysis of requirements for control elements such as semiconductor switches and electromagnetic relays is carried out. It is noted that these requirements are met by conventional (not high-voltage) electromagnetic relays of domestic production, provided that their contacts are connected in series with each other. Attention is drawn to the need to prevent the formation of an electric arc when the relay contacts open, can be achieved by including a resistor and a capacitor in series with the control element. It is also important to use means of forced air cooling of the resistive chain block.

Physical chemical study of zein and arabinogalactans or glucuronomannans polyelectrolyte complexes and their film-forming properties

Four gum exudates, the arabinogalactans gum Acacia (GA) and Acacia mearnsii gum (GN) and the glucuronomannans gum Ghatti (GG) and Vochysia thyrsoidea gum (VT) were used to obtain polyelectrolyte complexes (PECs) with zein, a corn protein. GA and GG are commercially available, whereas GN and VT are obtained from Brazilian trees. The polysaccharides differ in their monosaccharide composition and protein content. The PECs were prepared by desolvation or nanoprecipitation methods, therefore the type of gum and the preparation method were related to the PECs physical chemical properties and their film-forming characteristics. The higher yields of complexation were obtained by desolvation, which also lead to the larger aggregates due to the diffusion impairments inherent to this method. The different chemical properties of polysaccharides influenced the yielding of complexation. The spatial availability of uronic acid units contributed to make GG the best pair for zein, followed by VT, GN, and GA, according to the carbohydrate coacervation yield. Concerning the protein yield, PECs with GA retained more zein, followed by GG, GN, and VT. Despite all PECs presented good film-forming properties, the glucuronomannans formed the most homogeneous ones. The films surface energies were obtained by the Lifshitz-van der Waals/Lewis acid-base (LWAB) model, being possible to predict that these coatings would adhere more favorably to strawberry, independently of the polysaccharide used. Therefore, it was demonstrated that the polysaccharides extracted from A. mearnsii and V. thyrsoidea trees can be used in multicomponent edible coatings as their commercial analogues, respectively gum Arabic and gum Ghatti.

MULTICOMPONENT Al-BRONZE COATINGS THERMALLY SPRAYED ONTO TIN BRONZE SUBSTRATE: MICROSTRUCTURAL, MECHANICAL AND CORROSION CHARACTERIZATION IN A 3.5% NaCl SOLUTION

In this work, multicomponent Al-bronze alloys coated Tin-Bronze substrates, fabricated by thermal flame spraying, are characterized by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy. Mechanical characterizations are also presented: microhardness measurement and friction coefficient. The electrochemical behavior of tin-bronze samples uncoated and coated with multicomponent Al-Bronze coatings is studied in NaCl 3.5% solutions using potentiodynamic polarization curves and polarization resistance measurements. The microstructure of the coatings has a lamellar morphology. Each lamella is constituted of a mixture of Cu3Al globular micro precipitates ([Formula: see text]-phase) uniformly distributed over the solid solution matrix ([Formula: see text]-Cu). An oxide based on Cu, Al and Fe is also present in very low concentration. [Formula: see text]-phase is unexpected because it is present only above 570∘C in the Cu-Al phase diagram. Compared with the tin-bronze substrate, multicomponent Al-bronze coatings show a friction coefficient three times lower and have a better electrochemical behavior in 3.5% NaCl solution.

ОСОБЛИВОСТІ ПОБУДОВИ СИСТЕМИ ЕЛЕКТРОЖИВЛЕННЯ ІНВЕРСНОЇ МАГНЕТРОННОЇ РОЗПОРОШУВАЛЬНОЇ СИСТЕМИ ДЛЯ ФОРМУВАННЯ БАГАТОКОМПОНЕНТНИХ ПОКРИТТІВ (СПОСІБ УПРАВЛІННЯ ПРОЦЕСОМ РОЗПОРОШЕННЯ ТА ЙОГО ПРАКТИЧНА РЕАЛІЗАЦІЯ)

It's shown the necessity to use functional coatings in engineering, which can be formed in many layers and contain a number of components what based on the analysis of literature data about ways to ensure the required resource of machine parts and mechanisms. Existing technologies and the corresponding equipment require the prefabricating of the alloys which the coatings are formed. This significantly limits the control of the coatings' composition. It's shown the advantage of ion-plasma technologies developed at National Aerospace University "Kharkiv Aviation Institute" over the existing technologies. In particular, due to the spraying of a large number of cathodes-targets, these technologies allow the formation of multicomponent coatings of almost any composition. When implementing ion-plasma technology for the formation of coatings, a decisive role plays the generator of the flow of particles of the coating material. It has been proposed to supply voltage to each generator element through a chain of resistors, the total resistance of which is regulated by the control system of the corresponding program to improve the power supply system of such a generator. Such an approach to the improvement of the power supply system of the technological generator of the coating material is implemented in the developed laboratory experimental-industrial process plant for the formation of a model coating of tungsten carbide. It was considered two possible schemes for creating resistive chains with regulated resistance. It was selected the scheme, which consists of a smaller number of elements. The important role of any resistive chain in the operation of the technological generator control system has been determined. It was proposed the optimal choice of the nominal values of the resistors included in the chain. The optimal choice of the nominal values of the resistors included in the chain has been proposed. The conducted analysis of experimental data carried out by the authors suggests that each such chain should have individual features, in particular, the boundaries and the step of resistance, the maximum power of heat losses. These and other parameters are usually determined experimentally.

Corrosion, wear, and friction behavior of a number of multilayer two-, three- and multicomponent nitride coatings on different substrates, depending on the phase and elemental composition gradient

Abstract In this paper, single-layer coatings based on two-component TiN and ZrN, three-component (Ti,Zr)N and (Ti,Al)N and four-component (Ti,Zr,Al)N nitrides were obtained by pulsed magnetron sputtering, DC magnetron sputtering, cathodic arc evaporation, and com-bined method at various process parameters. The protective properties of these coatings in 0.3% NaCl, 3% NaCl, and 5% NaOH were related with their structure, texture, thickness, phase and elemental composition. The two-component nanostructured coating TiN based on phase c-TiN obtained by pulsed magnetron sputtering decreases the corrosion and passive current in 3% NaCl by over 2500 times. The stoichiometric nanostructured coating ZrN deposited by cathodic arc evaporation slows down the corrosion in the 5% NaOH by over 3000 times, and the passive current – by 2000 times. The single-layer three-component (Ti,Al)N and four-component (Ti,Zr,Al)N coatings exhibit, as a rule, worse corrosion resistance compared to the two-component TiN, ZrN and three-component (Ti,Zr)N coatings. It was found that the composition gradient inside the single-layer coating leads to a deterioration of its protective properties. Based on alternating TiN, ZrN, and (Ti,Zr)N layers optimized by structure and composition five multilayer coatings have been developed. The structure and composition gradient of multilayer coatings was received by changing of material and deposition method of layers. It has been experimentally proved that the obtained multilayer nanostructured coatings possess a complex of high corrosion, physicomechanical and tribological properties.

Effect of fructose-containing feedstocks on the microstructure of multicomponent coatings deposited by suspension plasma spraying

This work addressed to investigate the use of fructose as an additive in the water-based suspension feedstock of a Y-TZP/Al2O3/SiC multicomponent coating manufactured by suspension plasma spraying. The effect of fructose on suspension rheology and surface tension and on the microstructure and thermal conductivity of the resulting coatings was assessed.It was observed that addition of fructose slightly affected the rheological behaviour of the suspensions while a strong decrease in the surface tension of water occurred. The fructose addition led to the development of columnar-like structures, probably associated with its effect on surface tension. X-ray diffraction patterns in the final coating displayed that crystallinity of tetragonal zirconia formed when fructose was added whereas silicon carbide crystalline phase was practically preserved. The determination of thermal conductivity showed that the formation of a controlled columnar structure along with inter-columnar porosity can be beneficial for thermal insulation.

Multi-Criteria Assessment of Physical Properties of Nanostructured Decorative Protective Coatings

One of the most efficient methods of improving the durability of a product is applying different coatings to the working surface. The quality of decorative and protective coatings is determined by the quality of workpiece surface (roughness, texture, etc.), preparation of workpiece surface (contamination, presence of oxide films, degree of surface activation by ion etching), and the production methods. The article presents the results of a series of experiments in creating multi-component ion-plasma coatings by vacuum deposition on Ti-Al basis. A series of experiments aimed at obtaining single-layer coatings have been carried out using a certain pattern of sputtering in argon and nitrogen environment. The obtained coatings can have a wide variety of colors. Different properties of the created coatings including spectral characteristics, reflection coefficient at different angles of incidence of light as well as chemical composition have been studied. The energy-dispersive electron microprobe analysis revealed the dependence of coating reflection coefficient and spectral characteristics on the chemical composition.

Technological features of Ti–Cr–B–N coatings formation by magnetron sputtering method in a direct current

The results of the study of the phase composition and physical and mechanical properties of multicomponent coatings Ti– Cr–B–N formed by magnetron sputtering at a constant current from composite targets are presented. The features of phase formation of coatings when spraying targets containing titanium diboride (TiB2) or boron nitride (BN) as a boron-containing component are studied. The conditions of deposition of coatings with microhardness up to 32 GPA and heat resistance up to 800 °C are established.

Vacuum rapid fabrication of (Nb,Ti,Cr)Si2 coatings with Mo, W addition: Microstructure and oxidation resistance at 1450 °C

In order to develop the oxidation-resistant coatings for Nb based alloy at high temperatures, multi-component silicide coatings, Si-Cr-Ti coatings with and without Mo or W addition, were fabricated by spark plasma sintering process. The sintered Si-Cr-Ti coating mainly consists of single NbSi2 phase with solid solution of Ti and Cr (i.e. (Nb,Ti,Cr)Si2), while MoSi2 or WSi2 are also found in the coatings with addition of Mo or W respectively. The oxidation resistance of the coatings was tested in air at 1450 °C for 24 h. The (Nb,Ti,Cr)Si2 coating shows insufficient protection and the formed complex oxides scale turns to powders. With adding Mo or W in the coatings, dense oxide scales are formed, and the W-added coating exhibits better oxidation resistance due to the formation of a more continuous and thinner SiO2 layer.