The results of studies of the properties of CA-PVD Ti-Al-Ni-N coatings deposited on widely used carbide alloys of the WC-Co, WC-TiC-Co, WC-TiC-TaC-Co groups and carbon steel are presented. It has been shown that the hardness and Young's modulus of the coatings on different substrates differ by up to 1.5 times, even though there is no significant difference in composition. The formation of globular aggregations on cell ridges, which is a characteristic feature of the morphology of coatings on steel substrates, and the presence of multilevel (stepped) structure were observed. The difference in CSR, microstrain and lattice period values for the nitride phase in the coatings on the substrates has been established. From the point of view of differences in thermal diffusivity of substrates, features of morphology and substructure of coatings are explained. The differences in the properties of coatings are also associated with the implementation of tensile macrostresses on steel in comparison with compressive stresses on carbide substrates. Tensile macrostresses and macrolayering are the reasons for the relatively low level of strength (2-3 times) of adhesion of the coating to tool steel compared to coatings on carbide substrates. At the same time, a decrease in the shear strength of the coating material on a steel substrate due to macro-layering may be the reason for the relatively low friction coefficient of this coating (similar to 0.5) compared to coatings on a carbide base (0.69-0.53). The work provides recommendations for the most effective use of Ti-Ni-Al-N coating on carbide alloys and carbon steel.

Abstract—The possibility of using Ti–Al–N, Ti–Al–Ni–N, Ti–Cr–Ni–N, and Ti–Cr–Ni–Mo–N coatings deposited by ion-plasma vacuum-arc deposition as protective on products made of steel 20Kh13, working in a friction pair with carbon fiber plastic of the UGET grade in contact with seawater, has been investigated. An improvement in the resistance properties of a steel surface is shown when using coatings of the Ti–Al–Ni–N, Ti–Cr–Ni—N, and Ti–Cr–Ni–Mo–N systems. And the products without or with Ti–Al–N coating showed high friction wear rates (109.21 × 10–5 and 19.24 × 10–5 mm3/(N m), respectively), as well as active oxidation during electrochemical tests under conditions of interaction with a medium simulating seawater (3

The study shows the results of comparative resistance tests of a carbide cutting tool with (Ti,Al)N – Cu and (Ti,Al)N – Ni nanostructured arc-PVD coatings deposited on its working surfaces under conditions of continuous and interrupted cutting of 13Mn6 (09G2S) and 10Cr15Ni9Si3Nb1-SH (EP302-Sh) steels, respectively. Under milling conditions of 10Cr15Ni9Si3Nb1-SH steel, when using WC – Co (6 wt.% Co) inserts with (Ti,Al)N – Cu and (Ti,Al)N – Ni coatings, tool life increases by 3.1 and 1.7 times, respectively. When turning steel 13Mn6 using WC – Co inserts coated with (Ti,Al)N – Cu and (Ti,Al)N – Ni, tool life increases by 7.6 and 10.8 times, respectively, and cutting forces Fz, Fx, Fy decrease nearly by 20 %. This effect is determined by the presence of a nanostructure in the formed coatings, the presence of a highly hard ceramic component and ductile metal, which determine their hardness (more than 35 GPa) and fracture toughness (the relative work of plastic deformation during indentation is more than 60 %), increased tribological characteristics (friction coefficient ~ 0.5 according to comparison with uncoated carbide ~ 0.7). The study noted an increased resistance of (Ti,Al)N – Ni coatings on a hard alloy to continuous cutting of steel, which is determined by their high hardness and lower friction coefficient compared to (Ti,Al)N – Cu coatings, which are characterized by better performance in interrupted cutting operations, where the determining value of resistance is the fracture toughness.

В работе исследованы фотоэлектрохимические и фотокаталитические свойства пористых материалов на основе полых микросфер α-Fe 2 O 3 , характеризующихся наличием оборванных магнитных связей Fe–O–Fe, обусловленных повышенной концентрацией вакансий на границе стенка/закрытая пора. С использованием данного порошка шликерно-обжиговым методом при температуре изотермической выдержки 400°C были получены две серии пленочных образцов, нанесенных на стекло с токопроводящим слоем из суспензий двух составов: водный раствор Fe(NO 3 ) 3 + полые микросферы α-Fe 2 O 3 (серия 1 ) и водный раствор Fe(NO 3 ) 3 + полиэтиленгликоль + полые микросферы α‑Fe 2 O 3 (серия 2 ). Установлено, что пленки серии 2 имеют структуру с пространственно разделенными частицами различной дисперсности: наночастицы α-Fe 2 O 3 /полые микросферы α-Fe 2 O 3 , а пленки серии 1 преимущественно состоят из полых микросфер, объединенных "шейками", формирующимися в процессе термической обработки. Толщина пленок серии 2 составляла порядка 2 мкм, а серии 1 – 4 мкм. Структурные различия пленок двух серий оказывают существенное влияние на оптические свойства материала. Пленка серии 2 (3.50 × 10 5 м –1 ) имеет примерно в 2 раза больший коэффициент поглощения света в диапазоне длин волн 350–1500 нм в сравнении с пленкой серии 1 (1.75 × 10 5 м –1 ). Исследование фотоэлектрохимических свойств в водном растворе 0.1 M KOH показало, что потенциал начала анодной реакции для пленки серии 2 составил 0.87 В vs. Ag/AgCl, а для серии 1 – 0.97 В vs. Ag/AgCl. Для обеих пленок наблюдалось нетипичное увеличение плотности тока при длительном освещении светом при потенциале 1 В vs. Ag/AgCl, вызванное формированием на поверхности фотоанода Fe(IV). Фотокаталитические свойства материалов оценивались по скорости деградации метиленового синего. Константы скорости реакции ( k ) составили 0.015 и 0.018 мин –1 для пленок серий 1 и 2 соответственно против k для реакции без фотокатализатора 2.8 × 10 –4 мин –1 .

This article examines the impact of surface and near-surface layer properties of a hard alloy on the physico-mechanical and tribological properties of Mo–Ti–Ni–Si–Al–N CAPVD-coatings deposited on HG40 and HS123 cutting tools. In both cases, the coatings had similar composition, multilayer architecture, and nanograin structure, with crystallite sizes ranging from 6 to 10 nm. However, there were significant differences in the hardness, elasticity modulus, and relative work of plastic deformation between the coatings. Specifically, on HG40 substrates, the hardness, elasticity modulus, and relative work of plastic deformation were equal to 27.6 GPa, 647 GPa and 38.2 %, respectively, while on HS123 substrates, they were 34.2 GPa, 481 GPa and 46.2 %, respectively. Furthermore, coatings formed on HS123 hard alloy demonstrated superior wear resistance and stronger adhesion. This can be attributed to the presence of higher compressive macrostresses within the coating. The maximum value of this property, approximately 5.2 GPa, was achieved when deposed to HS123 hard alloy, whereas the coating applied to HG40 reached a maximum value of approximately 3.2 GPa. Additionally, a more extensive diffusion zone between the substrate and coating components, along with associated structural phase heterogeneity, was observed at the coating-substrate interface when applied to HS123 substrate.

Покрытия систем Zr–B–Si–C–Ti и Zr–B–Si–C–Ti–N впервые были получены методом ионно-плазменного вакуумно-дугового осаждения в остаточной атмосфере аргона и азота. Покрытие Zr–B–Si–C–Ti характеризуется аморфно-нанокристаллической структурой. Нанокристаллиты формировались в системе Ti–B–C, а аморфная составляющая структуры образована фазами Zr–B–C и Si–C. Покрытие второй системы имеет преимущественно аморфную структуру (степень аморфизации ~85–93%), которая формируется на основе нитрида титана с наличием связей Ti–B и Ti–C, карбоборнитрида (Zr x (C,N,B) y ), борида циркония и карбонитрида кремния.

The influence of nickel on the structure and properties of Ti-Cr-N ion-plasma coatings obtained by arc-PVD method has been studied. With a nickel content of up to 11.9 at. %, the coating consists of Cr 2 N, Ti1 – x Cr x N, and metallic Ni. Upon further increase in Ni concentration in the coating, intermetallic compound Ni3Ti is formed. The structure of the coatings was studied using the transmission electron microscopy. The coatings of Ti-Cr-N system are characterized by a columnar structure, in the columns of which Ti1 - x Cr x N and Ti 1 - y Cr y N (x > y) sublayers, being several nanometers thick and containing variable concentration of titanium and chromium, as well as Cr 2 N sublayers of about 25 nm are formed due to the complete solubility of TiN and Cr 2 N and the planetary rotation of the substrates, resulting in layer-by-layer stacking of the components of the evaporated cathodes. This structure remains intact in coatings of Ti-Cr-N-Ni system with a low nickel concentration (on the order of tenths of at. %). However, upon that, the column size refinement and an increase in biaxial compressive stresses from 6.7 to 9.7 GPa are observed, which results in an increase in hardness from 30 to 42 GPa. The coatings with a high nickel content are characterized by a multilayer architecture with an equiaxed polycrystalline structure of nanograins in layers. As Ni concentration increases, the hardness of the coating decreases to 16.7 GPa, which is associated with an increase in the fraction of relatively soft nickel in the coating and a decrease in macrostresses to -0.6 GPa. Upon that, the wear intensity increases from 3·10 -15 to 5·10 -15 m 3 /(N·m). The studied coatings of Ti–Cr–N and Ti–Cr–N–Ni systems are resistant to adhesive and cohesive destruction. With an increase in the nickel content upon measuring scratching, the destruction of the coatings occurs exclusively due to the plastic deformation.

— We have studied photoelectrochemical and photocatalytic properties of porous materials based on hollow α-Fe 2 O 3 microspheres, characterized by the presence of dangling magnetic Fe–O–Fe bonds due to an increased oxygen vacancy concentration on the wall/closed pore interface. Using such powder and firing slips at an isothermal holding temperature of 400°C, we obtained two series of thin-film samples on glass with a conductive layer from suspensions of two compositions: aqueous Fe(NO 3 ) 3 solution + hollow α-Fe 2 O 3 microspheres (series 1 ) and aqueous Fe(NO 3 ) 3 solution + polyethylene glycol + hollow α-Fe 2 O 3 microspheres (series 2 ). The films of series 2 were shown to have a structure with spatially separated particles differing in size: α-Fe 2 O 3 nanoparticles and hollow α-Fe 2 O 3 microspheres. The films of series 1 consisted predominantly of hollow microspheres connected by “necks” formed during heat treatment. The thickness of the films of series 2 was of order 2 μm and that of the films of series 1 was of order 4 μm. The structural distinctions between the films of the two series had a significant effect on the optical properties of the material. In the wavelength range 350–1500 nm, the absorption coefficient of the films of series 2 (3.50 × 10 5 m –1 ) was about twice that of the films of series 1 (1.75 × 10 5 m –1 ). Photoelectrochemical characterization in an aqueous 0.1 M KOH solution showed that the onset potential for the anodic reaction was 0.87 V vs. Ag/AgCl in the case of the films of series 2 and 0.97 V vs. Ag/AgCl in the case of series 1 . The films of both series showed an unusual increase in current density during prolonged illumination at a potential of 1 V vs. Ag/AgCl, due to Fe(IV) formation on the photoanode surface. Photocatalytic properties of the materials were assessed from the rate of methylene blue degradation. The reaction rate constant ( k ) was determined to be 0.015 and 0.018 min –1 for the films of series 1 and 2 , respectively, whereas the k of the photocatalyst-free reaction was 2.8 × 10 –4 min –1 .

The possibility of using arc-PVD coatings Ti – Al – N, Ti – Al – Ni – N, Ti – Cr – Ni – N and Ti – Cr – Ni – Mo – N as protective on the surface of products made of AISI 420 steel, operating in friction pairs with carbon fiber in contact with sea water. An improvement in the resistance properties of the surface is shown when using coatings of the Ti – Al – Ni – N, Ti – Cr – Ni – N and Ti – Cr – Ni – Mo – N systems. Whereas uncoated and Ti – Al – N coated steels exhibited high friction wear rates (109.21·10–5 and 19.24·10–5 mm3/(N·m), respectively) as well as active oxidation in electrochemical tests under conditions of interaction with a medium simulating sea water (3 % NaCl solution), the coatings Ti – Al – Ni – N, Ti – Cr – Ni – N and Ti – Cr – Ni – Mo – N was not shown significant wear during friction in tandem with UGET grade carbon fiber, and under the conditions of electrochemical tests, their use led to the phenomenon of self-passivation of coatings and the absence of pitting on the surface, which made it possible to conclude that their use as protective ones for operation in conditions of contact with sea water is highly effective.

We report a comparative study of the chemical and thermal stability and mechanical properties of arc PVD TiN and Ti0.97Al0.03N coatings. Heating the coatings in vacuum to 600 and 700°C has been shown to cause an increase in crystallite size and a decrease in biaxial macrostress, lattice parameter, and lattice strain. These effects are due to thermally activated structure restoration processes associated with annihilation of defects generated during the growth of the coatings. The stress relaxation rate in the Ti0.97Al0.03N coating is higher because it contains a higher defect density. At 700°C, the Ti0.97Al0.03N solid solution undergoes spinodal decomposition into TiN and AlN (FCC). Unlike those of the TiN coating, the hardness and the parameters H3/E2 and H/E of the Ti0.97Al0.03N coating remain essentially unchanged as the annealing temperature is raised to 700°C, which is due to dispersion hardening as a result of the spinodal decomposition. The coatings exhibit similar behavior in acidic and alkaline media, but Ti0.97Al0.03N has a somewhat higher oxidation resistance in air at 550°C.

Nanostructured Ti–Al–Mo–N and Ti–Al–Mo–Ni–N coatings with a layered architecture have been grown by arc PVD. We have determined deposition parameters (reaction gas (nitrogen) pressure and negative bias voltage applied to the substrate and determining the energy of incident particles) that enable the formation of a two-phase nitride (TiN + Mo2N) coating in the Ti–Al–Mo–N system and a nitride–metal (TiN + Mo2N + Ni) coating in the Ti–Al–Mo–Ni–N system. The addition of Ni to the composition of Ti–Al–Mo–N coatings leads to a decrease in the average grain size of the nitride phases from 35 to 12 nm and reduces the modulation period from 50 to 35 nm by limiting the growth of nitride nuclei. This is accompanied by a decrease in biaxial macrostress: from σ = –2.51 GPa in the Ti–Al–Mo–N coating to σ = –0.67 GPa in the Ti–Al–Mo–Ni–N coating.

Методом arc -PVD получены покрытия Ti–Al–Mo–N и Ti–Al–Mo–Ni–N, характеризующиеся наноструктурой и слоистой архитектурой. Установлены значения параметров осаждения (давления реакционного газа-азота и отрицательного потенциала смещения, подаваемого на подложку, определяющего энергию напыляемых частиц), позволяющие формировать двухфазное нитридное (TiN, Mo 2 N) для системы Ti–Al–Mo–N и нитридно-металлическое (TiN, Mo 2 N, Ni) для системы Ti–Al–Mo–Ni–N покрытия. Введение Ni в состав покрытия Ti–Al–Mo–N приводит к снижению среднего размера зерна нитридных фаз с 35 до 12 нм и периода модуляции с 50 до 35 нм за счет ограничения роста зародышей нитридных фаз. Одновременно с этим происходит снижение двухосных макронапряжений с σ = −2.51 ГПа для образца Ti−Al−Mo−N до σ = −0.67 ГПа для образца Ti−Al−Mo−Ni−N.

Zr-B-Si-C-Ti-N and Zr-B-Si-C-Ti coating systems were produced by arc-PVD technique. For their deposition, a combined titanium cathode with a ZrB2-SiC insert was used. Deposition was carried out in a residual atmosphere of N2 and Ar. Coatings structure and composition were investigated. The Zr-B-Si-C-Ti coating is characterized by an amorphous-nanocrystalline structure. In this case, nanocrystallites were formed from complex (Zr, Ti) C, and the amorphous structure fraction is formed mainly by phases based on zirconium and silicon. The second system, deposited in a nitrogen residual atmosphere, Zr-B-Si-C-Ti-N, has a predominantly amorphous structure. Such a structure is formed mainly from borides, nitrides, carbides and complex compounds of zirconium, silicon and titanium.

The results of studying the electrochemical behavior and thermal stability of multilayered nanostructured Ti-Al-Mo-N coatings deposited using the Arc-PVD method are reported. The paper shows that passivity of the coatings is determined by the possibility of the formation of Al2O3 layer at the interface between the aggressive environment and the coating. This effect is more marked for the coatings containing 8 at% Mo than in those containing 30 at% of Mo. It can be explained by higher mobility of Al in the coating with 8 % (at.) of Mo than in the coating with 30 % of Mo which have varied thickness of the Mo2N layer that inhibits the diffusion of Al. Investigation of thermal stability of the Ti-Al-Mo-N coatings with Mo content of 30 and 8 at% showed that their multilayered architecture are retained at temperatures up to 600 degrees C.(c) 2022 Elsevier B.V. All rights reserved.

Al 2 O 3 –TiO 2 coatings were received by flame sprayed of flexible cord and plasma sprayed using powder. Shown higher mechanical and tribological properties of flame sprayed coating compared plasma sprayed coating.

The structure and composition of multicomponent TiCrMoN-Ni arc-PVD coatings with high nickel concentration (more than 8 at.%) are studied at bias potentials of 80-140 V. All coatings are characterized by a layered structure, the modulation period tends to decrease as increasing the bias potential. After annealing at 850 °C in vacuum, the coatings retain their layered structure without signs of dissolution of layers in each other. Nickel sublayers retain their polycrystalline structure, at the same time, the monolayer CrN are formed due to recrystallization.

This article discusses methods for producing a material with gradient multilevel porosity by sintering layer-by-layer distributed α-Fe 2 O 3 nanopowders and submicron powders. Nanopowders with an average particle size of 12 nm are obtained by coprecipitation and submicron powders in the form of hollow spheres are obtained by spray pyrolysis. The powders are consolidated by sintering in a muffle furnace, by hot pressing, and by spark plasma sintering (SPS) at various temperatures, loads, and holding times. It has been demonstrated that sintering in a muffle furnace and hot pressing do not allow one to obtain a compact sample of sufficient strength due to various activity of nano- and submicron powders. SPS produced powdered materials at holding temperatures of 700, 750, 800, and 900°C in 3 min. It has been established that a series of powders produced by SPS at 750°C is characterized by sufficient strength and an open porosity of 20% upon a total porosity of 37%. An increase in temperature in the frames of SPS leads to an increase in particle size in the bulk of nanopowders to the micron range and the partial destruction of hollow submicron spheres. While studying the phase composition of the produced samples, it has been revealed that it is identical to that of the initial powders. However, in the series of samples produced by hot pressing and SPS, the growth of crystals is observed in the bulk of nanopowders in the [001] direction of the highest electric and heat conductance along the punch axes. This is related with the temperature gradient between the bulk of nanopowders and punches and the lowest surface energy of plane (110), including the [001] direction.

Arc-PVD coatings Zr-B-Si-C-Ti-N and Zr-B-Si-C-Ti were obtained using combined evaporated ZrB2-SiC-Ti cathodes in a residual atmosphere of N2 and Ar. Their structure and composition were investigated. The Zr-B-Si-C-Ti-N coating has a predominantly amorphous structure, formed mainly on the basis of nitride, carbide, boride phases and complex compounds Zr, Si, Ti. The Zr-B-Si-C-Ti coating is characterized by an amorphous-nanocrystalline structure. The amorphous component of this coating is formed mainly by phases based on Zr and Si. The nanocrystalline structure is formed by a complex carbide (Zr, Ti) C.