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Ситников, Николай Николаевич

Организационные подразделения

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Институт лазерных и плазменных технологий

Стратегическая цель Института ЛаПлаз – стать ведущей научной школой и ядром развития инноваций по лазерным, плазменным, радиационным и ускорительным технологиям, с уникальными образовательными программами, востребованными на российском и мировом рынке образовательных услуг.

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Николай Николаевич

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Только метаданные
Investigation of wear dynamics for cutting tools with multilayer composite nanostructured coatings in turning constructional steel
(2019) Vereschaka, A.; Tabakov, V.; Grigoriev, S.; Oganyan, G.; Sitnikov, N.; Ситников, Николай Николаевич
© 2018 Elsevier B.V. The paper deals with the wear dynamics shown by carbide tools with multilayer composite nanostructured coatings of various compositions. The investigation involved coatings based on nitrides of such metals as Ti, Zr, Cr, Nb, and Al with three-layer architecture, including adhesion, transition, and wear-resistant layers. The thickness of the coatings was about 4 µm. There was a series of cutting tests involving tools with the coatings under study in the turning of AISI 1045 steel at vc = 200, 250, 300, and 350 m/min. The comparative studies were conducted to investigate wear process patterns for tools with the coatings under study and for uncoated tools and tools with TiN reference coatings, depending on the cutting speed. In particular, the study considered the intensity and specific features of crater formation on the tool rake face. In particular, it was found that an increase in cutting speed led to more active movement of a crater away from the cutting edge, while at lower cutting speeds, a crater developed evenly. Diffusion and oxidation processes were registered and studied at the boundary between the coating and the material being machined. The use of the coatings under study makes it possible to significantly increase the cutting speed, while the optimal composition of the coating depends on the applied cutting speed.
Только метаданные
Investigation of the influence of the thickness of nanolayers in wear-resistant layers of Ti-TiN-(Ti,Cr,Al)N coating on destruction in the cutting and wear of carbide cutting tools
(2020) Vereschaka, A.; Tabakov, V.; Grigoriev, S.; Milovich, F.; Sitnikov, N.; Ситников, Николай Николаевич
© 2020 Elsevier B.V.The paper presents the results of the investigation into the formation of the nanolayer structure of the Ti-TiN-(Ti,Cr,Al)N coating and its influence on the thickness of coatings, their resistance to fracture in scratch testing, and the wear resistance of coated tools in turning 1045 steel. The structure of the coatings with the nanolayer thicknesses of 302, 160, 70, 53, 38, 24, 16, and 10 nm was studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution (HR) TEM. It is shown that the grain sizes in the nanolayers decrease to certain values with an increase in the thickness of the nanolayers, and then, with a further decrease in the nanolayer thickness, the grain sizes of the nanolayer grow as the interlayer interfaces cease to produce a restraining effect on the growth of the grains. The study found that the nanolayer thickness influenced the wear of carbide cutting tools and the pattern of fracture for the Ti-TiN-(Ti,Cr,Al)N coatings.
Только метаданные
Investigation of multicomponent nanolayer coatings based on nitrides of Cr, Mo, Zr, Nb, and Al
(2020) Grigoriev, S.; Vereschaka, A.; Milovich, F.; Tabakov, V.; Sitnikov, N.; Ситников, Николай Николаевич
© 2020 Elsevier B.V.This paper presents the results of the investigations of multicomponent nanolayer coatings of Cr,Mo-(Cr,Mo,Zr,Nb)N-(Cr,Mo,Zr,Nb,Al)N, Cr,Mo-(Cr,Mo)N-(Cr,Mo,Al)N, and Zr,Nb-(Zr,Nb)N-(Zr,Nb,Al)N. The data on the microstructures and nanostructures of the coatings, including the hardness, phase composition, and chemical composition by coating thickness are presented. The research considers the differences in the phase composition of the coatings and reveals the difference in the wear process on the contact pads of the carbide inserts between the studied coatings and the wear patterns on the coatings from cutting workpieces made of 1045 steel. The multicomponent Cr,Mo-(Cr,Mo)N-(Cr,Mo,Zr,Nb,Al)N coating contains two cubic phases of (Cr,Mo,Al)N and (Zr,Nb,Al)N with the space group Fm3¯m. The Cr,Mo-(Cr,Mo)N-(Cr,Mo,Zr,Nb,Al)N coating exhibited the maximum hardness among the studied coatings, and a tool with such a coating demonstrated the longest lifetime. The coating is also characterized by higher resistance to brittle fracture and cracking.
Только метаданные
Investigation of wear mechanisms for the rake face of a cutting tool with a multilayer composite nanostructured Cr–CrN-(Ti,Cr,Al,Si)N coating in high-speed steel turning
(2019) Vereschaka, A.; Tabakov, V.; Grigoriev, S.; Milovich, F.; Sitnikov, N.; Ситников, Николай Николаевич
© 2019 Elsevier B.V.The article considers the wear pattern for the rake face of a cutting tool with the Cr–CrN-(Ti,Cr,Al,Si)N multilayer composite nanostructured coating in turning 1045 steel at vc = 300 m/min. Attention was paid to the diffusion and oxidation processes and effect of high temperature because these wear factors prevailed at high cutting speeds. Studies were conducted using a high-resolution transmission electron microscope and energy-dispersive X-ray spectroscopy. The study of the wear-crater boundary area revealed a layer with lost nanostructure (destruction layer) in the outer coating area. The thickness of the layer was 100–700 nm, depending on its location relative to the wear crater. The layer, which was formed under simultaneous exposure to high temperatures and diffusion and oxidation processes, was characterized by variable thickness and chemical composition, depending on its location relative to the wear crater. In particular, there are large volumes of oxygen in areas with freer access to air, while the oxygen content is significantly lower in the area of the bridge between the wear crater and cutting edge. The Al content increased significantly as the layer approached the cutting-edge area due to an increase in temperature and intensification of the spinodal decomposition process.
Только метаданные
Effect of temperature and oxidation in cutting zone on wear of cutting tools with multilayer composite nano-structured coatings at high speed turning
(2019) Volosova, M.; Vereschaka, A.; Okunkova, A.; Andreev, N.; Sitnikov, N.; Ситников, Николай Николаевич
© 2019, MM publishing Ltd.. All rights reserved.The article discusses the ability of multilayer composite nano-structured coatings based on the Cr-CrN-(Ti,Cr,Al,Si)N system to resist wear factors activated with increasing temperature, such as diffusion and oxidation processes, as well as spinodal decomposition of the coating material. Investigators were carried out in turning C45 steel at the following cutting conditions: f = 0.2 mm/rev, ap = 1.0 mm, vc = 300 m/min. SEM and TEM techniques were used to investigate changes in nano-structures of coatings, as well as diffusion and oxidation processes. Of particular interest was the study of a layer of nanometric thickness on the rake surface of the tool, between the adhered material being machined and the surface nanolayers of the coating. The content of oxygen, iron, and metals the coating was investigated. A lot significant difference was revealed in the content of elements in the layer investigated, depending on the location of the area studied around a crater on the rake face of the tool.
Только метаданные
Specifics in formation of nanolayer structure of coatings during their deposition using filtered cathodic vacuum arc deposition (FCVAD) technology
(2019) Vereschaka, A.; Sitnikov, N.; Oganyan, G.; Sotova, C.; Ситников, Николай Николаевич
The paper discusses the specific features of the formation of nanolayer structures of modifying coatings for metal-cutting tools using FCVAD technology. It is found that the nanolayer coating structure is affected both by the rotation speed of the turntable and by the speed of the planetary rotation of the tool set. It is found that the coating with the minimum thicknesses of nanolayers (about 4-6 nm) provides the longest tool life period. (C) 2019 Elsevier Ltd. All rights reserved.
Только метаданные
Investigation of tribological and functional properties of Cr,Mo-(Cr,Mo)N-(Cr,Mo,Al)N multilayer composite coating
(2021) Vereschaka, A.; Grigoriev, S.; Milovich, F.; Migranov, M.; Sitnikov, N.; Ситников, Николай Николаевич
© 2020 Elsevier LtdThe article describes the investigation of the properties of the Cr,Mo-(Cr,Mo)N-(Cr,Mo,Al)N multilayer composite coating. For the coated sample, the adhesion component fadh of the coefficient of friction increases almost linearly with an increase in temperature from 500 to 700 °C. Then, with a further rise in temperature up to 800 °C, the growth of fadh slows down significantly, and when the temperature rises from 800 to 1000 °C, fadh begins to decrease noticeably. The studies deal with the cutting properties of carbide tools with the coating under study during the cutting of corrosion-resistant AISI 321 at various cutting speeds. The wear pattern on the coating during the cutting was considered. An diffusion layer with the thickness of 20–40 nm was detected during the studies of the elemental and phase compositions in the region of the “tool material–coating” interface. In this layer, the studies revealed the active diffusion of Fe and other steel components into the coating, as well as the diffusion of Mo from the coating into the material being machined in combination with oxidation processes. It was found that during the cutting with the coated tool, the thickness of the diffusion layer was 10–15 times lower compared to that in the uncoated tool. While a certain content of oxygen is detected in the layers on the coating surface, no active formation of the oxides of Al2O3, MoO3, and Cr2O3 was revealed, and the formation of a noticeable amount of Fe2O3 was found in the layers of the material being machined adjacent to the coating surface.
Только метаданные
Investigation of the properties of the Cr,Mo-(Cr,Mo,Zr,Nb)N-(Cr,Mo,Zr,Nb,Al)N multilayer composite multicomponent coating with nanostructured wear-resistant layer
(2021) Grigoriev, S.; Vereschaka, A.; Milovich, F.; Andreev, N.; Sitnikov, N.; Ситников, Николай Николаевич
© 2020 Elsevier B.V.The article discusses the properties of the Cr,Mo-(Cr,Mo,Zr,Nb)N-(Cr,Mo,Zr,Nb,Al)N multilayer composite multicomponent coating with a nanostructured wear-resistant layer. The structure and phase composition of the coating were investigated. The comparative cutting tests were carried out on carbide cutting tools with the coating under study and carbide cutting tools with the Ti–TiN-(Ti,Al,Cr)N commercial coating. Particular attention was paid to the study of the wear and fracture patterns typical for the coating and the diffusion processes on the “coating–material being machined” interface. The studies found the difference in the content of Fe in the coating nanolayers. In particular, the high content of Fe was detected in the nanolayers with the increased content of Cr–Mo, while the nanolayers with the increased content of Al demonstrated the low content of Fe. The depth of the Fe diffusion into the coating is 2–3 times lower compared to the Fe diffusion into a carbide substrate. The influence of the nanolayer structure of the coating on the crack propagation was considered. The studies revealed signs of plastic deformation in the surface layers of the coating. The investigation was also focused on the structure of a build-up of the material being machined with a layer structure demonstrating different levels of the oxidation inits layers.
Только метаданные
Application of nanostructured Zr-ZrN-(Zr,Al)N and Zr-ZrN-(Zr,Cr,Al)N coatings for improvement of tool life and performance in end milling of carbides
(2019) Vereschaka, A.; Oganyan, M.; Bublikov, Y.; Deev, K.; Sitnikov, N.; Ситников, Николай Николаевич
© 2019 IOP Publishing Ltd. All rights reserved.The paper deals with the challenges of improving the tool life of end mills and performance in end milling of carbides through application of tools with the nanostructured Zr-ZrN-(Zr,Al)N and Zr-ZrN-(Zr,Cr,Al)N coatings, deposited using the filtered cathodic vacuum arc deposition (FCVAD) technology. The main mechanical characteristics of the above coatings (microhardness and critical fracture load) were determined. The cutting properties were investigated at mill rotation frequency of n = 1250, 1600, 2000 rpm. Samples were compared with uncoated tools and with tools with commercial coatings, including monolayer Ti-TiN and nanostructured Ti-TiN-(Ti,Al)N coatings. The studies have proved that the proposed coatings are not only able to improve the tool life, but they also allow milling at higher mill rotation frequency, and, consequently, with higher performance of milling. Meanwhile, tools with the Zr-ZrN-(Zr,Al)N and Zr-ZrN-(Zr,Cr,Al)N coatings are characterized by more balanced pattern of wear, without visible signs of brittle fracture.
Только метаданные
Effect of adhesion and the wear-resistant layer thickness ratio on mechanical and performance properties of ZrN - (Zr,Al,Si)N coatings
(2019) Vereschaka, A.; Tabakov, V.; Grigoriev, S.; Aksenenko, A.; Sitnikov, N.; Ситников, Николай Николаевич
© 2018 Elsevier B.V. The study involved the investigation of the effect of the thickness of the adhesion layers (0.3 and 0.7 μm) and the wear-resistant layer (2.0, 4.0, 6.0, and 8.0 μm) on the microhardness, adhesion bond strength, and performance properties of the ZrN-(Zr,Al,Si)N coatings. The scratch-test method was applied to study the adhesion bond strength to the substrate and coating failure patterns. The study revealed an effect of the coefficient kwa, determining the effect of the thicknesses of the wear-resistant and adhesion layers of the coating on the value of the critical load LC2. The study investigated the wear patterns and mechanisms for the specified coatings and the tool life of tools with these coatings in turning. An effect of the coefficient kwa which is the adhesion and wear-resistant layer thickness ratio on the tool life and a difference in the wear pattern dynamics for tools with these coatings with wear-resistant layers of equal thickness and adhesion layers of different thicknesses was revealed. The study also determined the chemical and phase composition of the coatings.