Alexander Pogrebnjak

• Doctor of Sciences, Professor
• Sumy State University

The dependence of polyethylene deformation on applied mechanical stress under varying load conditions and radiation doses was investigated experimentally. Obtained results reveal significant alterations in the mechanical properties of polyethylene following irradiation with krypton ions at doses of 1.5 × 10⁶, 1.6 × 10⁷, 5.0 × 10⁸, and 1.0 × 10⁹ ion...

Hard nitride coatings have the potential to serve as protective layers for cutting tools due to their excellent mechanical properties and wear resistance. To improve their mechanical, tribological, and high-temperature oxidation characteristics, the structural design of the coating is crucial. This study explores the micromechanical and tribologica...

Protection against microbiologically influenced corrosion (MIC) is critical for materials used in aquatic environments, as MIC accelerates material degradation and leads to faster structural failure. Copper (Cu) has the potential to substantially improve the MIC resistance in alloys. In this study, high-entropy alloy (HEA) coatings containing Cu we...

TiZrMoC coatings were deposited on Si(100) substrates using a DC dual magnetron sputtering. The composition was controlled by adjusting the sputtering parameters of the TiZrMo and graphite targets. The influence of graphite target current on the resulting coating properties was explored. TEM analysis revealed a single-phase structure with Ti/Mo/Zr...

The rapid development of industrial applications places severe demands on the mechanical properties of protective coatings. Unraveling the hardening mechanism and deformation behavior is essential for the design of advanced hard coatings. In this paper, a novel AlCrNbSiTiN high-entropy nitride (HEN) coating with an extremely low wear rate of 6.3 ×...

LiNbO3 films doped with vanadium (V) were deposited using RF magnetron sputtering technique. To realize doping with a wider range of V concentration, a 30 mm V metal inlaid target asymmetrically embedded in the 150 mm lithium niobate target was used. The V concentration in the deposited films was a decreasing function of the distance from the V tar...

In this study, in order to determine the effect of matrices’ shape on the percolation threshold values, computer simulations were performed using the Monte Carlo method for a 200 × 200 square-shaped matrix and rectangular matrices containing the same number of nodes as the square matrix. Based on the simulations, the average values of the percolati...

In this work, the adhesive and tribological characteristics of (TiZrNbYAl)N multilayer coatings were studied. The main goal of this work is to assess the influence of the number of layers on the adhesive and tribological characteristics of the (TiZrNbYAl)N coating deposited on 12Х18Н9Т steel substrates. A study of the distribution of elements over...

In this study, in order to determine the effect of matrices shape on percolation threshold values, computer simulations were performed using the Monte Carlo method for a 200x200 square-shaped matrix and rectangular matrices containing the same number of nodes as the square matrix. Based on the simulations, the average values of percolation threshol...

For decades, conventional alloys represented the main pillar of engineering applications. However, their performances reach the limit when it faces tough demanding environments. High-entropy alloys (HEAs) meet this important challenge by leveraging the concept of entropy to achieve a unique combination of properties. This scientific paper presents...

High-Entropy Alloys (HEAs) represent a transformative class of materials characterized by multiple principal elements and high configurational entropy. This review article provides an in-depth examination of their structural particularities, prediction methodologies, and synthesis techniques. HEAs exhibit unique structural stability due to high-ent...

In the original publication [...]

This study investigates the phase composition, microstructure, and their influence on the properties of Mo-W-C nanocomposite films deposited by dual-source magnetron sputtering. The synthesised films consist of metal carbide nanograins embedded in an amorphous carbon matrix. It has been found that nanograins are composed of the hexagonal β-(Mo2 + W...

Hard nitride coatings are commonly employed to protect components subjected to friction, whereby such coatings should possess excellent tribomechanical properties in order to endure high stresses and temperatures. In this study, WN/NbN coatings are synthesized by using the cathodic-arc evaporation (CA-PVD) technique at various negative bias voltage...

LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> thin film ultrasonic transducers were deposited using RF magnetron sputtering technique. Optimization of the sample position in the deposition chamber and deposition parameters was carried out to obtain the strongest pulse-echo response of L...

In this work, WN/NbN nanolaminate coatings were synthesized by cathodic-arc physical vapor deposition (CA-PVD) technique on a stainless-steel substrate. The paper reports the microstructure, cross-sectional morphology, surface roughness, and adhesion strength changes caused by variations in the absolute values of the negative substrate bias voltage...

Effective cardiac tissue regeneration necessitates scaffolds that mimic the native extracellular matrix and possess desirable properties, such as electrical conductivity and biocompatibility. The choice of an appropriate fabrication method is paramount in achieving reproducibility, scalability, and rapid production of cardiac tissue patches. Electr...

In this study, an in-depth analysis of the percolation phenomenon for square matrices with dimensions from L = 50 to 600 for a sample number of 5 × 10⁴ was performed using Monte Carlo computer simulations. The percolation threshold value was defined as the number of conductive nodes remaining in the matrix before drawing the node interrupting the l...

MXene exhibits impressive characteristics, including flexibility, mechanical robustness, the capacity to cleanse liquids like water through MXene membranes, water-attracting nature, and effectiveness against bacteria. Additionally, bacterial cellulose (BC) exhibits remarkable qualities, including mechanical strength, water absorption, porosity, and...

New conductive materials for tissue engineering are needed for the development of regenerative strategies for nervous, muscular, and heart tissues. Polycaprolactone (PCL) is used to obtain biocompatible and biodegradable nanofiber scaffolds by electrospinning. MXenes, a large class of biocompatible 2D nanomaterials, can make polymer scaffolds condu...

The films of the Ti-Nb-C system were deposited by direct current (DC) magnetron co-sputtering of composite Ti+Nb, and graphite targets onto Si substrates to which negative substrate bias in the range of -50÷-200 V was applied during film deposition. The microstructure, chemical bonds, and mechanical properties of films were comparatively investigat...

The present work deals with the comparison of selected properties of WN x /TiSiN multilayer and respective WN x and TiSiN monolithic coatings that were deposited at the same parameters. The effect of the multilayer architecture on the structure and mechanical properties of WN x /TiSiN multilayer was studied in detail. The multilayers and monolayers...

In this paper, the frequency-temperature dependence of the conductivity and dielectric permittivity of nc-TixZr1−xC+α-Cy (0.0 ≤ x ≤ 1.0) nanocomposites produced by dual-source magnetron sputtering was determined. The films produced are biphasic layers with an excess of amorphous carbon relative to the stoichiometric composition of TixZr1−xC. The ma...

In the present work, we studied structure, surface morphology, and ultrasonic response of thin film Lithium Niobium Oxide (LNO) transducers deposited on Inconel bolts, stainless steel and silicon substrates by radio frequency magnetron sputtering. The deposited transducer material was a mixture of LiNbO3/LiNb3O8 phases, having a well-developed colu...

Bacterial cellulose (BC) is a biopolymer produced by different microorganisms, but in biotechnological practice, Komagataeibacter xylinus is used. The micro- and nanofibrillar structure of BC, which forms many different-sized pores, creates prerequisites for the introduction of other polymers into it, including those synthesized by other microorgan...

This article shows the results of a study on a biocomposite material based on calcium phosphate doped with ZnCl and AgNO3 . Calcium phosphates are mainly used in dentistry and orthopedics due to their excellent biocompatibility, osteoconductive properties and similarity to the inorganic components of human bone. The main objective of the study is t...

Innovative therapies are urgently needed to combat cancer. Thermal ablation of tumor cells is a promising minimally invasive treatment option. Infrared light can penetrate human tissues and reach superficial malignancies. MXenes are a class of 2D materials that consist of carbides/nitrides of transition metals. The transverse surface plasmons of MX...

In this study, the conductivity and permittivity of electrical pressboard—insulating liquid—water composites were investigated, and the electrical properties of the composites and water were analysed comparatively. Mineral oil and synthetic ester were used as insulating liquids. It was found that the presence of water caused an increase in the perm...

Nanocomposite multilayer coatings are of large interest to the engineering industry because of their functional properties. Titanium nitride-based multilayer structures are very effective as protective layers for mechanical instrumentation. In this paper, selected mechanical and tribological properties for cutting machinery of TiASiYN/CrN system we...

Composite Ti3SiC2/TiC MAX-phase coating was obtained by the detonation spraying onto U9 steel substrate using the mixed powder in the molar ratio of 74Ti/20SiC/6C as raw material. At the as-sprayed state, the synthesized composite had a stable double-phase composition: the main TiC phase and secondary Ti3SiC2 MAX-phase. After thermal annealing at 7...

The diffusion of substrate material into absorbing layer and oxidation of metal substrate or cermet metal nanoparticles at high temperatures are known as inevitable problems of the solar selective absorbers. In this study, we consider the use of textured stainless steel (SS) surface coated with a protective AlCr oxide layer as a high temperature so...

Due to the increased demands for drilling and cutting tools working at extreme machining conditions, protective coatings are extensively utilized to prolong the tool life and eliminate the need for lubricants. The present work reports on the effect of a second MeN (Me = Zr, Cr, Mo, Nb) layer in WN-based nanocomposite multilayers on microstructure,...

A new class of two-dimensional nanomaterials, MXenes, which are carbides/nitrides/carbonitrides of transition and refractory metals, has been critically analyzed. Since the synthesis of the first family member in 2011 by Yury Gogotsi and colleagues, MXenes have quickly become attractive for a variety of research fields due to their exceptional prop...

The diffusion of substrate material into absorbing layer and oxidation of metal substrate or cermet metal nanoparticles at high temperatures are known as inevitable problems of the solar selective absorbers. In this study, we consider the use of textured stainless steel (SS) surface coated with a protective AlCr oxide layer as a high temperature so...

Monolayer tungsten nitride (WN) and multilayer WN/titanium nitride (TiN) and WN/titanium silicon nitride [(TiSi)N] coatings were produced by vacuum arc deposition on a Bulat-6 setup with continuous rotation of the substrate and samples. The results of the phase identification showed that the monolayer WN coating consisted of a cubic WN-β phase, whi...

The influence of silver ions on antibacterial properties and morphology of Hydroxyapatite-Ag (HА-Ag) and Hydroxyapatite-Alginate-Ag (HA-Alg-Ag) nanocomposites was studied. The microstructure and phase composition of the obtained nanocomposites were investigated by SEM, TEM, XRD, FTIR methods, and the formation of the crystalline phase of Ag 3 PO 4...

The paper examined Ti3C2Tx MXene (T—OH, Cl or F), which is prepared by etching a layered ternary carbide Ti3AlC2 (312 MAX-phase) precursor and deposited on a polycaprolactone (PCL) electrospun membrane (MXene-PCL nanocomposite). X-ray Diffraction analysis (XRD) and Scanning Electron Microscopy (SEM) indicates that the obtained material is pure Ti3C...

The ability to combine layers with high mechanical strength and additional physicochemical properties, such as biocompatibility, makes the use of multilayer coatings attractive for various applications. The transition from single layer to nanolaminate architecture can improve the mechanical performance of the coatings by increasing the number of in...

Nanoscale multilayer TiSiN/NbN coatings with a modulation period ranging from 75 to 50 nm were deposited onto steel using the cathodic arc physical vapor deposition technique. The microstructure of multilayer TiSiN/NbN coatings was nanocomposite consisting of nanocrystallite phases fcc-TiN and hcp- NbN-δ'. With the increase of the bias potential fr...

A study of defect structure in (TiZrHfNbV)N coatings irradiated with 200 MeV high energy Xe¹⁴⁺ ions with different fluences by positron annihilation spectroscopy (PAS) was carried out. Positron lifetime studies showed that the vacancy-defects are the dominant defects type in investigated specimens. Although (TiZrHfNbV)N coatings were irradiated wit...

The paper describes mechanical, electrical and chemical properties of modified polycarbonate obtained by hot compression moulding of core-shell composites consisting of a polymer core covered with a shell containing single-walled carbon nanotubes (SWCNTs). Such an approach in material design based on an ultralow modification with nanomaterials allo...

A combination of coating deposition and consequent ion implantation could be beneficial in wear-resistant antifriction surface design and modification. In the present paper, the effects of low-energy 60 keV Si-ion implantation on multinanolayered CrN/ZrN grown on a stainless-steel substrate have been investigated. Complementary experimental (X-ray...

Multilayer TiZrN/TiSiN coatings were deposited on steel substrate by the cathodic-arc evaporation technique. The TiZr (75:25 at. %) and TiSi (95:5 at. %) alloy cathodes served as evaporation sources. Scanning electron microscopy with energy-dispersive spectroscopy, secondary ion mass-spectrometry, X-ray diffraction and X-ray photoelectron spectrosc...

Nanocomposites based on hard compounds are currently on the stage of active research and development. Hence the analysis of a relation between nanostructure and functional properties are of great importance. The main purpose of the study was to assess the stoichiometry effect on the finite characteristics of TiZrC nanocomposite coatings. This paper...

Aerospace is an actively developing industry that continuously requires the implementation of modern technologies. The rapid growth in new vehicle production demands much support. Hence, the problem of resources with complicated supply and distribution is always of current interest. These critical raw materials (CRMs) are involved in almost all are...

Triply periodic minimal surfaces (TPMS) are known for their advanced mechanical properties and are wrinkle-free with a smooth local topology. These surfaces provide suitable conditions for cell attachment and proliferation. In this study, the in vitro osteoinductive and antibacterial properties of scaffolds with different minimal pore diameters and...

Current trends in and problems facing the development of the scanning nuclear microprobe are reviewed. The application of slow positrons to diagnosing materials is examined and the techniques of positron microscopy and microprobing are presented. The potential of near-field microwave microscopy for diagnosing superconducting ceramics and of microwa...

This paper introduces the theoretical and experimental investigation of multilayer (TiAlSiY)N/CrN coating deposited on a steel substrate using the cathodic-arc evaporation technique. The firstprinciples calculations show that the deposition of Ti1–xAlxN/CrN nanolayer with high Alx content (x = 0.75) has a severe stabilization effect that certainly...

The findings of the last years regarding the deep and machine learning algorithms provided the substantial impetus to the discovery of heretofore unknown data. The future of mechanical/electromechanical engineering lies in the design of smart materials and technologies. In this paper, the problem of material design in particular for applications in...

A series of nanolaminate (Al50Ti50)N/ZrN coatings with different modulation period (λ) and bias voltage were synthesized by vacuum arc deposition (VA-PVD). The composition, evolution of the microstructure, and mechanical properties were studied during the transition from the basic monolayer (Al50Ti50)N coating to the nanolaminate architecture with...

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In order to obtain the modified surface structure of the 20Cr2Ni4A steel plasma electrolytic hardening (PEH) method was used. The surface hardening process was conducted in the aqueous electrolyte solution of 20% sodium carbonate and 20% urea. The sample consists of a ferritic-pearlitic structure, i.e. the part retains its viscous core, and the sur...

The composite materials based on hydroxyapatite (HA), sodium alginate (Alg)–magnetite (Fe3O4) were synthesized by the “wet chemistry method” under the influence of microwave irradiation and ultrasound. The biomagnetic samples were investigated by XRD, RFA, SEM, TEM and colorimetric assay methods. The cytotoxicity was assessed on fibroblasts culture...

The novel nanocomposite Ti-Si-La-N coatings were deposited using the cathodic arc evaporation process. The effect of different lanthanum contents (0 - 13 at.%) on the chemical composition, structural evolution, and mechanical properties of nanocomposites was studied. Analysis of structure showed that all Ti-Si-La-N series consisted of a crystalline...

Fabrication and development of HfB2-based nanostructured coatings was investigated. All films were deposited on stainless-steel substrates by RF magnetron sputtering from stochiometric HfB2 target in argon atmosphere. The aim of this work is to evaluate the effects of the bias potential on the microstructure, mechanical and tribological properties....

Open Access Link (by 10th of May 2020): https://authors.elsevier.com/a/1amRj3IWkc0GAX The main principles of formation of microstructure and properties of the nanostructured films consisting of periodically alternating multilayers of CrN/ZrN transition metal nitride films and Cr/Zr pure metals were investigated. First-principles calculations were c...

This book covers novel and innovative technologies used in development, modeling, chemical/physical investigation and biomedical (in-vitro and in-vivo) trials of nanomaterials and nanocomposites. Novel methods for nanoparticle development and manufacturing are presented, as well as their safety and promising applications. In addition, the book high...

As result of plasma-electrolytic nitrocarburizing 30CrMnSiA carbon steel (ferrite-perlite grade), there was a change in the elemental and phase composition, as well as the surface layer microstructure (40 ÷ 45 microns thick from the surface). A formation of Me23(CN)6 carbonitrides, FeN nitrides, Fe3C - (Fe,Cr)3C carbides and an increase in dislocat...

The paper presents the results of studies of biocompatibility and antibacterial properties of multiphase nanocomposite materials based on HA-Alg-ZnO (hydroxyapatite‑sodium alginate-biphasic zinc oxide) and HA-ZnO (hydroxyapatite‑zinc oxide), which were synthesized from the analytically pure calcium nitrate tetrahydrate, ammonium hydrophosphate, hyd...