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311 results on '"Pogrebnjak, Alexander"'

2. Novel electrically conductive electrospun PCL-MXene scaffolds for cardiac tissue regeneration

Author

Diedkova, Kateryna, Husak, Yevheniia, Simka, Wojciech, Korniienko, Viktoriia, Petrovic, Bojan, Roshchupkin, Anton, Stolarczyk, Agnieszka, Waloszczyk, Natalia, Yanko, Ilya, Jekabsons, Kaspars, Čaplovičová, Maria, Pogrebnjak, Alexander D., Zahorodna, Veronika, Gogotsi, Oleksiy, Roslyk, Iryna, Baginskiy, Ivan, Radovic, Marko, Kojic, Sanja, Riekstina, Una, and Pogorielov, Maksym

Published
2024
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3. AlCrO protected textured stainless steel surface for high temperature solar selective absorber applications

Author

Pelenovich, Vasiliy, Zeng, Xiaomei, Liu, Yan, Zhang, Xiangyu, Liu, Huidong, Pogrebnjak, Alexander, Vildanov, Ramil', Yang, Bing, and Liu, Sheng

Subjects
Physics - Chemical Physics, Condensed Matter - Materials Science
Abstract

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 solar selective absorber. The textured SS surface was prepared by ion etching techniques and AlCr oxide protective layer was deposited by RF magnetron sputtering. The absorptivity and emissivity of the as-prepared absorbers were 0.86-0.92 and 0.151-0.168, respectively. In order to evaluate the thermal stability, the absorbers were annealed at 600-800 C for different time in ambient atmosphere. Absorbers demonstrated a red shift of the onset of the reflectivity at all annealing temperatures. The high activation energy of 315 kJ/mol was calculated. The service lifetime of the absorbers at 500 C was estimated to be about 100 years and at 700 and 800 C the absorbers were stable about 50 and 1 hours, respectively. A detailed examination of the annealed absorber surface revealed growth of surface Mn3O4 nanocrystals, which resulted in observed change of the reflectance spectra, while the textured surface morphology had no significant change. The results show that the protective textured surface has much higher thermal stability in air than iron based cermet absorbers., Comment: 10 pages, 6 figures

Published
2021
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14. Microstructural, Electrical, and Tribomechanical Properties of Mo-W-C Nanocomposite Films.

Author

Smyrnova, Kateryna, Ivashchenko, Volodymyr I., Sahul, Martin, Čaplovič, Ľubomír, Skrynskyi, Petro, Kozak, Andrii, Konarski, Piotr, Koltunowicz, Tomasz N., Galaszkiewicz, Piotr, Bondariev, Vitalii, Zukowski, Pawel, Budzynski, Piotr, Borba-Pogrebnjak, Svitlana, Kamiński, Mariusz, Bónová, Lucia, Beresnev, Vyacheslav, and Pogrebnjak, Alexander

Subjects
NANOCOMPOSITE materials, MICROELECTROMECHANICAL systems, MAGNETRON sputtering, AMORPHOUS carbon, POWER electronics, TUNGSTEN alloys
Abstract

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 + W2)C phase at a low carbon source power. An increase in the power results in the change in the structure of the carbide nanoparticles from a single-phase to a mixture of the β-(Mo2 + W2)C and NaCl-type α-(Mo + W)C(0.65≤k≤1) solid-solution phases. The analysis of electrical properties demonstrates that the nanograin structure of the films favours the occurrence of hopping conductivity. The double-phase structure leads to a twofold increase in the relaxation time compared to the single-phase one. Films with both types of nanograin structures exhibit tunnelling conductance without the need for thermal activation. The average distance between the potential wells produced by the carbide nanograins in nanocomposite films is approximately 3.4 ± 0.2 nm. A study of tribomechanical properties showed that Mo-W-C films composed of a mixture of the β-(Mo2 + W2)C and α-(Mo + W)C(0.65≤k≤1) phases have the highest hardness (19–22 GPa) and the lowest friction coefficient (0.15–0.24) and wear volume (0.00302–0.00381 mm2). Such a combination of electrical and tribomechanical properties demonstrates the suitability of Mo-W-C nanocomposite films for various micromechanical devices and power electronics. [ABSTRACT FROM AUTHOR]

Published
2024
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19. Impact of Multilayer Architecture on the Tribological Behaviour of Wnx/Tisin Coating Versus Monolithic Wnx and Tisin Layers

Author

Smyrnova, Kateryna, primary, Sahul, Martin, additional, Bočáková, Barbora, additional, Haršáni, Marián, additional, Truchlý, Martin, additional, Sahul, Miroslav, additional, Vopát, Tomáš, additional, Pašák, Matej, additional, Maksakova, Olga, additional, Škrobáková, Ivana, additional, Čaplovič, Ľubomír, additional, and Pogrebnjak, Alexander, additional

Published
2024
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23. Machine Learning-Based Design of Superhard High-Entropy Nitride Coatings

Author

Zhang, Xiangyu, Jia, Binyuan, Zeng, Zhong, Zeng, Xiaomei, Wan, Qiang, Pogrebnjak, Alexander, Zhang, Jun, Pelenovich, Vasiliy, and Yang, Bing

Abstract

Limited by the inefficiency of the conventional trial-and-error method and the boundless compositional design space of high-entropy alloys (HEAs), accelerating the discovery of superior-performing high-entropy nitride (HEN) coatings remains a formidable challenge. Herein, the superhard HEN coatings were designed and prepared using the rapidly developing data-driven model machine learning (ML). A database containing hardness and different features of HEN coatings was established and categorized into four subsets covering the information on composition, composition–physical descriptors, composition–technique parameters, and composition–physical descriptors–technique parameters. Feature engineering was employed to reduce dimensionality and interpret the impact of features on the evolution of hardness. Both root mean squared error (RMSE) and decision coefficient (R2) were applied to assess the predictive accuracy of ML models with different subsets, proportions of test set, and algorithms. The model with best predicted performance was used to explore superhard HEN coatings in a predefined virtual space. Among the generated 5-/6-/7-/8-component (excluding N) systems, the coating possessing highest hardness was individually selected for further preparation. Four newly prepared coatings achieved the superhard level with an average prediction error of 7.83%. The morphology, chemical composition, structure, and hardness of the newly prepared coatings were discussed. The nanocrystal–amorphous nanocomposite structure of the novel AlCrNbSiTiN coating with the highest hardness of 45.77 GPa was revealed. The results demonstrated that ML can effectively guide the design and composition optimization of superb-performance protective HEN coatings.

Published
2024
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24. Effect of Bilayer Thickness and Bias Potential on the Structure and Properties of (TiZr/Nb)N Multilayer Coatings as a Result of Arc-PVD Deposition

Author

Rakhadilov Bauyrzhan, Pogrebnjak Alexander, Sagdoldina Zhuldyz, Buitkenov Dastan, Beresnev Vyacheslav, and Amina Mukhamedova

Subjects
multilayer coating, Arc-PVD, (TiZr/Nb)N, phase, wear resistance, hardness, Technology, Electrical engineering. Electronics. Nuclear engineering, TK1-9971, Engineering (General). Civil engineering (General), TA1-2040, Microscopy, QH201-278.5, Descriptive and experimental mechanics, QC120-168.85
Abstract

This work is devoted to the study of the formation of nanostructured multilayer coatings (TiZr/Nb)N on the surface of an AISI 321 steel substrate depending on the deposition parameters of the Arc-PVD method. The results of the X-ray diffraction analysis showed the formation of solid solution (TiNb)N and ZrN in the multilayer coatings with an FCC structure, ε-NbN with a hexagonal structure, as well as with a small volume fraction of the ε-Ti2N and β-Nb2N phase. On the basis of phase composition data, it is possible to assume that an increase in the number of bilayers leads to a decrease in the nitrogen concentration in the bilayers and, consequently, to a decrease in the volume fraction of ε-NbN and β-Nb2N nitrides. In all investigated systems obtained at −100 V and −200 V bias potentials, ε-NbN is the main phase. The study of the element distribution over the thickness of the (TiZr/Nb)N coating confirms the results of the X-ray diffraction analysis. The use of the structure model in the form of alternating layers allows for significantly improving the adhesion characteristics of the protective coating, as well as ensuring their high hardness. Based on the experimental results, it is possible to analyze changes in the mechanical and tribological properties of multilayer coatings depending on the number of applied bilayers. The results of the study of the elastic modulus and hardness of multilayer coatings (TiZrNb)N with different numbers of bilayers showed that a large number of bilayers (small thickness of each individual layer) shows the lowest value of hardness. It is assumed that as the bilayer thickness decreases, the coating characteristics are closer to the monolayer alloy than to the multilayer structure.

Published
2022
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31. Polycaprolactone–MXene Nanofibrous Scaffolds for Tissue Engineering

Author

Diedkova, Kateryna, primary, Pogrebnjak, Alexander D., additional, Kyrylenko, Sergiy, additional, Smyrnova, Kateryna, additional, Buranich, Vladimir V., additional, Horodek, Pawel, additional, Zukowski, Pawel, additional, Koltunowicz, Tomasz N., additional, Galaszkiewicz, Piotr, additional, Makashina, Kristina, additional, Bondariev, Vitaly, additional, Sahul, Martin, additional, Čaplovičová, Maria, additional, Husak, Yevheniia, additional, Simka, Wojciech, additional, Korniienko, Viktoriia, additional, Stolarczyk, Agnieszka, additional, Blacha-Grzechnik, Agata, additional, Balitskyi, Vitalii, additional, Zahorodna, Veronika, additional, Baginskiy, Ivan, additional, Riekstina, Una, additional, Gogotsi, Oleksiy, additional, Gogotsi, Yury, additional, and Pogorielov, Maksym, additional

Published
2023
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32. Response Optimization of LiNbO3 Ultrasonic Transducers for High Temperature Measurement

Author

Zeng, Xiaomei, Pelenovich, Vasiliy O., Zhang, Xiangyu, Xu, Chang, Ding, Yue, Wang, Zheng, Chen, Zhiwen, Zhang, Jun, Yang, Bing, Pogrebnjak, Alexander, and Liu, Sheng

Abstract

LiNbO3 thin-film ultrasonic transducers were deposited using the 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 LiNbO3 transducers. The position of the sample in a plane parallel to the target surface had a significant impact on the transducer morphology, which changed from a columnar structure to a layer with embedded wedges. An exponential correlation between the amplitude of the pulse-echo response and the transducer thickness was found. The structural quality of the transducer layer was the main factor influencing the response amplitude. A temperature sensor in the form of a thin film ultrasonic transducer deposited on a bolt cup was prepared. To measure temperature, a linear dependence between longitudinal wave time-of-flight and bolt temperature was used. The optimization of the response of the transducer allows for more accurate temperature measurements using higher-order pulse echoes.

Published
2024
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35. List of Contributors

Author

Ahmad, Sharif, primary, Ammar, Sh., additional, Bajpai, A.K., additional, Bhatt, Neha, additional, De Riccardis, M. Federica, additional, Dolez, Patricia I., additional, Eng, Kee Kok, additional, Ghasemi, Mostafa, additional, Ismail, Mokhtar Che, additional, Joshaghani, Ali Hassani, additional, Kakooei, Saeid, additional, Kar, Pradip, additional, Le, Xuan Tuan, additional, Li, Lawrence Kwok-Yan, additional, Lone, Mohammad Nadeem, additional, Mishra, Abhilasha, additional, Mohebbi, Hamed, additional, Nguyen, Thien Vuong, additional, Nguyen, Tuan Anh, additional, Nguyen Tri, Phuong, additional, Ouellet Plamondon, Claudiane M., additional, Pogrebnjak, Alexander D., additional, Ramesh, K., additional, Ramesh, S., additional, Rawat, Neha Kanwar, additional, Re, Marilena, additional, Rtimi, Sami, additional, Wani, Irshad A., additional, Wonnie Ma, I.A., additional, Zahidah, Khairina Azmi, additional, Zeb, Gul, additional, Zhou, Zhifeng, additional, and Zia, Abdul Wasy, additional

Published
2019
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42. MXene-Assisted Ablation of Cells with a Pulsed Near-Infrared Laser

Author

Kyrylenko, Sergiy, primary, Gogotsi, Oleksiy, additional, Baginskiy, Ivan, additional, Balitskyi, Vitalii, additional, Zahorodna, Veronika, additional, Husak, Yevheniia, additional, Yanko, Ilya, additional, Pernakov, Mykolay, additional, Roshchupkin, Anton, additional, Lyndin, Mykola, additional, Singer, Bernhard B., additional, Buranych, Volodymyr, additional, Pogrebnjak, Alexander, additional, Sulaieva, Oksana, additional, Solodovnyk, Oleksandr, additional, Gogotsi, Yury, additional, and Pogorielov, Maksym, additional

Published
2022
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44. Comparative Measurements and Analysis of the Electrical Properties of Nanocomposites Ti x Zr 1− x C+α-Cy (0.0 ≤ x ≤ 1.0).

Author

Żukowski, Paweł, Gałaszkiewicz, Piotr, Bondariev, Vitali, Okal, Paweł, Pogrebnjak, Alexander, Kupchishin, Anatolyi, Ruban, Anatolyi, Pogorielov, Maksym, and Kołtunowicz, Tomasz N.

Subjects
NANOCOMPOSITE materials, PERMITTIVITY measurement, CARBON films, AMORPHOUS carbon, ELECTRON transitions
Abstract

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 matrix was amorphous carbon, and the dispersed phase was carbide nanoparticles. AC measurements were performed in the frequency range of 50 Hz–5 MHz at temperatures from 20 K to 373 K. It was found that both conductivity and permittivity relationships are determined by three tunneling mechanisms, differing in relaxation times. The maxima in the low- and high-frequency regions decrease with increasing temperature. The maximum in the mid-frequency region increases with increasing temperature. The low-frequency maximum is due to electron tunneling between the carbon films on the surface of the carbide nanoshells. The mid-frequency maximum is due to electron transitions between the nano size grains. The high-frequency maximum is associated with tunneling between the nano-grains and the carbon shells. It has been established that dipole relaxation occurs in the nanocomposites according to the Cole-Cole mechanism. The increase in static dielectric permittivity with increasing measurement temperature is indicative of a step polarisation mechanism. In the frequency region above 1 MHz, anomalous dispersion—an increase in permittivity with increasing frequency—was observed for all nanocomposite contents. [ABSTRACT FROM AUTHOR]

Published
2022
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45. Microstructure, Mechanical and Tribological Properties of Advanced Layered WN/MeN (Me = Zr, Cr, Mo, Nb) Nanocomposite Coatings

Author

Smyrnova, Kateryna, primary, Sahul, Martin, additional, Haršáni, Marián, additional, Pogrebnjak, Alexander, additional, Ivashchenko, Volodymyr, additional, Beresnev, Vyacheslav, additional, Stolbovoy, Vyacheslav, additional, Čaplovič, Ľubomír, additional, Čaplovičová, Mária, additional, Vančo, Ľubomír, additional, Kusý, Martin, additional, Kassymbaev, Alexey, additional, Satrapinskyy, Leonid, additional, and Flock, Dominik, additional

Published
2022
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48. EVALUATION OF THE PHASE STABILITY, MICROSTRUCTURE AND DEFECTS IN HIGH-ENTROPY CERAMICS AFTER HIGH-ENERGY ION IMPLANTATION

Author

Pogrebnjak, Alexander D., primary, Buranich, Vladimir, additional, Horodek, Pawel, additional, Budzynski, Piotr, additional, Konarski, Piotr, additional, Amekura, Hiroshi, additional, Okubo, Nariaki, additional, Ishikawa, Norito, additional, Bagdasaryan, Artem, additional, Bauyrzhan, Rakhadilov, additional, Tarelnik, Vyacheslav, additional, Sobaszek, Łukasz, additional, Zukowski, Pawel, additional, and Opielak, Marek, additional

Published
2022
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50. Investigation of AC Electrical Properties of MXene-PCL Nanocomposites for Application in Small and Medium Power Generation

Author

Kołtunowicz, Tomasz N., primary, Gałaszkiewicz, Piotr, additional, Kierczyński, Konrad, additional, Rogalski, Przemysław, additional, Okal, Paweł, additional, Pogrebnjak, Alexander D., additional, Buranich, Vladimir, additional, Pogorielov, Maksym, additional, Diedkova, Kateryna, additional, Zahorodna, Veronika, additional, Balitskyi, Vitalii, additional, Serhiienko, Vladyslav, additional, Baginskyi, Ivan, additional, and Gogotsi, Oleksiy, additional

Published
2021
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