TY - GEN A1 - Shulepov, Ivan A. A1 - Kashkarov, Egor B. A1 - Stepanov, Igor B. A1 - Syrtanov, Maxim S. A1 - Sutygina, Alina A1 - Shanenkov, Ivan A1 - Obrosov, Aleksei A1 - Weiß, Sabine T1 - The Formation of Composite Ti-Al-N Coatings Using Filtered Vacuum Arc Deposition with Separate Cathodes T2 - Metals N2 - Ti-Al-N coatings were deposited on high-speed steel substrates by filtered vacuum arc deposition (FVAD) during evaporation of aluminum and titanium cathodes. Distribution of elements, phase composition, and mechanical properties of Ti-Al-N coatings were investigated using Auger electron spectroscopy (AES), X-ray diffraction (XRD), transmission electron microscopy (TEM) and nanoindentation, respectively. Additionally, tribological tests and scratch tests of the coatings were performed. The stoichiometry of the coating changes from Ti0.6Al0.4N to Ti0.48Al0.52N with increasing aluminum arc current from 70 A to 90 A, respectively. XRD and TEM showed only face-centered cubic Ti-Al-N phase with preferred orientation of the crystallites in (220) direction with respect to the sample normal and without precipitates of AlN or intermetallics inside the coatings. Incorporation of Al into the TiN lattice caused shifting of the (220) reflex to a higher 2θ angle with increasing Al content. Low content and size of microdroplets were obtained using coaxial plasma filters, which provides good mechanical and tribological properties of the coatings. The highest value of microhardness (36 GPa) and the best wear-resistance were achieved for the coating with higher Al content, thus for Ti0.48Al0.52N. These coatings exhibit good adhesive properties up to 30 N load in the scratch tests. KW - filtered vacuum arc KW - deposition KW - TiAlN KW - separate cathodes KW - phase composition KW - hardness KW - wear-resistance Y1 - 2017 UR - http://www.mdpi.com/2075-4701/7/11/497/htm U6 - https://doi.org/10.3390/met7110497 SN - 2075-4701 VL - 7 IS - 11 ER - TY - CHAP A1 - Kashkarov, Egor B. A1 - Sutygina, Alina A1 - Nikitenkov, Nikolay A1 - Syrtanov, Maxim S. A1 - Obrosov, Aleksei ED - Tiwari, Ashutosh T1 - Microstructure changes and hydrogenation behaviour of Zr-1Nb alloy after plasma immersion titanium implantation at different time of exposure T2 - American Advanced Materials Congress 2016 N2 - Zirconium alloys are the main construction materials of water-cooled nuclear reactors. Zirconium is used in the core of nuclear reactors as fuel element claddings due to low thermal-neutron capture cross section. Hydrogen is released in the process of water radiolysis or high-temperature oxidation of fuel claddings under loss of coolant accident (LOCA) conditions. The penetration and accumulation of hydrogen in zirconium alloys lead to degradation of their physical and mechanical properties caused by hydrogen embrittlement and delayed hydride cracking [1, 2]. Plasma immersion ion implantation (PIII) is widely used to improve the mechanical properties, corrosion and erosion resistance as well as to decrease hydrogen absorption rate of zirconium [3, 4]. During PIII, a plasma ions are accelerated by high voltage pulsed bias applied to the target. The accelerated ions penetrate in the bulk of the target and modify the deeper layers of materials. Previous studies shown that PIII of titanium improves the protection properties of Zr-2.5Nb alloy from hydrogenation [5]. Moreover, the microdroplets and ion energy have significant impact on hydrogen absorption of the alloys. However, it is necessary to understand the mechanism of hydrogen interaction with the modified layers depending on the time of implantation. In this study, titanium ions were implanted into Zr-1Nb alloy target using filtered vacuum arc source and high frequency short pulser. Coaxial plasma filter was used to reduce the number and size of microdroplets evaporated from the cathode spots. The implantation parameters are: 70 A arc current, 0.15 Pa argon pressure, 1500 V pulsed bias, 100 kHz repetition frequency, 5 μs pulse length and 5-30 min implantation time. Gas-phase hydrogenation was performed at 623 K and 2 atm. hydrogen pressure for 60 min. Surface morphology, phase composition and depth distribution of elements were investigated using scanning electron and atomic force microscopies (SEM and AFM), X-ray diffraction and glow-discharge optical emission spectroscopy (GDOES). It was revealed that the microdroplets and craters with the size of several microns are formed after titanium implantation. The number and size of craters are increased with implantation time from 5 to 30 minutes. It is assumed that the presence of craters on the surface caused by bombardment of an accelerated ion clusters, which is formed due to incorporation (condensation) and ionization of evaporated atoms near the cathode region. Furthermore, the surface becomes rougher and the microstructure changes to fine-grained with an average grain size of 50-100 nm with increase of implantation time. Hydrogenation behaviour depends on the implantation time and differs from the non-treated Zr-1Nb alloy. Hydrogen absorption rate decreases by two times with increase in implantation time from 5 to 30 min. Furthermore, hydrogen preferably accumulates in the modified layer at higher implantation time. The distribution of hydrogen tends to decrease in the depth of implanted layer. The phase state of the alloy has not changed after implantation, however, the extensive distortions of the crystal lattice are observed after hydrogenation of the non-treated and implanted for 5 min Zr-1Nb alloys. KW - implantation KW - titanium KW - zirconium KW - hydrogenation KW - microstructure Y1 - 2016 SN - 978-91-88252-03-6 PB - VBRI Press CY - Linköping ER - TY - GEN A1 - Obrosov, Aleksei A1 - Sutygina, Alina A1 - Volinsky, Alex A. A1 - Manakhov, Anton A1 - Weiß, Sabine A1 - Kashkarov, Egor B. T1 - Effect of Hydrogen Exposure on Mechanical and Tribological Behavior of CrₓN Coatings Deposited at Different Pressures on IN718 T2 - Materials N2 - In the current study, the properties of the CrₓN coatings deposited on the Inconel 718 superalloy using direct current reactive magnetron sputtering are investigated. The influence of working pressure on the microstructure, mechanical, and tribological properties of the CrₓN coatings before and after high-temperature hydrogen exposure is studied. The cross-sectional scanning electron micrographs indicate the columnar structure of the coatings, which changes from dense and compact columns to large columns with increasing working pressure. The Cr/N ratio increases from 1.4 to 1.9 with increasing working pressure from 300 to 900 mPa, respectively. X-ray diffraction analysis reveals a change from mixed hcp-Cr₂N and fcc-CrN structure to approximately stoichiometric Cr₂N phase. After gas-phase hydrogenation, the coating deposited at 300 mPa exhibits the lowest hydrogen absorption at 600 °C of all investigated coatings. The results indicate that the dense mixed cubic and hexagonal structure is preferential for hydrogen permeation resistance due to the presence of cubic phase with higher packing density in comparison to the hexagonal structure. After hydrogenation, no changes in phase composition were observed; however, a small amount of hydrogen is accumulated in the coatings. An increase of coating hardness and elastic modulus was observed after hydrogen exposure. Tribological tests reveal that hydrogenation leads to a decrease of the friction coefficient up to 20%–30%. The best value of 0.25 was reached for hydrogen exposed CrₓN coating deposited at 300 mPa. KW - CrₓN coatings KW - PVD KW - hydrogenation KW - tribology KW - mechanical properties KW - GDOES Y1 - 2017 UR - http://www.mdpi.com/1996-1944/10/5/563/htm U6 - https://doi.org/10.3390/ma10050563 SN - 1996-1944 VL - 10 IS - 5 SP - 563 ER - TY - CHAP A1 - Obrosov, Aleksei A1 - Kashkarov, Egor B. A1 - Weiß, Sabine A1 - Volinsky, Alex A. ED - Tiwari, Ashutosh T1 - Mechanical and tribological behaviour of hydrogenated CrxN coatings deposited at different pressure and voltages on IN718 T2 - American Advanced Materials Congress 2016 N2 - Hydrogen degradation is a serious problem in industrial applications like power plants (boilers, turbines), marine structures, car and aircraft components, as it leads to failures as well as to deterioration of properties. Inconel 718 is one of the most commonly used materials for these applications. Different metal nitrides like TiN coatings have been deposited in past to prevent hydrogen degradation, which are also known for their high hardness and good wear resistance [1, 2]. However, reports on hydrogen degradation of CrN coatings, which shows better oxidation and corrosion resistance, higher temperature stability and lower friction coefficient than TiN [3, 4] has not been reported till now. Despite a lot of publications about CrN films, up to now the effect of hydrogenation on mechanical and tribological properties of CrN coatings is still not completely understood. In the current work CrxN coatings were deposited by Direct Current Magnetron Sputtering (dcMS) on Inconel 718 substrate at different chamber pressures and substrate voltages. Substrate voltage is one of the most important process parameters which determines the structure of the coating and the adhesion between substrate and coating. Simultaneously a study of the chamber pressure is also needed to understand the deposited structure and growth rate because at higher pressures the high number of argon atoms reduce the number of ionized ions available for the deposition leading to low deposition rates [5]. Gas-phase hydrogenation of the samples was performed at a temperature of 600° C and hydrogen pressure of 2 atm. It was found that CrxN coatings are resistant against hydrogen exposure as compared to uncoated surfaces. The results of changes in the mechanical, tribological properties and phase composition of the coatings after hydrogenation are discussed. Coating microstructure was studied by scanning electron microscopy (SEM). The mechanical properties of the coatings were characterized by means of nanoindentation and scratch test. KW - CrxN coating KW - mechanical properties KW - microstructure KW - hydrogenation KW - XRD Y1 - 2016 SN - 978-91-88252-03-6 PB - VBRI Press CY - Linköping ER - TY - GEN A1 - Kashkarov, Egor B. A1 - Nikitenkov, Nikolay A1 - Sutygina, Alina A1 - Laptev, Roman A1 - Bordulev, Yuriy A1 - Obrosov, Aleksei A1 - Liedke, Maciej O. A1 - Zak, Andrzej A1 - Weiß, Sabine T1 - Microstructure, defect structure and hydrogen trapping in zirconium alloy Zr-1Nb treated by plasma immersion Ti ion implantation and deposition T2 - Journal of Alloys and Compounds N2 - The effect of low energy plasma immersion ion implantation and deposition of titanium on microstructure, defect structure and hydrogen trapping in zirconium alloy Zr-1Nb was studied. Defect structure and distribution were analyzed by Doppler broadening using slow positron beam. The surface microstructure after modification is represented by nanostructured Ti grains with random orientation. The gradient distribution of titanium as well as vacancy type defects were analyzed. The concentration of vacancy type defects is rising with increasing bias voltage. Gas-phase hydrogenation of the Ti-modified Zr-1Nb alloy was performed at 400 °C for 60 min. The strong interaction of hydrogen with vacancy type defects was demonstrated. Two different changes in the defect structure after hydrogenation were observed: when a titanium film is formed on the surface (after deposition at 500 V) hydrogen trapping occurs with the formation of titanium hydride phases, while in the implanted layer (deposition at 1000 and 1500 V) hydrogen is trapped due to interaction with vacancy type defects. The physical basis of Ti diffusion and its influence on the evolution of defect structure after surface modification and hydrogenation were discussed. KW - Zirconium KW - Ion implantation KW - Titanium KW - Diffusion KW - Surface modification KW - Hydrogen trapping KW - Microstructure KW - Slow positrons KW - Doppler broadening KW - Defects Y1 - 2018 UR - http://www.sciencedirect.com/science/article/pii/S0925838817335879 U6 - https://doi.org/10.1016/j.jallcom.2017.10.151 SN - 0925-8388 VL - 732 SP - 80 EP - 87 ER - TY - GEN A1 - Obrosov, Aleksei A1 - Sutygina, Alina A1 - Manakhov, Anton A1 - Bolz, Sebastian A1 - Weiß, Sabine A1 - Kashkarov, Egor B. T1 - Oxidation Behavior of Zr–1Nb Corroded in Air at 400 °C after Plasma Immersion Titanium Implantation T2 - Metals N2 - In this paper, the influence of plasma immersion titanium implantation into the zirconium alloy Zr-1Nb on the oxidation behavior at 400 °C for 5, 24, 72, and 240 h in air under normal atmospheric pressure (101.3 kPa) was shown. The influence of implantation on the protective properties of the modified layer was shown. The valence of the oxides before and after implantation was analyzed by means of X-ray photoelectron spectroscopy (XPS). Grazing incidence X-ray diffraction (GIXRD) was carried out to examine the phase composition after titanium ion implantation and oxidation. Differential scanning calorimetry (DSC) revealed that titanium implantation exhibited effects of stabilizing the β phase. The formation of the t-ZrO2 and m-ZrO2 was observed during the oxidation of the as-received and modified Zr-1Nb. The measurement of weight gain showed an improvement in oxidation resistance of Ti implanted Zr-1Nb at the oxidation up to 24 h when compared with that of the as-received Zr-1Nb. However, at longer oxidation cycle the oxidation rate of Ti-implanted zirconium alloy is the same with the as-received alloy, which attributed to the layer thickness. Nevertheless, the corrosion of the Ti-implanted alloy is more uniform, while a local corrosion and cracks was detected on the surface of the as-received alloy. KW - zirconium alloy KW - titanium KW - ion implantation KW - PIII KW - oxidation KW - DSC KW - XPS KW - surface morphology KW - X-ray diffraction Y1 - 2018 UR - http://www.mdpi.com/2075-4701/8/1/27/htm U6 - https://doi.org/10.3390/met8010027 SN - 2075-4701 VL - 8 IS - 1 ER - TY - GEN A1 - Kashkarov, Egor B. A1 - Nikitenkov, Nikolay A1 - Sutygina, Alina A1 - Obrosov, Aleksei A1 - Manakhov, Anton A1 - Polčak, Josef A1 - Weiß, Sabine T1 - Hydrogen absorption by Ti-implanted Zr-1Nb alloy T2 - International journal of hydrogen energy N2 - This paper describes the hydrogenation behavior of Zr-1Nb alloy Ti-implanted by plasma immersion ion implantation (PIII). Hydrogen sorption kinetics of the Ti-modified alloy was investigated under gas-phase hydrogenation at 400 °C for 1 h. The influence of implantation time on the protective properties of the modified layer was shown. The lowest hydrogen absorption as well as the highest hydrogen trapping efficiency was achieved after PIII for 30 min. The main contribution to the reduction of hydrogen permeation is the formation of an oxide layer consisting of mixed TiO2 and ZrO2 on the modified surface of the alloy. X-ray photoelectron spectroscopy (XPS) revealed that PIII titanium oxide exists on the surface in the form of TiO2, which transforms to mixed Ti2O3 and TiO2 after hydrogenation. The thickness of the modified layer increases with implantation time that improves the efficiency of hydrogen trapping. All the absorbed hydrogen is gradually distributed in the modified layer and no hydrides are formed after hydrogenation in Ti-modified Zr-1Nb for 15 and 30 min. KW - Zirconium KW - Titanium implantation KW - Hydrogenation KW - X-ray photoelectron spectroscopy KW - Glow discharge optical emission spectroscopy KW - X-ray diffraction Y1 - 2018 UR - https://www.sciencedirect.com/science/article/pii/S0360319917346359 U6 - https://doi.org/10.1016/j.ijhydene.2017.12.003 SN - 0360-3199 VL - 43 IS - 4 SP - 2484 EP - 2491 ER - TY - GEN A1 - Kashkarov, Egor B. A1 - Obrosov, Aleksei A1 - Sutygina, Alina A1 - Uludintceva, Elena A1 - Mitrofanov, Andrei A1 - Weiß, Sabine T1 - Hydrogen Permeation, and Mechanical and Tribological Behavior, of CrNx Coatings Deposited at Various Bias Voltages on IN718 by Direct Current Reactive Sputtering T2 - Coatings N2 - In the current work, the microstructure, hydrogen permeability, and properties of chromium nitride (CrNₓ) thin films deposited on the Inconel 718 superalloy using direct current reactive sputtering are investigated. The influence of the substrate bias voltage on the crystal structure, mechanical, and tribological properties before and after hydrogen exposure was studied. It was found that increasing the substrate bias voltage leads to densification of the coating. X-ray diffraction (XRD) results reveal a change from mixed fcc-CrN + hcp-Cr₂N to the approximately stoichiometric hcp-Cr₂N phase with increasing substrate bias confirmed by wavelength-dispersive X-ray spectroscopy (WDS). The texture coefficients of (113), (110), and (111) planes vary significantly with increasing substrate bias voltage. The hydrogen permeability was measured by gas-phase hydrogenation. The CrN coating deposited at 60 V with mixed c-CrN and (113) textured hcp-Cr₂N phases exhibits the lowest hydrogen absorption at 873 K. It is suggested that the crystal orientation is only one parameter influencing the permeation resistance of the CrNx coating together with the film structure, the presence of mixing phases, and the packing density of the structure. After hydrogenation, the hardness increased for all coatings, which could be related to the formation of a Cr₂O₃ oxide film on the surface, as well as the defect formation after hydrogen loading. Tribological tests reveal that hydrogenation leads to a decrease of the friction coefficient by up to 40%. The lowest value of 0.25 ± 0.02 was reached for the CrNₓ coating deposited at 60 V after hydrogenation. KW - CrNx coatings KW - Physical Vapour Deposition (PVD) KW - hydrogenation KW - tribology KW - mechanical properties KW - X-ray diffraction Y1 - 2018 UR - http://www.mdpi.com/2079-6412/8/2/66/htm U6 - https://doi.org/10.3390/coatings8020066 SN - 2079-6412 N1 - Special Issue "Surface Preparation and Treatments for Enhancing the Coating Performance" VL - 8 IS - 2 ER - TY - GEN A1 - Kashkarov, Egor B. A1 - Nikitenkov, Nikolay A1 - Sutygina, Alina A1 - Syrtanov, Maxim S. A1 - Zakharchenko, S. A1 - Obrosov, Aleksei T1 - Influence of Plasma-Immersion Titanium-Ion Implantation on the Kinetics of Hydrogen Penetration into E110 Zirconium Alloy T2 - Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques N2 - The influence of plasma-immersion titanium-ion implantation on the hydrogen saturation of E110 zirconium alloy is described. Titanium ions are implanted from the metal plasma of an arc discharge at an accelerating-pulse bias potential of 1.5 kV (the pulse-repetition frequency is 100 kHz, and the pulse length is 5 μs) for 30 min. The phase composition, morphology, and valence state of the alloy surface layer are studied. Comparative analysis of changes in the hardness and wear resistance of the alloy subjected to implantation is performed. It is demonstrated that the rate of hydrogen penetration into the surface-doped alloy decreases substantially at a gas-phase hydrogenation temperature of 400°C. KW - ion implantation KW - zirconium KW - titanium KW - hydrogen sorption KW - wear resistance KW - X-ray photoelectron spectroscopy Y1 - 2018 UR - https://link.springer.com/journal/11700 U6 - https://doi.org/10.1134/S102745101803031X SN - 1819-7094 VL - 12 IS - 3 SP - 570 EP - 575 ER - TY - GEN A1 - Petkov, Nikolay A1 - Kashkarov, Egor B. A1 - Obrosov, Aleksei A1 - Bakalova, Totka A1 - Kejzlar, Pavel A1 - Bahchedzhiev, Hristo T1 - Influence of Bias Voltage and CH4/N2 Gas Ratio on the Structure and Mechanical Properties of TiCN Coatings Deposited by Cathodic Arc Deposition Method T2 - Journal of Materials Engineering and Performance N2 - This article presents a study of the influence of the bias voltage and CH4/N2 gas ratio on the structure and mechanical properties of TiCN coatings. The coatings are deposited by cathodic arc deposition technology from Ti cathodes under an atmosphere of a mixture of CH4 and N2 gasses. XRD analysis shows that an increase in the methane flow changes the preferential orientation of the coating from (111) to (200) and results in a refinement of the structure (grain size reduction from 23 to 7 nm). SEM analysis shows that the coatings are stoichiometric. It was demonstrated that the bias voltage has an influence on the grain size, hardness and elasticity module. The highest hardness value of 52.5 GPa was measured at the coatings lacking a clear preferential orientation. The adhesion of the coatings showed a critical load in the range of 29-64 N. KW - cathodic arc deposition KW - nanohardness KW - TiCN coatings KW - XRD analysis Y1 - 2018 UR - https://link.springer.com/article/10.1007/s11665-018-3754-3 U6 - https://doi.org/10.1007/s11665-018-3754-3 SN - 1544-1024 SN - 1059-9495 VL - 28 IS - 1 SP - 343 EP - 354 ER - TY - GEN A1 - Obrosov, Aleksei A1 - Sutygina, Alina A1 - Kashkarov, Egor B. A1 - Weiß, Sabine T1 - Oxidation behavior of Zr–1Nb in air at 400°C after Titanium Plasma Immersion Ion Implantation N2 - Zirconium alloys have been widely used in nuclear reactors due to low thermal neutron capture cross-section, excellent corrosion resistance and acceptable mechanical properties [1, 2]. Nowadays several methods apply for improving hydrogen and corrosion resistance such as addition of stabilizing additives (yttrium) [3, 4], deposition of thin solid films [5, 6], micro-arc oxidation [7] and modification of the surface by electron beam [8, 9]. Despite the multiplicity of the methods hydrogen embrittlement is still a pressing issue. Previous results [10, 11] have shown the positive influence of plasma immersion titanium implantation on the hydrogenation behavior of Zr–1Nb and Zr–2.5 Nb. After Ti implantation hydrogen preferably accumulates in the modified surface layer comprising the implanted Ti. Furthermore, the hydrogen concentration is considerably less inside the zirconium modified sample than in the as-received samples. The integration of elements into the zirconium lattice can influence the valence of the surface and change corrosion and oxidation rates of the alloys. So it is very important not to decrease the zirconium oxidation resistance due to Ti implantation. Therefore, the purpose of this research is to study of the influence of Ti implantation on surface morphology, oxidation rate and phase structure of the Zr–1Nb alloy after oxidation on air at 400 0C for 5, 24, 72 and 240 h. The surface structure of the samples and their elemental composition were investigated with the scanning electron microscope Mira II XMH (Tescan) with energy dispersive x-ray spectroscopy system (EDS). X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC) as well as X-ray diffraction (XRD) was used to characterise the influence of titanium implantation on the oxidation behaviour. The results show that the oxidation kinetics after Ti modification of the zirconium alloy changed. Although the weight gain of the implanted sample remains approximately the same, it can be considered that Ti implantation stabilizes the oxide layer and has beneficial influence on the oxidation protection of Zr-1Nb. KW - Zr–1Nb KW - titanium ion implantation KW - oxidation KW - DSC KW - plasma immersion ion implantation (PIII) Y1 - 2018 UR - https://www.pse-conferences.net/tl_files/abstract-print/PSE2018-PO4029.pdf ER - TY - GEN A1 - Kashkarov, Egor B. A1 - Ryabchikov, Alexander I. A1 - Kurochkin, Alexander A1 - Syrtanov, Maxim S. A1 - Shevelev, Alexey A1 - Obrosov, Aleksei A1 - Weiß, Sabine T1 - Hydrogen Interaction with Deep Surface Modified Zr-1Nb Alloy by High Intensity Ti Ion Implantation T2 - Metals N2 - A deep surface modified TiZr layer was fabricated by high-intensity low-energy titanium ion implantation into zirconium alloy Zr-1Nb. Gas-phase hydrogenation was performed to evaluate protective properties of the modified layer against hydrogen permeation into Zr-1Nb alloy. The effects of ion implantation and hydrogen on microstructure, phase composition and elemental distribution of TiZr layer were analyzed by scanning electron microscopy, X-ray diffraction, and glow-discharge optical emission spectroscopy, respectively. It was revealed that TiZr layer (~10 μm thickness) is represented by α′ + α(TiZr) lamellar microstructure with gradient distribution of Ti through the layer depth. It was shown that the formation of TiZr layer provides significant reduction of hydrogen uptake by zirconium alloy at 400 and 500 °C. Hydrogenation of the modified layer leads to refinement of lamellar plates and formation of more homogenous microstructure. Hydrogen desorption from Ti-implanted Zr-1Nb alloy was analyzed by thermal desorption spectroscopy. Hydrogen interaction with the surface modified TiZr layer, as well as its resistance properties, are discussed. KW - zirconium alloy KW - titanium KW - low energy ion implantation KW - hydrogen KW - sorption KW - microstructure KW - morphology KW - martensitic phase Y1 - 2018 UR - https://www.mdpi.com/2075-4701/8/12/1081/htm U6 - https://doi.org/10.3390/met8121081 SN - 2075-4701 VL - 8 IS - 12 ER - TY - GEN A1 - Kashkarov, Egor B. A1 - Syrtanov, Maxim S. A1 - Murashkina, Tatyana A1 - Kurochkin, Alexander A1 - Shanenkova, Yulia A1 - Obrosov, Aleksei T1 - Hydrogen Sorption Kinetics of SiC-Coated Zr-1Nb Alloy T2 - Coatings N2 - This paper describes the influence of silicon carbide (SiC) coating on hydrogen sorption kinetics of zirconium alloy E110 (Zr-1Nb). Amorphous SiC coating of 1.5-μm thickness was deposited on Zr-1Nb alloy substrate by direct current magnetron sputtering of composite cathode. Hydrogen absorption by SiC-coated Zr-1Nb alloy significantly decreased due to low hydrogen permeability of the coating. Hydrogenation tests show that SiC coating provides protective properties against hydrogen permeation in the investigated temperature range of 350–450 °C. It was shown that hydrogenation of uncoated Zr-1Nb leads to formation of δ hydrides at 350 °C and δ and γ hydrides at higher temperatures whereas in the SiC-coated Zr-1Nb alloy only δ hydrides formed. Gradient hydrogen distribution through the SiC coating and H trapping in the carbon-rich interface was observed. The adhesion strength of the coating was ~5 N. Hydrogenation up to 450 °C for 5 h does not degrade the adhesion properties during scratch testing. KW - hydrogen sorption KW - hydrogenation KW - zirconium alloys KW - E110 (Zr-1Nb) KW - SiC coating KW - magnetron sputtering KW - adhesion Y1 - 2019 UR - https://www.mdpi.com/2079-6412/9/1/31 U6 - https://doi.org/10.3390/coatings9010031 SN - 2079-6412 VL - 9 IS - 1 ER - TY - GEN A1 - Ryabchikov, Alexander I. A1 - Kashkarov, Egor B. A1 - Shevelev, Alexey A1 - Obrosov, Aleksei A1 - Sivin, D. O. T1 - Surface modification of Al by high-intensity low-energy Ti-ion implantation: Microstructure, mechanical and tribological properties T2 - Surface and Coatings Technology N2 - A high-intensity metal ribbon ion beam was generated using plasma immersion extraction and the acceleration of the metal ions with their subsequent ballistic focusing using a cylindrical grid electrode under a repetitively pulsed bias. To generate the dense metal plasma flow, two water-cooled vacuum arc evaporators with Ti cathodes were used. The ion current density reached 43 mA/cm2 at the arc discharge current of 130 A. High-intensity ion implantation (HIII) with a low ion energy ribbon beam was used for the surface modification of the aluminium. The irradiation fluence was changed from 1.5 × 1020 ion/cm2 to 4 × 1020 ion/cm2 with a corresponding increase in the implantation temperature from 623 to 823 K. The structure and composition of the Ti-implanted aluminium were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). The mechanical properties and wear resistance were measured using nanoindentation and “pin-on-disk” testing, respectively. It was shown that the HIII method can be used to form a deep intermetallic Al3Ti layer. It has been established that a thin (0.4 μm) modified layer with a hcp Ti(Al) structure is only formed on the surface at 623 K, while the formation of the ordered Al3Ti intermetallic phase occurs at the implantation temperatures of 723 and 823 K. Despite the significant ion sputtering of the surface, the thickness of the modified layer increases from ~1 μm to ~6 μm, and the implantation temperature rises from 723 to 823 K. It was found that the homogeneous intermetallic Al3Ti layer with a thickness of up to 5 μm was formed at 823 К. The mechanical and tribological properties of the aluminium were substantially improved after HIII. For the Ti-implanted aluminium, the hardness of the surface layer increases from 0.4 GPa (undoped Al) to 3.5–4 GPa, while the wear resistance increases by more than an order of magnitude. KW - Ion implantation KW - Ribbon ion beam KW - Intermetallics KW - Aluminium KW - Titanium KW - Surface modification Y1 - 2019 UR - https://www.sciencedirect.com/science/article/pii/S0257897219304992?via%3Dihub U6 - https://doi.org/10.1016/j.surfcoat.2019.05.020 SN - 0257-8972 VL - 372 SP - 1 EP - 8 ER - TY - GEN A1 - Obrosov, Aleksei A1 - Kashkarov, Egor B. A1 - Sharma, A. A1 - Weiß, Sabine T1 - Microstructure and defect structure of Zr-1Nb alloy deep surface modified by high Intensity Ti Ion implantation T2 - MC Microscopy Conference, 01-05 September 2019, Berlin, Abstracts N2 - A deep surface modified TiZr layer was fabricated by high-intensity low-energy titanium ion implantation into zirconium alloy Zr-1Nb alloy with the various dose in the range of (5.4–9.56) × 1020 ion/cm2. The gradient distribution of titanium as well as vacancy type defects were analysed. The effects of ion implantation on microstructure, phase composition and elemental distribution of TiZr layer were analysed by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and glow-discharge optical emission spectroscopy, respectively. The results show the appearance of Zr-Ti intermetallic phases of different stoichiometry after Ti implantation. The intermetallic phases are transformed from both Zr0.7Ti0.3 and Zr0.5Ti0.5 to single Zr0.6Ti0.4 phase with the increase in the implantation dose. The depth of Ti penetration into the bulk of Zr increases from 6 to 13 μm with the implantation dose. The higher current density (170 mA/cm2) leads to the increase in the grain size and surface roughness. It was revealed that TiZr layer (~10 μm thickness) is represented by α′ + α(TiZr) lamellar microstructure with gradient distribution of Ti through the layer depth. Transmission electron microscopy was used for investigation of the physical basis of Ti diffusion and its influence on the evolution of the defect structure after surface modification. Furthermore, it was found that on the surface between substrate and implanted layer was found an amorphous layer, which occur as a result of further stress accumulations from the higher implantation doses. Y1 - 2019 UR - https://epub.uni-regensburg.de/40685/1/MC%202019_Proceedings.pdf SP - 86 CY - Berlin ER - TY - GEN A1 - Shevelev, Alexey A1 - Kashkarov, Egor B. A1 - Ryabchikov, Alexander I. A1 - Syrtanov, Maxim S. A1 - Obrosov, Aleksei T1 - Surface Modification of E110 Alloy by High-Intensity Low Ion Energy Cr Implantation T2 - The 21st International Conference on Surface Modification of Materials by Ion Beams, 25-30 August 2019 N2 - The Fukushima disaster has strongly effected on nuclear energetics and their progress [1]. It pointed to a crucial oxidation and subsequent destruction of nuclear fuel claddings in light-water reactors in the case of loss of coolant accident conditions. Surface modification is one of the promising approaches to protect Zr alloys in normal operation and accident conditions of nuclear reactors [2]. Surface modified layers or coatings forming chromia during oxidation is of greatest interest since it meets the basic requirements for accident tolerant fuel materials [3]. The aim of this research is to study the possibility of deep surface modification of zirconium alloy E110 by high intensity ion implantation using low energy metal ion beam. The formation of the metal ion beams is provided by the application of negatively pulsed bias (1.5 kV) to the system immersed in the chromium vacuum arc plasma. The structure and composition of Cr-implanted zirconium alloy were studied by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The mechanical properties and wear resistance were measured by nanoindentation and «ball on disk» testing, respectively. The influence of implantation temperature on the phase composition, microstructure, and mechanical properties as well as on the corrosion behavior of Cr-implanted zirconium alloy under high-temperature oxidation (up to 1100÷1200 °C) have been described. Y1 - 2019 UR - https://smmib.ru/assets/files/SMMIB2019_TOMSK_full.pdf#page=176 SP - 109 EP - 109 CY - Tomsk ER - TY - GEN A1 - Kashkarov, Egor B. A1 - Ryabchikov, Alexander I. A1 - Syrtanov, Maxim S. A1 - Obrosov, Aleksei A1 - Zacharchenko, S. T1 - ФОРМИРОВАНИЕ ГЛУБОКИХ МОДИФИЦИРОВАННЫХ СЛОЕВ TIZR НА ПОВЕРХНОСТИ ЦИРКОНИЕВОГО СПЛАВА Э110 МЕТОДОМ ВЫСОКОИНТЕНСИВНОЙ ИОННОЙ ИМПЛАНТАЦИИ T2 - 24rd International Conference on Ion-Surface Interactions N2 - This work describes the effect of high-intensity low ion energy implantation on the structure and properties of the surface modified layer forming on zirconium alloy. The influence of irradiation dose on the microstructure, phase composition, thickness and mechanical properties of surface modified zirconium alloy were investigated. T2 - Formation of deep modified TiZr layers on the surface of zirconium E110 alloy using high-intensity ion implantation, 19-23. August 2019 Y1 - 2019 UR - https://elibrary.ru/item.asp?id=41212236 SP - 190 EP - 193 CY - Moscow ER - TY - GEN A1 - Fellah, Mamoun A1 - Hezil, Naouel A1 - Touhami, Mohamed Zine A1 - Obrosov, Aleksei A1 - Weiß, Sabine A1 - Kashkarov, Egor B. A1 - Lider, Andrey M. A1 - Montagne, Alex A1 - Iost, Alain T1 - Enhanced Structural and Tribological Performance of Nanostructured Ti–15Nb Alloy for Biomedical Applications T2 - Results in Physics N2 - Low modulus β-type Ti-15Nb alloys were prepared by subjecting them to different sintering temperatures (800, 900, 1000 and 1100 °C) and their morphological and structural properties were evaluated. X-ray diffraction analysis was used for the morphological characterization which indicated that the mean pore and crystallite size continuously decreased with increasing sintering temperature to reach the lowest values of 41 nm and 27.5 nm at 1100 °C, respectively. Moreover, the higher sintering temperature resulted in higher relative density, greater hardness and young’s modulus of the Ti-15Nb alloys. Wear tests were conducted using a ball-on-plate type Oscillating tribometer, under different applied loads (2, 8 and 16 N) to evaluate their tribological characterization. The wear rate and friction coefficient were lower at higher sintering temperature. This enhancement in tribological properties was attributed to a grain refinement. The Ti-15Nb alloys sintered at 1100 °C showed the best tribological performance. KW - Tribological properties KW - Sintering KW - Biomaterial KW - β-Ti Alloys KW - Ti-15Nb alloys KW - Milling Y1 - 2019 UR - https://www.sciencedirect.com/science/article/pii/S2211379719300506 U6 - https://doi.org/10.1016/j.rinp.2019.102767 SN - 2211-3797 VL - 15 ER - TY - GEN A1 - Petkov, Nikolay A1 - Bakalova, Totka A1 - Obrosov, Aleksei A1 - Kashkarov, Egor B. A1 - Kormunda, Martin A1 - Kejzlar, Pavel A1 - Bahchedzhiev, Hristo A1 - Dadourek, Karel A1 - Weiß, Sabine T1 - Structural, mechanical, and tribological properties of CrCN coatings obtained by cathodic arc physical vapour deposition technology at different CH4/N2 gas ratio T2 - Thin Solid Films N2 - Chromium carbonitride coatings were deposited by cathodic arc physical vapor deposition technology at a temperature of 300 °C, as were used the reactive gasses CH4 and N2. The structural analysis of the CrN coating showed a polycrystalline structure with mixed CrN and Cr2N phases. All studied coatings, including the CrC exhibits fcc structure. The phases were confirmed by X-ray photoelectron spectroscopy measurements where a surface oxidation was also detected. The increase of the CH4 gas flow during the deposition process leads to a parabolic trend with the highest hardness of 33.5 GPa for the coating deposited at CH4 / N2 = 0.53. At the same time the lowest coefficient of friction for both counterparts Al2O3 and ZrO2 (0.28 and 0.26, respectively) were measured at CH4 / N2 = 1.86. The tribological tests reveal that the wear of the coatings increases with an increasing CH4 flow rate, whereas the coefficient of friction decreases. This observed contradiction is explained by a phenomenon described as the effect of Rebinder. KW - Chromium carbonitride KW - Cathodic arc deposition KW - X-ray diffraction KW - X-ray photoelectron spectroscopy KW - Mechanical properties KW - Wear Y1 - 2023 UR - https://www.sciencedirect.com/science/article/pii/S0040609022005715 U6 - https://doi.org/10.1016/j.tsf.2022.139669 SN - 1879-2731 VL - 766 ER -