@misc{RimHezilFellahetal., author = {Rim, Imen and Hezil, Naouel and Fellah, Mamoun and Saoudi, Adel and Obrosov, Aleksei and El-Hiti, Gamal A.}, title = {Enhancing kaolin performance through organic molecule modification and assessing its efficiency for lead and copper adsorption}, series = {Environmental Technology \& Innovation}, volume = {36}, journal = {Environmental Technology \& Innovation}, number = {November 22024}, issn = {2352-1864}, doi = {10.1016/j.eti.2024.103904}, pages = {1 -- 19}, abstract = {The research aimed to enhance the efficacy of kaolin in water treatment by incorporating diphenylamine (DPA) and to evaluate its effectiveness in adsorbing lead and copper in wastewater in comparison to natural kaolin (Nat-kaolin). This entailed modifying kaolin with DPA to create DPA-kaolin and conducting comprehensive characterization utilizing a range of techniques, including X-ray diffraction analysis (XRD), scanning electron microscope (SEM), energy dispersion X-ray (EDX), thermogravimetric analysis (TGA), differential thermal analysis (DTA), Fourier-transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) analysis. The results demonstrated the successful modification of DPA, as evidenced by an increase in BET-specific surface area of about 25 \% (from 66.69 m².g-1 to 71.35 m².g-1), indicating enhanced adsorption capacity. XRD analysis confirmed the composition of the samples, while TGA/DTA indicated changes in water adsorption and dehydroxylation. SEM and EDX illustrated the tubular nature of the clay with a decrease in the amount of Al, about 10.76 \%, and the amount of Si, about 10.38 \%, on the DPA-kaolin. Notably, the FTIR spectrum of DPA-kaolin showed the presence of new vibration bands at 1248 cm-1, indicating the presence of DPA. In terms of adsorption, the DPA-kaolin exhibited significantly higher maximum adsorption capacities for Pb(II) and Cu(II) compared to the nat-kaolin, with values of 151 µmol/g and 134 µmol/g, respectively.These values were significantly higher than those observed for Nat-kaolin, which demonstrated adsorption capacities of 103 µmol/g for Pb(II) and 91 µmol/g for Cu(II). The adsorption kinetics indicated that the pseudo-second-order kinetic model described the sorption mechanism for both Pb(II) and Cu(II). This was evidenced by the values of R², which were 0.999 and 0.996, respectively. The study provides clear evidence that DPA-kaolin is more effective than Nat-kaolin in removing lead (Pb(II)) and copper (Cu(II)) from wastewater. Through rigorous experimentation, it was observed that DPA-kaolin exhibited notably enhanced adsorption capabilities for both Pb(II) and Cu(II) compared to Nat-kaolin. These findings serve to emphasize the practical importance and potential utility of the modification, offering promising prospects for the development of more efficient wastewater treatment methodologies.}, language = {en} } @misc{BourasFellahBarilleetal., author = {Bouras, Dikra and Fellah, Mamoun and Barille, Regis and Obrosov, Aleksei and Ikbal, Amjad and Avramov, Pavel V. and El-Hiti, Gamal A.}, title = {Multiple layers, porous surface, and their role in increasing the efficiency of photocatalytic coating on (DD3, DD3+ZrO2) ceramics and glass}, series = {Ceramics International}, volume = {50}, journal = {Ceramics International}, number = {21, C}, issn = {1873-3956}, doi = {https://doi.org/10.1016/j.ceramint.2024.08.239}, pages = {43854 -- 43873}, abstract = {Magnesium-doped zinc oxide thin films were dip-coated onto porous ceramic and glass substrates under identical conditions (50 layers, same doping ratio). Structural, morphological, and photocatalytic properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), UV-visible spectrophotometry, and confocal microscopy. XRD analysis indicated a shift in peak positions towards higher angles, increased grain size, and lattice distortion on both substrates. Unique flower-shaped crystalline granulates were observed exclusively on the ceramic substrate (DD3Z). The energy gap decreased on the ceramic and increased on the glass substrate. The photocatalytic activity was evaluated using an aqueous orange II solution, showing significantly higher decomposition (80 ± 0.53 \% after 6 h) on the ceramic compared to the glass substrate (30 \%). The enhanced performance on ceramic substrates, particularly with DD3+ZrO2, was attributed to increased microporosity, surface roughness, and active material incorporation, facilitating greater photocatalytic efficiency. The findings suggest promising applications of these materials for efficient and cost-effective photocatalysis, with potential for reuse after thermal treatment at 500 °C.}, language = {en} } @misc{FellahHezilBourasetal., author = {Fellah, Mamoun and Hezil, Naouel and Bouras, Dikra and Habeeb, Majeed Ali and Hamadi, Fouzia and Bouchareb, Nabila and Laouini, Salah Eddine and Larios, Alejandro Perez and Obrosov, Aleksei and El-Hiti, Gamal A.}, title = {Microstructural and photocatalytic properties of nanostructured near-β Ti-Nb-Zr alloy for total hip prosthesis use}, series = {Kuwait Journal of Science}, volume = {51}, journal = {Kuwait Journal of Science}, number = {4}, publisher = {Elsevier}, issn = {2307-4116}, doi = {https://doi.org/10.1016/j.kjs.2024.100276}, pages = {1 -- 12}, abstract = {With its unique corrosion resistance, light weight, mechanical strength, and biocompatibility, TNZ is a versatile metal alloy that is used in the aerospace and medical industries. The current study aims to investigate the effect of milling time (2, 12, 24, and 36 h) on the nanostructured ternary alloy Ti-25Nb-25Zr (TNZ) prepared by high energy ball milling, a process involving the use of a high-energy ball mill to mix and grind the alloy powders, on its structural, physical, and photocatalytic characterizations. The alloys' characteristics, such as morphology, structural properties, relative density/porosity, surface roughness, hardness, and Young's modulus, were evaluated using SEM, XRD, surface profilometer, and microdurometer, respectively. The photocatalytic characterization was conducted by measuring their absorbance as a function of time using a spectrophotometer of visible and ultraviolet light in the wavelength range of 250-650 nm. Results showed that the crystallite and mean pore size reduced with increasing milling time, with the smallest values of 25 nm and 34 μm, respectively, after 36 h. This indicates that longer milling times result in a more compact and uniform structure, which could enhance the mechanical properties of the alloy. Structural characterization shows that the amount of the β-Ti phase increased with increasing milling time, resulting in the spherical morphology and texturing of the synthesized alloys. The milled alloys' structural evolution and morphological changes were sensitive to their milling times. Also, the relative density, Young's modulus, and hardness increased, reaching values of 89 \%, 105 GPa, and 352 HV, respectively, due to grain size decreasing with increasing milling time. This suggests that longer milling times lead to a denser and harder alloy, which could be beneficial for its use in total hip prostheses. The photocatalytical characterization demonstrated that the degradation of orange II (OII) increased with increasing milling time. The Ti-25Nb-25Zr catalyst gave the best degree of degradation, which meant that the decolorization process could be operated rapidly and at a relatively low cost without UV irradiation.}, language = {en} } @misc{BourasFellahBarilleetal., author = {Bouras, Dikra and Fellah, Mamoun and Barille, Regis and Obrosov, Aleksei and El-Hiti, Gamal A.}, title = {Production of novel Zr-Mg nanoceramics based on kaolinite clay with strong antibacterial activity}, series = {Ceramics International}, volume = {50}, journal = {Ceramics International}, number = {16}, publisher = {Elsevier}, issn = {1873-3956}, doi = {https://doi.org/10.1016/j.ceramint.2024.05.091}, pages = {27949 -- 27960}, abstract = {Gram-negative bacteria Pseudomonas putida, Gram-positive Bacillus subtilis, and Staphylococcus aureus were utilized as test samples to evaluate the antibacterial characteristics of DD3-clay/MgO and DD3+38 wt\% ZrO2-clay/MgO nanoparticles. The ceramic powders prepared by a thermal autoclave method are characterized before and after Mg addition by SEM, EDX, XRD, IR, UV-visible, and TEM in order to investigate microstructure, phase, and surface morphology. The results showed that after adding Mg, it led to the deformation of the crystal lattices of (mullite, zirconium silicate, and zirconium oxide) together with a decrease in particle size (75-103 nm) and a complete change in its shape from nanotube to nanospherical, as observed by SEM and TEM analyses. It also confirmed by UV-visible spectroscopy that the addition of Mg increases the absorbance accompanying a decrease in the energy gap of 1.91, 1.74, 1.73, and 1.43 eV corresponding to DD3, DD3Z, DD3/30 wt\% Mg and DD3Z/30 wt\% Mg respectively. The antibacterial mechanism is related to the size of the particles, the solvent used for powder dissolution, the nanoparticle's size when they come into touch with bacteria, and the generation of reactive oxygen species (ROS: ˙O2-, ˙OH, and H2O2). It was observed that the anti-bacterial activity is enhanced with 10 wt\% and 30 wt\% of Mg added to a modified ceramic powder. Also, more O2- is formed on the surface of the prepared powder, which penetrates the bacterial cell and destroys it. The nanocomposite particles showed remarkable antibacterial activity when they were dissolved in DMSO compared to methanol and chloroform as organic solvents. The aim is to enrich knowledge on the antibacterial activities of metal nanoparticles (ZrSiO4 and MgO) on three bacterial strains with different Grams due to their extensive involvement in the phenomena of contamination and infection encountered in the medical field. The synthesized nanoparticles have good antimicrobial activity against all strains tested. A maximum inhibition zone of 35 ± 0.2 mm was obtained with S. aureus, a zone of 23 ± 0.46 mm with P. putida and a zone of 27 ± 0.46 nm with B. subtilis for DD3/30 wt\% Mg and an inhibition zone of 38 ± 0.93 mm, 26 ± 0.24 nm and 17 ± 0.33 nm was obtained with same strains for DD3Z/30 wt\% Mg, respectively.}, language = {en} } @misc{SellamAziziBourasetal., author = {Sellam, Manel and Azizi, Soulef and Bouras, Dikra and Fellah, Mamoun and Obrosov, Aleksei and El-Hiti, Gamal A.}, title = {Degradation of rhodamine B dye under visible and solar light on zinc oxide and nickel-doped zinc oxide thin films}, series = {Optical Materials}, volume = {151 (2024)}, journal = {Optical Materials}, publisher = {Elsevier}, issn = {1873-1252}, doi = {https://doi.org/10.1016/j.optmat.2024.115316}, pages = {1 -- 17}, abstract = {The kinetic investigation of rhodamine B dye's photocatalytic degradation, chosen as a model pollutant, was conducted at room temperature using Zinc oxide (ZnO) and nickel-doped zinc oxide (Zn0.97Ni0.03O) photocatalysts synthesized through the spray pyrolysis method. XRD analysis confirmed the formation of hexagonal ZnO and Zn0.97Ni0.03O films, with crystallite sizes ranging from 19 to 29 nm and varying in mean average grain size from 72 nm to 88 nm. The surface morphology of the Ni-doped ZnO films was influenced by nickel doping, observed through SEM and TEM micrographs, revealing a dense structure of spherical-shaped crystals. Light transmission and optical band gap energy of the films ranged between specified values, ranging from 3.27 to 3.24 eV. The degradation process was assessed under various conditions, including different light sources (UV lamp and solar irradiation), pH levels, and substrate concentrations. Degradation followed a pseudo-first-order kinetic model, with rate constants (k) and half-life times (t1/2) calculated accordingly. The degradation efficiency of undoped ZnO and ZnO doped with nickel decreased with increasing concentration under UV irradiation from (0.1-0.5 M) under UV irradiation decreased from (34.29-45.02) (49.61-56.61), while under visible light are (40-45.07 \%) (58.46-60.24 \%), removal rates ranged within specific percentages. The porous Zn0.97Ni0.03O synthesized at 0.5 M exhibited the highest photocatalytic efficiency due to its enhanced crystallinity, resulting in degradation rates of 9.22 and 11.22 × 10-3 min-1 and half-life times of 75.18 and 61.77 min at 90 min specified for both UV and solar light irradiations, respectively. Acidification of the reaction medium accelerated the photocatalytic degradation kinetics, while alkalization slowed it down. These findings mark a significant advancement in the utilization of oxide semiconductors for water pollutant degradation under natural sunlight.}, language = {en} } @misc{BoucharebFellahHeziletal., author = {Bouchareb, Nabila and Fellah, Mamoun and Hezil, Naouel and Hamadi, Fouzia and Montagne, Alex and Obrosov, Aleksei and Yadav, Krishna Kumar and El-Hiti, Gamal A.}, title = {Effect of milling time on structural, physical and photocatalytical properties of Ti-Ni alloy for biomedical applications}, series = {The International Journal of Advanced Manufacturing Technology}, volume = {131 (2024)}, journal = {The International Journal of Advanced Manufacturing Technology}, publisher = {Springer}, issn = {1433-3015}, doi = {https://doi.org/10.1007/s00170-024-13207-5}, pages = {3539 -- 3553}, abstract = {Ti-Ni shape memory alloys (SMA) are used extensively in the field of orthopedics owing to their unique physical and mechanical features, excellent corrosion resistance, and good biocompatibility in the human body environment. This study aims to investigate how milling time affects the characteristics of Ti-Ni alloys which were synthesized with equal atomic percentages by using a high-energy ball milling type (Planetary Micro Mill Pulverisette P7, Fritsch GmbH, Germany) under varying milling periods (2, 6, 12, and 18 h). The duration of the grinding process refines the grain and diminishes the material's porosity, improving the material's physical and structural characteristics as well as its photocatalytic activity. The milled powders of Ti50-Ni50 alloys underwent characterization employing scanning electron microscopy (SEM) associated with an energy dispersive spectrometer (EDS), X-ray diffraction (XRD), and spectrophotometery of visible and ultraviolet light (UV-VIS) to measure the solution absorbance of methylene blue (MB). The results revealed that the milling process influences the particle size and shape of powders, where the proportion of fine particles increased with increasing grinding times from 2 to 18 h due to severe deformation and fracturing. The crystallite size was reduced, and the microstrain increased, attaining values of 29 nm and 0.99\%, respectively. In addition, the pores of samples were decreased to 10 nm at higher milling times. Furthermore, solutions of MB containing powders of Ti50-Ni50 milled at 18 h exhibited good photocatalytic activity with a degradation rate value of 93.23\% after 60 min of irradiation time because of a greater surface area. The improved properties of Ti50-Ni50 alloys make them clinically useful for biomedical implantation in humans. Plus, they are considered to be effective materials for photocatalytic applications.}, language = {en} } @misc{BelgrouneAissaniAlhusseinetal., author = {Belgroune, Ahlam and Aissani, Linda and Alhussein, Akram and Zaabat, Mourad and Obrosov, Aleksei and Rtimi, Sami}, title = {In Vitro Corrosion and Wear Investigation of Multifunctional TiAlMoN Sputtered Coatings on Cold-Sprayed SS316L}, series = {ACS Applied Engineering Materials}, volume = {2}, journal = {ACS Applied Engineering Materials}, number = {2}, issn = {2771-9545}, doi = {https://doi.org/10.1021/acsaenm.3c00672}, pages = {345 -- 359}, abstract = {Although TiAlN has been thoroughly studied, there is still an ongoing demand for developing new-based TiAlN films with enhanced protection efficiency for a long lifetime and high load-bearing capability linked to friction and corrosion mechanisms. This work aims to present the effect of Mo content by studying the structural tribo-mechanical, wettability, and corrosion behaviors in TiAlMoN coatings deposited by magnetron sputtering on cold-sprayed stainless steel 316L substrates. TiAlMoN coatings showed a dense columnar structure with the coexistence of titanium and molybdenum nitrides, and TiN (200) preferred orientation changed to TiN(111) with increasing Mo content. The surface energy of the TiAlMoN coatings decreased gradually with the increase in Mo content. The TiAlMoN coating containing 16.09 atom \% Mo possesses the highest hardness and Young's modulus (29.5 and 334.5 GPa, respectively) and the maximum H/E and H3/E2 of 0.092 and 0.237, respectively. Formations of tribolayer oxides reduced the friction and enhanced the wear resistance of TiAlMoN coatings in atmospheric conditions and reached the minimum values of 0.3 and 0.849 × 10-6 mm3/N, respectively, at 16.09 atom \% of Mo under 5 N load charge. Corrosion examination in simulated seawater revealed that TiAlMoN coating-coated SS316L exhibited a significant positive shift of about -16 mV in corrosion potential with a notable reduction in corrosion current density (1.41 nA/cm2), confirming the improved corrosion performance. The combination of both cold spray and magnetron sputtering techniques for producing this kind of component is shown to have great potential in processing applications.}, language = {en} } @misc{FellahHezilBourasetal., author = {Fellah, Mamoun and Hezil, Naouel and Bouras, Dikra and Obrosov, Aleksei and Samad, Mohammed Abdul and Montagne, Alex and Abd-Elmonem, Assmaa and Din, Sayed M El and Weiß, Sabine}, title = {Structural, mechanical and tribological performance of a nano structured biomaterial Co-Cr-Mo alloy synthesized via mechanical alloying}, series = {Journal of Materials Research and Technology}, volume = {25}, journal = {Journal of Materials Research and Technology}, issn = {2214-0697}, doi = {10.1016/j.jmrt.2023.06.031}, pages = {2152 -- 2165}, abstract = {The influence of milling time on the tribological behavior of a Co-Cr-Mo alloy designed for biomedical applications, synthesized via mechanical alloying is investigated. Elemental Co, Cr and Mo powders are milled using different milling times (2, 6, 12 and 18 h) in a high-energy ball mill. The resulting powders were subjected to cold uniaxial and hot isostatic pressing respectively, followed by sintering to obtain cylindrical samples, which were evaluated for their structural, mechanical and the wear behavior. Results showed that the grain and crystallite sizes of the powders decreased with increasing milling time, reaching low values of <10 μm and 32 μm respectively, at higher milling times. Furthermore, the wear rates and the coefficients of friction were lower, at higher milling times due to high densities (96\%), and higher elasto-plastic resistance, as presented by the H/E and H3/E2 values of 0.026 and 0.0021 GPa, respectively. Increased milling time enables the refinement of grains and reduction in porosity in the Co-Cr-Mo alloy, which in turn increases the alloy's elasto-plastic resistance and enhances its wear resistance.}, language = {en} } @misc{CelikAtapekPolatetal., author = {{\c{C}}elik, G{\"u}l{\c{s}}ah Akta{\c{s}} and Atapek, Şaban Hakan and Polat, Şeyda and Obrosov, Aleksei and Weiß, Sabine}, title = {Nitriding Effect on the Tribological Performance of CrN-, AlTiN-, and CrN/AlTiN-Coated DIN 1.2367 Hot Work Tool Steel}, series = {Materials}, volume = {16}, journal = {Materials}, number = {7}, issn = {1996-1944}, doi = {10.3390/ma16072804}, abstract = {In this study, heat-treated and multisurface engineered DIN 1.2367 tool steel was subjected to room and elevated temperature wear tests, and the effect of nitriding on its tribological behavior was investigated. CrN, AlTiN, and CrN/AlTiN coatings with a total thickness of 2 µm were obtained by arc cathodic physical vapor deposition on conventional heat-treated and gas-nitrided steels. The white layer formed during nitriding was removed, and a diffusion layer (100 µm) was achieved in the cross section of the steel having a tempered martensitic matrix. The highest surface hardness was attained with an integral coating (CrN/AlTiN), and surface hardness increased even more after nitriding due to the formation of a multicomponent ceramic layer on top of the diffusion layer. The room temperature wear tests performed against an alumina counterpart revealed that (i) CrN/AlTiN-coated steel had the highest friction coefficient of 0.26, which further increased to 0.33 by nitriding due to the increase in shear strength, and that (ii) with increasing surface hardness, the specific wear rates (W) of the heat-treated and coated steels could be ranked as follows: WCrN/AlTiN < WAlTiN < WCrN. The wear rates decreased when nitriding was carried out prior to coating. In order to simulate the aluminum extrusion conditions, hot wear behavior of the surfaces against AA6080 alloy at 450 °C was investigated. The hot wear tests revealed that (i) high friction coefficients were reached due to the adhesive characteristic of aluminum to the surfaces, (ii) the nitrided and CrN/AlTiN-coated sample exhibited the lowest wear rate among all studied surfaces, and (iii) the film damage on the worn surfaces mostly occurred in the form of droplet delamination.}, language = {en} } @misc{DahmaniFellahHeziletal., author = {Dahmani, Marwa and Fellah, Mamoun and Hezil, Naouel and Benoudia, Mohamed-Cherif and Samad, Mohammed Abdul and Alburaikan, Alhanouf and Khalifa, Hamiden Abd El-Wahed and Obrosov, Aleksei}, title = {Structural and mechanical evaluation of a new Ti-Nb-Mo alloy produced by high-energy ball milling with variable milling time for biomedical applications}, series = {The International Journal of Advanced Manufacturing Technology}, volume = {129}, journal = {The International Journal of Advanced Manufacturing Technology}, number = {11-12}, issn = {1433-3015}, doi = {10.1007/s00170-023-12650-0}, pages = {4971 -- 4991}, abstract = {The main focus of this work is to investigate the impact of varying milling times (2 to 18 h) on the structural and mechanical properties of the developed Ti-Nb-Mo alloy. The morphology, phase composition, microstructure, and mechanical behavior of milled and sintered Ti-25Nb-25Mo alloy samples were characterized systematically using x-ray diffraction, scanning electron microscope, optical microscope, and Vicker microhardness. It was noted that the quantity of the β-Ti phase increased as the milling time increased. After 12 h of milling, the synthesized alloys exhibited a spherical morphology and texture with homogeneous distribution. The milled alloys' structural evolution and morphological changes were found to be dependent on their milling duration. Morphological analysis revealed that the crystallite size and mean pore size decreased when the milling duration increased, reaching minimum values of 51 nm and < 1 μm, after 12 and 18 h respectively. As the milling time increased, the grain size decreased, resulting in an increase in density, microhardness, and elastic modulus. Ti-25Nb-25Mo will presents good anti-wear ability and higher resistance to plastic deformation due to enhanced mechanical characteristics (H/E, and H3/E2). Hence, the developed Ti-25Nb-25Mo alloys with reduced elastic modulus and desirable mechanical properties were found to be a promising option for biomedical applications.}, language = {en} } @misc{FellahHezilBourasetal., author = {Fellah, Mamoun and Hezil, Naouel and Bouras, Dikra and Montagne, Alex and Obrosov, Aleksei and Jamshed, Wasim and Ibrahim, Rabha W. and Iqbal, Amjad and El Din, Sayed M. and Khalifa, Hamiden Abd El-Wahed}, title = {Investigating the effect of milling time on structural, mechanical and tribological properties of a nanostructured hiped alpha alumina for biomaterial applications}, series = {Arabian Journal of Chemistry}, volume = {16}, journal = {Arabian Journal of Chemistry}, number = {10}, issn = {1878-5379}, doi = {10.1016/j.arabjc.2023.105112}, abstract = {In this work was prepared α-Al2O3 alloys from laboratory aluminum oxide powder that was milled for different periods of time and sintered at a temperature of 1450 °C. The difference between the prepared samples was studied using several experimental measurement techniques, including X-ray diffraction, scanning electron microscopy and measurement of physical and mechanical properties. Moreover, the effect of milling time on the formation and sintering of alpha-alumina, by milling the mixture at different times using high energy crushing technique was studied. An influence of milling time on density, open spaces and microstructure of the samples was analyzed. The obtained results showed that longer milling duration led to alloys with higher hardness (H) and modulus of elasticity (E). This improvement is due to lower porosity and corresponding higher density at high temperatures. A noticeable decrease in the size of the particles with the increase of the milling time led to an increase in the lattice parameter accompanied by a decrease in defects and ionic voids. The percentage of pores reached 0.04 \% within 24 h of grinding after it was approximately 0.20 \%, while the density reached 96 \% after the same highest grinding time. Tests showed that the value of friction coefficient decreases, while it increases with the increase in the applied pressure force and this was confirmed by SEM images of the samples. the main factor to reduce friction is the increase in grinding time, regardless of the value of the applied load. The results showed that the Al2O3 alloy applied to it with a load of 2 N and milled for 24 h had a minimum value of 1.94 µm3 wear volumes and a wear rate of 1.33 (µm3∙N-1∙µm-1). The sample milled for 24 h showed the best result, characterized by the lowest wear size, specific wear rate and the highest hardness with extraordinary density of 96 \%, which is important in the field of biomaterials applications.}, language = {en} } @misc{BourasFellahBarilleetal., author = {Bouras, Dikra and Fellah, Mamoun and Barille, Regis and Weiß, Sabine and Samad, Mohammed Abdul and Alburaikan, Alhanouf and Khalifa, Hamiden Abd El-Wahed and Obrosov, Aleksei}, title = {Improvement of photocatalytic performance and sensitive ultraviolet photodetectors using AC-ZnO/ZC-Ag2O/AZ-CuO multilayers nanocomposite prepared by spin coating method}, series = {Journal of Science: Advanced Materials and Devices}, volume = {9}, journal = {Journal of Science: Advanced Materials and Devices}, number = {1}, issn = {2468-2179}, doi = {10.1016/j.jsamd.2023.100642}, abstract = {Morphological and optical properties of a multilayer film (CAZO/CZAO/ZACO) prepared by spin-coating method and deposited on a glass substrate were evaluated. The study was initially carried out for each layer, individually and then as a multilayer subsequently. Structural properties using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), infrared spectra (IR) and X-ray photoelectron Spectroscopy (XPS) showed the presence of three phases of zinc, copper and silver oxides at different levels. The CZAO sample observed with scanning electron microscope (SEM) showed an excellent porous surface with a large deformation in the multilayer configuration. Doping with zinc and copper in the silver crystal lattice improved the crystal structure and reduced the optical energy gap, thus increasing the optical absorbance and refractive index. The dielectric constants and showed an increase in the optical polarization values for lower photonic energies. The maximum degradation rate for photocatalysts of methylene blue was 89 \% for a 5-h exposure period with CAZO/CZAO/ZACO while it reached 71 \% for the CZAO sample during the same time period. The sensitivity of samples to light proved that the presence of ultraviolet radiation increases the number of holes trapped by oxygen ions and causes more free electrons and contribute to a better production of photocurrent than in darkness.}, language = {en} } @misc{HamadiFellahHeziletal., author = {Hamadi, Fouzia and Fellah, Mamoun and Hezil, Naouel and Bouras, Dikra and Laouini, Salah Eddine and Montagne, Alex and Khalifa, Hamiden Abd El-Wahed and Obrosov, Aleksei and El-Hiti, Gamal A. and Yadav, Krishna Kumar}, title = {Effect of milling time on structural, physical and tribological behavior of a newly developed Ti-Nb-Zr alloy for biomedical applications}, series = {Advanced Powder Technology}, volume = {35}, journal = {Advanced Powder Technology}, number = {1}, issn = {1568-5527}, doi = {https://doi.org/10.1016/j.apt.2023.104306}, abstract = {Titanium (Ti)-based alloys with only a β-phase have attracted academic and industrial interest for orthopedic application, due to their close properties to those of tissues. The current study aims to investigate the effect of milling time (2 h, 6 h, 12 h and 18 h) on the nanostructured ternary alloy Ti-25Nb-25Zr prepared by high energy milling, on its structural, physical and tribological behaviors. The alloys' characteristics such as relative density/porosity, surface roughness, were evaluated using XRD, SEM, surface profilometry, and microdurometer, respectively. The tribological characterization was done using an oscillating tribometer under wet conditions, simulating the human body environment. Results showed that the crystallite and mean pore size reduced with increasing milling time, with the smallest values of 26 nm and 40 µm, respectively after 18 h. Structural characterization shows that the amount of the β-Ti phase increased with increasing milling time, resulting in spherical morphology and texturing of the synthesized alloys. The milled alloys' structural evolution and morphological changes were sensitive to their milling times. Also, the relative density, Young's modulus and hardness, increased due to grain size decreased with increasing milling time. Tribological results showed that the effect of milling has a significant effect on both nanomaterial formation and friction-wear behavior of the alloys. The results showed that, friction coefficient and wear rate significantly decreased due to the increased formation of protective films such as TiO2, Nb2O5 and ZrO2 phases. The wear mechanism of the Ti-25Zr-25Nb system was dominated by abrasion wear accompanied by adhesion wear.}, language = {en} } @misc{DahmaniFellahHeziletal., author = {Dahmani, Marwa and Fellah, Mamoun and Hezil, Naouel and Benoudia, Mohamed-Cherif and Obrosov, Aleksei and El-Hiti, Gamal A. and Weiß, Sabine}, title = {Bioactivity and tribological performance of a novel nano-biomaterial beta-type Ti-alloy}, series = {Journal of materials research and technology}, volume = {36}, journal = {Journal of materials research and technology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2214-0697}, doi = {https://doi.org/10.1016/j.jmrt.2025.03.180}, pages = {2297 -- 2316}, abstract = {This study investigates the bioactivity; wear performance, and topography of a novel beta-type titanium-based alloy using techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and 2D and 3D analysis. The tribological test was evaluated using a ball-on-disk tribometer in a wet environment. Different loads of 2, 6, and 10 N were applied during the evolution. The data results indicate a significant effect of the milling process on the formation of the hydroxyapatite layer on the surfaces of the Ti-Nb-Mo alloy. Both the wear volume and rate showed a consistent trend of decrease as the milling time increased from 2 to 12 h for all applied loads. The minimum values of wear and volume were reached after 12 h of milling. The improvement in tribological behavior can be attributed to the improved mechanical properties of the alloys. In addition, the significant presence of niobium (Nb) and molybdenum (Mo) plays a critical role in achieving high coefficient of friction values. The primary wear mechanism observed in the Ti-25Nb-25Mo system was adhesive wear in addition to abrasive wear. With its lower Young's modulus and favorable biological and tribological properties, the Ti-25Nb-25Mo alloy represents a promising option for bone tissue applications in orthopedics.}, language = {en} } @misc{MorozovaObrosovNaumovetal., author = {Morozova, Iuliia and Obrosov, Aleksei and Naumov, Anton and Michailov, Vesselin and Doynov, Nikolay}, title = {Factors affecting mechanical properties of impulse friction stir welded AA2024-T351 under static and cyclic loads}, series = {Machines}, volume = {13}, journal = {Machines}, number = {6}, editor = {Markopoulos, Angelos P. and Astolfi, Davide}, publisher = {MDPI}, address = {Basel}, issn = {2075-1702}, doi = {10.3390/machines13060529}, pages = {1 -- 16}, abstract = {This study investigates the factors affecting the mechanical performance of conventional and impulse friction stir welded (FSW and IFSW) AA2024-T351 joints under static and cyclic loading. Emphasis is placed on the influence of fracture-inducing features such as oxide inclusions, constituent particle distributions, crystallographic texture, and precipitation state. A series of IFSW welds produced at varying impulse parameters were compared to conventional FSW welds in terms of microhardness, tensile strength, fatigue life, and Taylor factor distribution. IFSW joints demonstrated a significant improvement in tensile strength and elongation, particularly at higher impulse frequencies. Enhanced material mixing due to the reciprocating tool motion in IFSW resulted in finer particle distribution, more favorable crystallographic texture, and reduced weld pitch, all contributing to increased ductility and strength. Fractographic analyses revealed that fatigue failures primarily initiated in the stir zone, typically at unplasticized metallic inclusions. However, IFSW joints displayed longer fatigue lives, particularly when impulse parameters were optimized. These findings underline the complex interplay of microstructural and textural factors in determining weld performance, highlighting IFSW as a promising technique for enhancing the durability of high-strength aluminum welds.}, language = {en} }