@misc{FellahHezilBourasetal., author = {Fellah, Mamoun and Hezil, Naouel and Bouras, Dikra and Bouchareb, Nabila and Larios, Alejandro Perez and Obrosov, Aleksei and El-Hiti, Gamal A. and Weiß, Sabine}, title = {Investigating the effect of Zr content on electrochemical and tribological properties of newly developed near β-type Ti-alloys (Ti-25Nb-xZr) for biomedical applications}, series = {Journal of Science: Advanced Materials and Devices}, journal = {Journal of Science: Advanced Materials and Devices}, issn = {2468-2179}, doi = {10.1016/j.jsamd.2024.100695}, abstract = {In order to create alloys with exceptional properties for orthopedic uses, this study focuses on the impact of zirconium (Zr) content on the structural, electrochemical, and tribological qualities of nanostructured Ti-25Nb-xZr [x = 5, 10, 15, 20, 25, and 30 atomic (at.) \%] alloys. The structural evolution was investigated using XRD and SEM techniques. The mechanical characteristics of the produced alloys, including Vickers hardness and Young's modulus, were measured. In addition, the corrosion tests were performed using the OCP, EIS, and PD methods in Ringer's solution within the independent pH range at 37 °C. A ball-on-disc tribometer was used to investigate the tribological behavior of the alloys under various loads and wet conditions using the Ringer solution. It has been verified that Zr content (at. \%) in the alloys had an impact on their morphologies, structural evolution, and mechanical characteristics. According to the morphological analysis, the particle and crystallite size decreases with increasing Zr content. Young's modulus and Vickers hardness show the same tendency. The EIS data demonstrated that a single passive film formed on the alloy surfaces, and the addition of Zr enhanced the corrosion resistance of the passive films. The polarization curves demonstrate that the alloys had low corrosion current densities and large passive areas without the passive films disintegrating. Likewise, the inclusion of Zr resulted in a reduction in the corrosion and passive current densities values. All of these results suggested that the titanium alloys exhibit a more noble electrochemical activity caused by Zr. From the tribological perspective, it was found that the friction coefficient of the alloys reduced with increasing Zr content.}, 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{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} }