Materials Science Forum Vol. 1084

Abstract: In the present work, Zinc oxide Nanorods (ZnO NRs.) was prepared by using the chemical bath method and separating the resulting precipitate by centrifugation. The most important physical properties of nanorods such as optical, morphological and structural properties were diagnosed and studied by "X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), energy dispersive X-ray (EDX), as well as UV-visible spectroscopy". The results of XRD showed that the prepared material has a hexagonal crystal structure and is of high purity, as there are no peaks due to impurities. The formation of zinc oxide was also proven by means of EDX, the weight ratio of zinc and oxygen was 85% and 15%, respectively. The energy gap of prepared rods was equal 3.3 eV.

Abstract: The challenge in this research is the producing of nanoparticle superconductor compound. The benefit of nanoparticle is making the improving of the superconductor compound. The Bi₂Sr₂Ca₂Cu₃O₁₀ (Bi-2223) compound prepared by Co-precipitation method at different sintering temperatures (600, 700, 850 °C) (20 hrs) with pH value (7). The electric resistivity of samples measured under liquid helium closed cycle cryogenic system. The TEM estimation of sample prepared by Co-precipitation recognized the range of particles size is about (22 - 48nm) at sintering temperature (600 °C). The range of nanoparticles size is in about (65-112 nm) at sintering temperature (700 °C) and (80-124) nm at sintering temperatures (850°C). The critical temperature of sample at sintering temperatures (700, 850 °C) was about (109 ,112) K respectively The crystal structure confirmed by using X-ray diffraction, these peaks were found to be well indexed by the tetragonal phase of Bi-2223. It was defined the successful of this method is a function to presence of full properties for superconductor compound like Bi-2223 system. .

Abstract: Cerium oxide, also known as CeO₂, can be synthesized by the hydrothermal process with cerium nitrate precursor solution. After drying and sintering at 800,900, and 1100 C, different-sized cerium oxide nanoparticles were produced from the solution. Using x-ray diffractometers, the researchers were able to determine that all of the cerium oxide nanoparticles have a unique structure called fluorite crystalline structures. The structural, morphological and optical properties of films were investigated by a set of characterization techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM). The estimation of crystallite size is (22.12,27.34 and 42.02 nm), which is confirmed by Scherrer formulae from XRD pattern. The dielectric constant increased with the increase of crystallite size due to the size effect. The crystal size increased with increased sintering temperature. Keywords: Cerium oxide (CeO₂), structural, crystal size, , morphology,Dielectric constant.

Abstract: In this research, a homemade autoclave reactor was used for preparing iron oxide nanoparticles by hydrothermal technique at different reaction times by using ferric chloride, ferrous sulfate, and ammonium hydroxide as raw materials. The XRD characterization showed that the nanoparticles of the samples have high crystallinity with the crystal phase of magnetite, furthermore, the crystal phase of hematite appears clearly as the reaction time increased. The SEM results showed when the time of reaction increased the average particle size increased too from 28.1 to 49.2 nm. That means the reaction time is an effective parameter for the nanoparticle's growth, The EDX spectrum verified the confirmation of iron oxide nanoparticles by the appearance of Iron and Oxygen peaks. The FT-IR results showed that all samples have an absorption peak at about 578 cm^-1 corresponding to the Fe-O bond stretching modes of the in magnetite and the peak of hematite appeared as the reaction time increased above 2 hours which was confirmed with XRD results. Finally, the reaction time is a powerful tool for controlling in size and phase of nanoparticle preparation. Keywords: Hydrothermal, Iron Oxide, Reaction time, magnetite, and hematite.

Abstract: This study used Hibiscus sabdariffa flowers to prepare and characterise nickel oxide nanoparticles that are non-toxic and environmentally advantageous (green synthesis). After two hours of heat treatment at 600 °C, XRD was employed to validate the cubic crystal structure of NiO-NPs. The crystal plane (200) corresponded to the optimal peak on the XRD, With an average crystalline size, as per Williamson-Hall's formula, is 46.26 nm, while as per Scherrer's formula, it is 24.40 nm. At 524, 420, and 468 cm^-1, the FT-IR spectrum revealed a Ni-O vibration band. Throughout the surface microscopic analysis, Field-Emission Scanning Electron Microscopy (FE-SEM) revealed smooth, cylindrical rod-like crystals. As per the UV-Vis spectral curve, NiO-NPs had a direct bandgap (Eg) of 2.91 eV. NiO-NPs nanoparticles were shown to be more effective against gram-negative bacteria in terms of biological activities. P. aeruginosa was significantly more severely harmed than S. aureus.

Abstract: In this work, zinc nanoparticles were obtained. As a production method, a one-stage induction flow levitation method was used. The starting material was spherical granules with a purity of 99.9% and a mass of 2 g; as atoms evaporated from the surface of the molten granule, the drop was fed with a metal wire made of the same material. The productivity of the nanoparticles was 30 g / h. The resulting nanoparticles were characterized by scanning electron microscopy, X-ray phase analysis, porosimetry, and inductively coupled plasma atomic emission spectroscopy.

Abstract: The change in the coercive force of the 10kp5 steel specimens subjected to cyclic loading and impulse current has been studied. The choice of processing methods, including their combination in a certain sequence, was shown to provide the best plastic or strength properties of metal materials. The feasibility and good perspectives of express assessment of the effectiveness of the chosen method or methods of processing metal materials by magnetic properties, e.g., coercive force, without resorting to mechanical tests with the destruction of specimens, are noted. The highest changes towards increase in strength and coercive force in the 10kp5 low-carbon steel have been found after cyclic loading and in a combined mode with cyclic loading at the final stage. The optimal combination of cyclic loading and pulse current can make it possible to control the strength and magnetic properties of ferromagnetic materials.

Abstract: The methodology has been developed to show the functional connection of the impact strength of the heat-affected zone metal of welded joints with weld deposit thickness and, accordingly, with the consumption of welding materials during electric arc welding while constructing and repairing various metal structures and pipeline systems operating in conditions of low climatic temperatures. To reach the objective of the paper, rational intervals of cooling rates of the HAZ metal during welding low-alloy pipe steels were used, and the calculated dependences from the existing works were modified. The methodology allows increasing cold resistance of welded joints of steels of mass use by regulating the weld deposit thickness and welding consumables during electric arc welding while constructing and repairing various metal structures and pipeline systems operating in extreme conditions of the North.

Abstract: The properties of dampers manufactured by the selective laser melting are investigated. Microswear with different elastic and plastic properties were found. The texture of dampers samples represents a non-uniform supplement structure of crushed grains, separated by layers with dispersoids of crystallization of varying completion stages.