Papers by Mohammad Rezayat
Transactions of the Indian Institute of Metals
Journal of Composites Science
This study examines the synthesis and characterization of a copper–alumina nanocomposite powder. ... more This study examines the synthesis and characterization of a copper–alumina nanocomposite powder. Mechanical milling is employed to synthesize the powder, and a holistic analysis is conducted to evaluate its morphological and structural properties. TEM analysis reveals the presence of alumina particles within the copper matrix, indicating the formation of both coarse and fine particles at different stages of synthesis. XRD analysis demonstrates a reduction in copper’s crystallite size with increasing milling time, attributed to defects generated within the crystal lattice during milling. Additionally, statistical analysis is utilized to determine the significance of different factors influencing the synthesis process. ANOVA analysis reveals that milling time has a significant impact on the particle size of the nanocomposite powder, while temperature and their interaction do not exhibit significant effects. Optimization techniques are utilized to identify solutions that meet the speci...
Micromachines
The use of titanium and titanium-based alloys in the human body due to their resistance to corros... more The use of titanium and titanium-based alloys in the human body due to their resistance to corrosion, implant ology and dentistry has led to significant progress in promoting new technologies. Regarding their excellent mechanical, physical and biological performance, new titanium alloys with non-toxic elements and long-term performance in the human body are described today. The main compositions of Ti-based alloys and properties comparable to existing classical alloys (C.P. TI, Ti-6Al-4V, Co-Cr-Mo, etc.) are used for medical applications. The addition of non-toxic elements such as Mo, Cu, Si, Zr and Mn also provides benefits, such as reducing the modulus of elasticity, increasing corrosion resistance and improving biocompatibility. In the present study, when choosing Ti-9Mo alloy, aluminum and copper (Cu) elements were added to it. These two alloys were chosen because one element is considered a favorable element for the body (copper) and the other element is harmful to the body (al...
Metals
This study aimed to evaluate the corrosion properties of different samples coated by the laser-cl... more This study aimed to evaluate the corrosion properties of different samples coated by the laser-cladding method to find the optimal laser parameters. Thereby, potentiodynamic polarization (Tafel) and electrochemical impedance tests were performed to assess the corrosion resistance of coated samples. Consequently, the corrosion morphology of tested samples was inspected by scanning electron microscopy. The results demonstrated that the laser power directly correlates with pitting corrosion and defects on the surface of the samples. Moreover, when molybdenum and chromium ions are increased in the electrolyte solution, the passive and protective layers are more durable, as the ions are sited within the holes and defects, reducing the surface corrosion rate.
Results in Surfaces and Interfaces
Surface coating process is one of the techniques that increase the performance and service life o... more Surface coating process is one of the techniques that increase the performance and service life of parts by increasing the mechanical properties. In this study, compared to the layered coating, a composite coating was done by electroplating method on stainless steel grade st37. The aim of this study was to increase the mechanical properties of the surface base metal as well as the coating. Materials characterization tests such as X-ray diffraction tests and imaging were performed by scanning electron microscopy. In addition, a Vickers microhardness test and wear resistance were performed. Chemical tests were done on the created coating, the results of which were presented as polarization and Varna quest diagrams. According to the results, the coating containing Ni-Fe/Al2O3 particles showed better mechanical properties so that by increasing the amount of alumina particles to 50 g/L, the hardness reached 750 (HV 0.5), which is 585 (HV 0.5) for the coating without alumina was reported....
Plasma
In this study, the electrocatalytic activity of nickel foam, which is activated by cobalt, molybd... more In this study, the electrocatalytic activity of nickel foam, which is activated by cobalt, molybdenum, and nickel phosphide nanostructures, is prepared by the plasma hydrothermal method for use in the release of hydrogen and oxygen. The morphology and crystallographic structure of the synthesized phosphide specimens were examined by means of scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction. Moreover, the electrolysis activity for these sets of specimens was investigated using the Tafel polarization curve or linear sweep voltammetry, cyclic voltammetry, as well as by means of the electrochemical impedance spectroscopy technique. Preliminary results show that nickel phosphide presents the highest electrocatalytic activity than the other phosphides developed in this research. In this regard, it presents an electrocatalytic activity to release hydrogen and oxygen of around −1.7 and 0.82 mV, which is measured at a current density of 100 mA·cm−2...
Plasma, 2020
In this research, copper-tin alloy nanoparticles were made by a mechanical alloying method and we... more In this research, copper-tin alloy nanoparticles were made by a mechanical alloying method and were examined by two well-known and common bactericidal tests, optical density, and colony-forming units count in terms of bactericidal properties. To confirm the results, two different percentages were used as Sn-50Cu and Sn-83Cu, and standard amounts of these alloys were added to the Escherichia coli bacterial culture medium. The results of optical density show that with the addition of more values to the culture medium for bacteria, witnessing the destruction of bacteria, and also the results of colony counting tests can be seen that the number of colonies has decreased over time, even close to zero, which means the environment is free of bacteria. These standard values were different for both alloys; for the Sn-50Cu alloy, the maximum value was 4.5 mg, and for the Sn-83Cu alloy, it was 2.75 mg, which did not make any difference with the addition of these nanoparticles to the bacterial ...
Machines
Polyvinyl Alcohol (PVA) is frequently applied as a support material in 3D printing, especially in... more Polyvinyl Alcohol (PVA) is frequently applied as a support material in 3D printing, especially in the crafting of intricate designs and projecting elements. It functions as a water-soluble filament, often paired with materials like ABS or PLA. PVA serves as a momentary scaffold, supporting the jutting segments of a 3D model throughout the printing process. Subsequent to printing, the primary component can be effortlessly isolated by dissolving the PVA support using water. PVA, being a pliable and eco-friendly polymer, is susceptible to moisture. Its aqueous solubility renders it a prime selection for bolstering 3D print structures. In this investigation, equivalent-sized samples were 3D printed utilizing an Ultimaker 3D printer to assess the potency of PVA-generated specimens. Tensile examinations were executed on each sample employing a testing apparatus. The durability of the specimens was notably impacted by the input parameters, specifically the stratum width and stratum thickne...
Micromachines
The use of titanium and titanium-based alloys in the human body due to their resistance to corros... more The use of titanium and titanium-based alloys in the human body due to their resistance to corrosion, implant ology and dentistry has led to significant progress in promoting new technologies. Regarding their excellent mechanical, physical and biological performance, new titanium alloys with non-toxic elements and long-term performance in the human body are described today. The main compositions of Ti-based alloys and properties comparable to existing classical alloys (C.P. TI, Ti-6Al-4V, Co-Cr-Mo, etc.) are used for medical applications. The addition of non-toxic elements such as Mo, Cu, Si, Zr and Mn also provides benefits, such as reducing the modulus of elasticity, increasing corrosion resistance and improving biocompatibility. In the present study, when choosing Ti-9Mo alloy, aluminum and copper (Cu) elements were added to it. These two alloys were chosen because one element is considered a favorable element for the body (copper) and the other element is harmful to the body (al...
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Papers by Mohammad Rezayat