Showing 408 results for Co
Marzieh Akbari, Fatemeh Dabbagh Kashani, Seyed Mohammad Mirkazemi,
Volume 22, Issue 4 (12-2025)
Abstract
CIGS solar cells are currently very high-efficiency thin-film solar cells. With regard to higher efficiency in solar cells, research is being conducted on the influence of both light scattering and plasmonic resonances due to metallic nano-structures. This article discusses the assessment of the incorporate plasmonic nanostructures on the absorber layer of a 1000 nm CIGS solar cell, in terms of light absorption and device performance. It is noted that decisions on material, size, and surface coverage (Occupied Factor) were important considerations that affected the performance. Opto-electrical assessment was used to investigate absorption, charge-carrier generation, current density-voltage response, power-voltage properties, and total efficiency. Using simulations, we discovered the aluminum nanosphere arrays (200 nm diameter, Occupied Factor 0.64) at the top of the absorber layer yielded the maximum efficiency (26.14%). This was shown by the resonances, and near-field distribution garnered from the nanospheres boost charge carrier generation, diminished recombination losses, and increased charge separation. Collectively, these raised the performance of the CIGS solar cells in this research and suggested hope for moving CIGS and potentially other photovoltaics forward using nanoscale plasmonic resonances.
Yasin Mehdizadeh, Saeed Reza Allahkaram, Mohammad H.mohammad-Ebrahimi, Majid Shamsarjmand,
Volume 22, Issue 4 (12-2025)
Abstract
The present work deals with the corrosion behavior and mechanical properties of a coted AZ31 magnesium alloy through plasma electrolyte oxidation (PEO) coating process in different alkaline electrolytes based on sodium silicate (Si-coating), sodium polyphosphate (P-coating) and sodium aluminate (Al-coating). The scanning electron microscopy (SEM) equipped with the energy dispersive x-ray spectroscopy (EDX) plus x-ray diffraction were recruited to investigate the morphology, chemical composition, and phase structure of coatings, respectively. Microscopic scrutiny revealed that the coating in the phosphate electrolyte was twice as thick and the relative porosity percentage was higher than those formed in the other electrolytes. The phase analysis indicated that the MgO was present as the prevailing phase in the Al-coating and P-coating. However, the dominant phase in the Si-coating was Mg2SiO4. Electrochemical testing was examined in a solution containing 3.5.wt% sodium chloride, showing improvements in corrosion resistance of coated alloys. These investigations confirmed that the corrosion resistance of Si-coating was dramatically higher than others which could be attributed to the presence of the dense and stable Mg2SiO4 phase as well as its relatively low porosity. According to the results of tensile tests, the coated samples had lower tensile strength and elongation than the uncoated one. The tensile strength and elongation diminished upon changing the electrolyte from Al-coating to P-coating, while the yield strength was almost similar. Further analyses indicated that the drop of tensile strength and elongation could be attributed to the presence of cracks and pores in the brittle ceramic PEO coating as stress concentration regions during deformation. Those areas are created due to thermal stress during the coating process and deformation in the elastic stage.
Vyacheslav Sirota, Sergey Savotchenko, Valeriya Strokova, Daniil Podgornyi, Marina Kovaleva,
Volume 22, Issue 4 (12-2025)
Abstract
The surface properties of metal-ceramic coatings based on titanium dioxide are described in dependence on the detonation spraying conditions. It is found that such properties as surface roughness, surface thickness and its hydrophobicity can be controlled in the production process by selecting certain values of the technological parameters of the spraying process. The optimal values of the technological parameters of detonation spraying, ensuring maximum hydrophobicity of the produced coatings are determined. The roughness of the coating surface and the coating thickness depend on the speed of the nozzle passage in accordance with the inverse power law. The roughness and the contact angle depend on spray distance in accordance with a parabolic law. New equations are obtained that can be useful for predicting the characteristics of the coating surface, as well as for determining the optimal mode of spraying the coating, ensuring its best hydrophobicity.
Behnam Lotfi,
Volume 22, Issue 4 (12-2025)
Abstract
Bulk titanium-based metallic glass with amorphous structure has led to the creation of special properties, which can be used as a suitable alternative to metallic biomaterials with crystalline structure. In the present study, bulk titanium-based metallic glass without Ni and Be elements produced by vacuum arc melting and cast into a 4 mm diameter mold. The evaluation of the results showed that the Ti50Zr15Cu20Mo7Ag4Sn3Si1 metallic glass has a composite structure of dispersed crystalline phases (α-Ti, β-Ti and Ti2Cu) in a glassy field. However, the Ti50Zr25Cu5Mo10Ag6Sn3Si1 alloy has a higher glass formation ability (GFA) and the crystalline phases formed in the Ti50Zr15Cu20Mo7Ag4Sn3Si1 alloy disappeared with increasing the amount of alloying elements Zr, Mo and Ag. The corrosion current (ICorr) of the Ti50Zr25Cu5Mo10Ag6Sn3Si1 alloy (43.28 nA) was lower compared to the corrosion current of the Ti50Zr15Cu20Mo7Ag4Sn3Si1 and Ti6Al4V samples (133.9 and 92.41 nA, respectively) in Hank's solution, hence the Ti50Zr25Cu5Mo10Ag6Sn3Si1 alloy showed better corrosion resistance.
Hajar Hussein, Mohammed Mohammed, Furat Al-Saymari,
Volume 22, Issue 4 (12-2025)
Abstract
Poly(2-aminobenzothiazole) (PAT) is a relatively new heterocyclic conducting polymer having a sulfur and nitrogen-rich chemical structure. During the past decade or so, there have been notable advances on the development of PAT. Especially, PAT and PAT-based composites have shown great potential for their applications in photovoltaic cells, solar cells and anti-corrosion organic coatings. In this study, 2-aminothiazole was successfully prepared as pure polymer and as composite materials with multi-wall carbon nanotubes (MWCNTs). FTIR, X-ray diffraction and SEM images were investigated, showing that the composite of poly 2-aminobenzothiazole: MWCNTs was successfully synthesized. The electrical features of the pure polymer and the composite thin films were examined. The findings show that the conductivity of the pure polymer and composite thin films are about 1.67x10-6 (S/cm) and 4.1x10-2 (S/cm), respectively, exhibiting a significant enhancement by a factor of 2.5x104 times as a results of doping the pure polymer by 1% wt MWCNTs.
Hossein Bayat, Parvaneh Sangpour, Mojgan Heydari, Leila Nikzad,
Volume 22, Issue 4 (12-2025)
Abstract
In this study, we investigated the antimicrobial, bioactivity, and in vitro cytotoxicity of a nanocomposite made of copper oxide (CuO) and aluminum oxide (Al2O3) with two different morphologies of copper oxide (Spherical-sCuO and Nanoplate-pCuO), which was made using the Spark Plasma Sintering (SPS) process on a titanium substrate as an orthopedic implant. Two different weight percents of copper oxide nanostructures of sCuO NP (10 wt%, 20 wt%) and pCuO NP (10 wt%, 20 wt%) have been used in this research. Synthesized nanocomposites were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscope (FESEM). Based on the obtained results, the XRD pattern and XPS confirmed that the nanocomposites were successfully synthesized without impurity. FESEM images showed that CuO nanoparticles and nanoplates were distributed on the alumina matrix homogeneously. The antibacterial activity of synthesized nanocomposites was investigated using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), gram-negative and gram-positive bacteria, respectively. Antibacterial activity results showed that CuO nanoparticles had high antibacterial activity, and the effect of CuO nanostuctures depended not only on their morphology and size, but also on the type of microorganisms. Furthermore nanocomposite with nanoplate copper oxide exhibited more bioactivity properties than the spherical shape. S. aureus showed greater resistance to CuO nanostructure, while E. coli was more susceptible to them (15%). In addition, toxicity tests showed that nanoplate copper oxide exhibited greater toxicity due to its high surface reactivity than spherical nanoparticles. This study provides new insights into the role of copper oxide nanoparticle morphology in the properties of nanocomposites for use as orthopedic implants.
Khashayar Zamani, Majid Tavoosi, Ali Ghasemi,
Volume 22, Issue 4 (12-2025)
Abstract
The present work, set out with the aim of studying the effect of in-situ precipitation of TiO2 form Ti3C2Tx MXene phase on the electromagnetic (EM) behavior of Ti3C2/TiO2 composites. In this regard, Ti3C2Tx MXene phase was synthesized using HF acidic etching of Ti3AlC2 MAX phase and the in-situ precipitation of TiO2 phase within Ti3C2 sheets was followed by controlled annealing in temperature range of 500-800 oC for 2 h. The phase and structural characteristics of prepared composites were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and differential thermal analysis. The electromagnetic behavior of samples was also analyzed using vector network analyzer (VNA). The results showed that by performing the controlled annealing process of Ti3C2Tx MXene phase, it is possible to in-situ formation of TiO2 phase and form the Ti3C2/TiO2 composites. The electromagnetic behavior of Ti3C2/TiO2 composites is in direct relation with the percentage of TiO2 phase deposited within Ti3C2 sheets during annealing process. The reflection loss (RL) changed from -7.98 to -21.28 dB (within frequency range of 1-18 GHz) with increasing in annealing temperature from 500 to 800 oC as well as increasing the size and percentage of formed TiO2 particles.
Yaser Vahidshad,
Volume 22, Issue 4 (12-2025)
Abstract
This work presents a comprehensive investigation of the high cycle fatigue behavior of Haynes 25 cobalt-based superalloy and its welds produced by pulsed continuous-wave (CW) laser welding. The alloy, manufactured through vacuum induction melting and electroslag remelting followed by rolling and annealing, exhibited a yield strength of 650 MPa, an ultimate tensile strength of 1050 MPa, and an outstanding elongation of 57% at room temperature. The fatigue limit was determined by test method as 200 MPa for lifetimes exceeding 10⁸ cycles, highlighting its excellent resistance to cyclic loading. For the weld zone, fabricated under optimized pulsed CW laser parameters, the yield and ultimate tensile strengths were 660 MPa and 965 MPa, respectively, with a fatigue limit of 175 MPa. Advanced microstructural analyses using OM, SEM, EBSD, and XRD revealed an austenitic FCC matrix with carbide precipitates, predominantly (W, Cr)₇C₃ and M₆C, decorating both the matrix and grain boundaries. Fatigue crack initiation in the base metal was associated with carbide clusters near the surface, while in the weld zone it was strongly linked to near-surface gas porosity defects. These findings not only establish fundamental fatigue benchmarks for Haynes 25 but also provide the first direct insights into the microstructural origins of fatigue damage in its laser-welded joints, thereby addressing a critical knowledge gap for its deployment in high-temperature and cyclic-loading environments.
