Showing 128 results for Tin
Mehdi Mehranian, Hajar Ahmadimoghadam,
Volume 21, Issue 4 (12-2024)
Abstract
In this research study, a composite coating of Ni-Co/SiC-CeO2 was prepared on a copper substrate using the pulse electrodeposition technique. The effects of electrodeposition parameters, including current density, duty cycle, and frequency, on the properties of the prepared coating were investigated. The selected current density values were 0.1, 0.2, and 0.3 A/cm2, the duty cycle options were 10, 20, and 30%, and the frequency values were 10, 100, and 1000 Hz. Increasing the current density enhanced the microhardness of the coating but reduced its corrosion resistance. This behavior can be attributed to the grain refinement occurring within the coating as the current density increases. On the other hand, an increase in duty cycle resulted in a decrease in microhardness, which can be attributed to a decrease in the concentration of nanoparticles within the coating. The lower corrosion resistance observed at higher duty cycles could be attributed to the decrease in off-time, causing the pulse electrodeposition conditions to approach a DC (direct current) state. Furthermore, higher frequencies were found to be associated with increased microhardness and improved corrosion resistance of the coatings. The coatings with the highest corrosion resistance exhibited a corrosion current density of 0.29 µA/cm2 and a polarization resistance of 1063 Ω.cm2 in a 3.5% NaCl solution. These coatings were prepared using a current density of 0.2 A/cm2, a duty cycle of 10%, and a frequency of 1000 Hz.
Mohammad Derakhshani, Saeed Rastegari, Ali Ghaffarinejad,
Volume 22, Issue 1 (3-2025)
Abstract
In this research, the morphology of the Ni-W coating was modified by adding graphene oxide (GO) nanosheets in such a way that a foam-like structure with high porosity and holes in the form of intertwined tunnels was obtained. Different amounts of GO nanosheets were added to the plating bath and the resulting coating was examined. In order to estimate the electrochemically active surface area, the cyclic voltammetry (CV) test was used. Moreover, the linear polarization test (LSV) and chronoamperometry in 1 M NaOH were conducted to investigate the electrocatalytic activity for the hydrogen evolution reaction (HER). It was found that by adding 0.4 g/L GO to the electroplating bath, the electrocatalytic properties are doubled and the active surface of the electrode is significantly increased.
Ali Keramatian, Mohammad Hossein Enayati, Fatemehsadat Sayyedan, Sima Torkian,
Volume 22, Issue 2 (6-2025)
Abstract
The aim of this study was to investigate the effect of current density on the microstructure of electrodeposited Ni–WC–TiC composite coatings on 304 stainless steel and compare the corrosion resistance of the coating and substrate in a 3.5 wt.% sodium chloride solution. A Watts nickel bath was employed under direct current (DC) conditions. Microstructure, elemental composition, and phase composition analyses were conducted using scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results revealed that the coating formed at a current density of 40 mA/cm² exhibited a denser microstructure with higher cohesion and uniformity compared to coatings produced at other current densities. The corrosion resistance of the coating and substrate was evaluated using Tafel and electrochemical impedance spectroscopy (EIS) analyses. The corrosion test results indicated that the substrate exhibited superior corrosion resistance compared to the coating. Based on the dynamic polarization test plots, the corrosion mechanism of the substrate is active-quasi passive, with a pseudo-passive layer forming on the sample which remains stable within the potential range of -0.17 to 0.17 V. Beyond this potential range, the sample becomes susceptible to pitting. In the coated sample, the corrosion behavior is similar to that of the substrate, with the exception that the pseudo-passive layer remains stable within a narrower potential range of -0.19 to 0.08 V.
Seyed Ehsan Khadempir, Behnam Lotfi, Zohreh Sadeghian,
Volume 22, Issue 3 (9-2025)
Abstract
Ni-B4C nanocomposite coatings were deposited onto a pure Cu substrate using electroplating. Different types of current, including direct current (DC), pulse reverse current (PRC), and unipolar pulse current (PC), were applied using various concentrations of micron and nano size particles in the electroplating bath. Microstructure, hardness, and wear and corrosion behavior of the coatings were investigated. Microstructural evaluations were performed using scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM). Microhardness, pin-on-disk sliding wear, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) tests were conducted on the coatings. Electrodeposition using PRC resulted in a more uniform distribution of co-deposited B4C microparticles and nanoparticles within the coatings. Nanocomposite coatings reinforced with B4C nanoparticles were obtained using PRC with a bath concentration of 8 g/l, exhibited higher hardness and improved wear properties compared to composite coatings containing B4C micron-sized particles. Moreover, using PRC resulted in higher hardness values and improved wear and corrosion resistance compared to PC and DC.
Sara Ahmadi, Bijan Eftekhari Yekta, Alireza Mirhabibi,
Volume 22, Issue 3 (9-2025)
Abstract
The crystallization behavior and photocatalytic properties of the sol-gel derived glass ceramic coatings in the TiO2-SiO2-B2O3 system were studied. the prepared sol was sprayed on a glazed ceramic wall. Following drying, the coated specimens were fired at 900°C for 1 h. The impact of boron oxide content in the composition was explored in terms of anatase stability and glass maturing temperature. The thermal and crystallization behaviors of the dried gels were studied by the STA, XRD, and FESEM. The photocatalytic property of the coated layer was examined using methylen blue degradation. Based on the results, the sample containing 15 wt% of boron oxide demonestrated about 30% dye removal efficiency, after only 60 min of UV-irradiation. Additionally, this particular sample exhibited the greatest magnitude of the anatase phase in comparison to the other samples.
Yaser Vahidshad, Karen Abrinia,
Volume 22, Issue 3 (9-2025)
Abstract
Selective laser melting (SLM) is a widely used additive manufacturing method for 3D-printing metal parts. This study investigates how SLM parameters affect the density, microstructure, and mechanical properties of maraging steel 300. A process window was developed, revealing that maximum density and minimal porosity are achieved when laser energy density exceeds 50 J/mm³. Optimal parameters—100 mm/s scan speed, 20 μm layer thickness, 0.15 mm hatch distance, Stripe scanning strategy, and XZ build direction—were identified. Optimal processing reduced porosity, increased martensite content, and enhanced strength, reaching 1064 MPa and improving by 75% to 1862 MPa after aging and solution treatment. Strength gains were attributed to the uniform dispersion of nano-sized precipitates (such as Ni(Mo)3 and Ni(Ti, Al)3) within the martensitic matrix. Additionally, it was found that higher cooling rates further improve the mechanical strength of heat-treated parts.
Farhood Heydari, Seyed Mohammad Mirkazemi, Bijan Eftekhari Yekta, Seyyed Salman Seyyed Afghahi,
Volume 22, Issue 3 (9-2025)
Abstract
This study systematically investigates the crystallization behavior, phase evolution, and dielectric properties of a BaO-Al₂O₃-SiO₂ glass system modified with 10 wt% TiO₂. Thermal characterization revealed that TiO₂ addition notably reduced the glass transition temperature (from 781.6°C to 779.4°C) and softening point (from 838°C to 824.8°C) compared to the TiO₂-free glass, consequently decreasing the calculated nucleation temperature (from 810°C to 800°C). While differential thermal analysis indicated sluggish crystallization kinetics, isothermal heat treatments identified 1000°C as the optimal processing temperature, leading to the development of a multiphase crystalline assemblage that beneficially included the target monoclinic Ba3.75Al7.5Si8.5O32 phase, which was absent in the TiO₂-free glass. X-ray diffraction identified this phase, along with celsian (BaAl₂Si₂O8) polymorphs and barium titanate crystallites, as the dominant crystalline phases. SEM revealed anisotropic crystal growth (1.14-1.52 μm length). Dielectric characterization in the Ku-band (12.4-18 GHz) demonstrated significant property enhancements, with the relative permittivity decreasing from 10.40 to 6.38 and loss tangent improving from 0.3 to 0.2 after crystallization. These improvements, attributed to the specifically tailored crystalline phase assemblage facilitated by TiO₂, make this glass-ceramic system particularly suitable for advanced microwave applications requiring low dielectric loss and high-frequency stability. The effectiveness of TiO₂ as a crystallization modifier for achieving optimized dielectric properties through controlled devitrification and targeted phase formation is underscored.
Ali Azari Beni, Saeed Rastegari,
Volume 22, Issue 3 (9-2025)
Abstract
Aluminide coatings are widely used in high-temperature applications due to their excellent corrosion resistance and thermal stability. However, optimizing their composition and thickness is crucial for enhancing performance under varying operational conditions. This study investigates the optimization of aluminide coatings through a data-driven approach, aiming to predict the coating thickness based on various composition and process parameters. A comparative analysis of six machine learning models was conducted, with the k-nearest neighbors regressor (KNNR) demonstrating the highest predictive accuracy, yielding a coefficient of determination R² of 0.78, a root mean square error (RMSE) of 18.02 µm, and mean absolute error (MAE) of 14.42. The study incorporates SHAP (Shapley Additive Explanations) analysis to identify the most influential factors in coating thickness prediction. The results indicate that aluminum content (Al), ammonium chloride content (NH4Cl), and silicon content (Si) significantly impact the coating thickness, with higher Al and Si concentrations leading to thicker coatings. Zirconia (ZrO2) content was found to decrease thickness due to competitive reactions that hinder Al deposition. Furthermore, the level of activity in the aluminizing process plays a crucial role, with high-activity processes yielding thicker coatings due to faster Al diffusion. The pack cementation method, in particular, produced the thickest coatings, followed by gas-phase and out-of-pack methods. These findings emphasize the importance of optimizing composition and processing conditions to achieve durable, high-performance aluminide coatings for high-temperature applications.
