Bulletin of Materials Science最新文献

Austenitic stainless steel 316L (AISI 316L) is commonly employed in marine applications. However, this substrate is exposed to wear and corrosion conditions. To protect AISI 316L substrate from wear and corrosion attacks, it could be coated. In this study, diamond-like carbon (DLC) films were deposited on nitriding AISI 316L substrate. Then, the adhesion, hardness, wear and corrosion resistance of the DLC coated samples were studied. The coating was characterized by X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (RS) and field emission scanning electron microscopy (FESEM) and nano-indentation methods. Plasma nitriding treatment increased the adhesion of the DLC coating on the AISI 316L substrate. Electrochemical measurements and wear tests showed that deposition of the DLC coating improved corrosion and wear resistance of the AISI 316L substrate.

Chloride ions in the chemical, nuclear, pharmaceutical, food, marine, petrochemical industries, and body fluid medium cause pitting corrosion in stainless steel (SS). In this research, the pitting corrosion resistance behaviour of SS 304L was evaluated in simulated marine environment (SME) and simulated body fluid (SBF) solutions. A solution annealed coarse-grain (CG) SS 304L was severely plastic deformed (SPD, up to 90%) at liquid N₂ temperature. This leads to the formation of ultra-fine grain (UFG) microstructure. UFG specimens were further annealed at 1050°C for 1-h, and gamma-ray irradiated separately at a dose of 7 kGy. Pitting was evidenced for the as-received CG, UFG-deformed and UFG-deformed, followed by annealed (1050°C for 1 h) specimens, whereas pitting corrosion was not observed for the UFG specimen after gamma-ray irradiation in both SME and SBF solutions.

In this report, the structural, morphological and electro-optical analysis of 2-D graphitic carbon nitride (g-C₃N₄) nano-sheets has been performed. The g-C₃N₄ nano-sheets were synthesized based on the thermal calcination process and characterized by transmission electron microscopy (TEM). X-ray diffraction studies (XRD) showed the inter-layer spacing to be 0.323 nm for the (002) plane which is 3.5% more dense than crystalline graphite and higher than literature reports for g-C₃N₄. For the evaluation of electro-optical properties, we have utilized time-domain spectroscopy for the frequency range 0.2 to 2 THz. The complex reflective indices (n, k) and permittivity ((epsilon , epsilon {prime})) for g-C₃N₄ have been determined. The complex conductivity has been observed to increase monotonically with an increase in frequency. The mobility of g-C₃N₄ has been theoretically estimated. The terahertz band properties such as plasma frequency, damping rate (0.095 THz), and collision time, were calculated for the synthesized material. The high permittivity value for g-C₃N₄ as reported in this work is promising for THz frequency selective components such as resonators, absorbers and collimators.

In this paper, a bright, smooth and flexible tin coating on copper surface in methanesulfonic acid was prepared using polyoxyethylene-8-octylphenyl ether (Triton X-100) as surfactant, glutaraldehyde as auxiliary brightener and benzylacetone as brightener through electrodeposition technology, and its morphology, composition and adhesion were characterized by surface analysis techniques and bending tests. In addition, the electrochemical performance of plating solutions containing different additives and the resistance of tin coating to corrosion in a 3.5 wt.% NaCl solution were also investigated using electrochemical testings. The results showed that benzylacetone had stronger adsorption properties than glutaraldehyde, and could effectively suppress the growth of tin dendrites and improve the cathodic polarization ability of plating solutions. When combined, they exhibited higher binding energy on the tin (112) surface and had the highest adsorption stability, making the surface of tin coating smoother, more flexible and more corrosion resistant.

This study investigates the alternating current (AC) losses in pristine and MgB₂-added bulk Bi_1.8Pb_0.20Sr₂Ca₂Cu₃O_10+δ ((Bi, Pb)-2223) superconductors at 77 K. Polycrystalline pellets of (Bi, Pb)-2223 and 0.5, 1 and 2 wt.% MgB₂-added bulk (Bi, Pb)-2223 were synthesized using a solid-state reaction process. X-Ray diffraction (XRD) analysis confirms the presence of (Bi, Pb)-2223 as the primary phase in the crystal structure. Electrical resistivity measurements between 77 and 300 K reveals a decrease in the transition temperature (T_c) and an increase in the transition width (∆T_c) of (Bi, Pb)-2223 with increasing MgB₂ concentration. Diamagnetic response of the samples indicates a decrease in the superconducting volume fraction of (Bi, Pb)-2223 upon MgB₂ addition. Magnetic AC losses were measured as a function of applied magnetic field and frequency. The eddy loss contribution, estimated using the expression reported by Chattopadhyay and Dey [1,15,,2] has a measly contribution and hence confirms the dominant role of hysteresis loss in total magnetic AC losses.

The performance and stability of ITO/PEDOT:PSS Layer 2/P3HT: PCBM Layer 1/ZnO/interface/PEDOT:PSS Layer 1/P3HT: PCBM Layer 2/aluminium tandem organic solar cells are significantly influenced by the thermal annealing process. This study mainly focuses on how the annealing temperature changes the efficiency and overall performance of the solar cells. By systematically varying the working temperature, we investigate its impact on the electrical properties of the active layer, which directly correlates with the device’s photovoltaic performance. The results demonstrate that an optimal temperature improves the charge mobility and reduces recombination. These findings provide valuable insights into the thermal processing P3HT: PCBM tandem organic solar cells, offering a pathway to enhance their durability and practical viability for large-scale solar energy applications. By methodically varying the annealing temperature, we aim to understand the relationship between the temperature and key performance metrics, such as short-circuit current density (J_SC), open-circuit voltage (V_OC), fill factor (FF) and overall power conversion efficiency (PCE). V_OC and J_SC value decrease linearly with increasing temperature. Simulation results show that at 290 K, the device achieves its highest performance with a V_OC of 0.923 V, J_SC of −3.15 mA cm⁻², a fill factor of 39.3% and a PCE of 1.14%. This result paves the way for various opportunities to enhance the performance of P3HT: PCBM based organic solar cells.

In the present research work, SiC-based composite powders were successfully synthesized using the carbothermal reduction reaction (CTR) with high silica iron tailings (IOT) as raw materials; the anthracite culm was used as the carbon source. The effects of different sintering temperatures and carbon contents on the microstructure and phase composition of SiC powders were examined. The order of generation of reaction products during the synthesis of silicon carbide from IOT was also determined by thermodynamic analysis. The results revealed that as the CTR proceeded, the β-phase of SiC was synthesized when sintering was performed at 1500°C at a SiO₂/C molar ratio of 1:5.5 for 4 h, and the secondary crystal type was the Fe-Si compound. Thermodynamic studies showed that the presence of iron oxides in the IOT aided the synthesis of the SiC phase by CTR, a mineral phase with a high melting point, at a lower temperature. The present study thus provides significant guidance for the secondary utilization of IOT.

The elementary and critical process in dielectric capacitors is interfacial charge separation. In this work, we propose the synthesis and investigation of the optical, electrical and dielectric properties of a WO₃·H₂O/W₁₈O₄₉ heterojunction with optimized oxygen vacancies for efficient charge storage applications. Tungsten-oxide-based heterojunctions were synthesized via a co-precipitation method using varying HCl concentrations. XRD analysis confirmed the formation of distinct phases, while XPS and Raman spectra revealed effective charge transfer and structural defects. UV-DRS studies highlighted the formation of oxygen-deficient m-W₁₈O₄₉. Enhanced dielectric constant, low impedance and increased conductivity were observed, particularly with low HCl concentrations, due to improved interfacial charge separation in WO₃·H₂O/W₁₈O₄₉ heterojunction. These properties make the WO₃·H₂O/W₁₈O₄₉ heterojunction a promising candidate for energy storage applications, offering significant advantages such as improved cyclic stability, power density and reduced heat generation.

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This study investigates the enhancement of thermal stability and flame-retardant properties of textile materials through the incorporation of hydroxyapatite grafted with varying percentages of aminotrimethyl phosphonate (HAp–AMP). Using a MATHIS type SV manual coating machine, textiles were treated with different concentrations of AMP–HAp (2.5, 5, 10 and 20%) in a polyamide (PA) matrix. The mechanical properties, thermal stability and flame resistance of the treated fabrics were evaluated through standardized tests, including tensile strength and elongation measurements according to NF EN ISO 13934-1: 2013, thermogravimetric analysis, and flame tests per NF EN ISO 6940:2004–08. The results indicate significant improvements in the thermal and flame-retardant performance of the coated fabrics. Higher concentrations of AMP–HAp demonstrated superior resistance to thermal degradation and flame propagation, with the PA + 15 AMP–HAp sample showing the most robust performance. Scanning electron microscopy confirmed the formation of a uniform and dense coating layer, contributing to the enhanced properties. The study concludes that AMP–HAp coatings effectively improve the flame retardancy and durability of textiles, making them suitable for applications requiring high thermal and fire resistance.

To address the corrosion of mild steel in aggressive mine water environments, nickel-chromium-iron (Hastelloy^® G30), copper-nickel-tin (ToughMet^® 3), and cobalt-chromium-tungsten (Stellite^® 6B) alloys were evaluated for their corrosion resistance. The study examined their behaviour in synthetic mine water at pH levels 6, 3 and 1 using potentiodynamic polarisation, alongside microstructural, hardness, and X-ray diffraction (XRD) analyses. Hastelloy^® G30 had equiaxed γ grains with Cr₃C₂ precipitates, ToughMet^® 3 displayed large, irregular grains, and Stellite^® 6B showed γ grains with Cr₃C₂ at boundaries and twinning. Hastelloy^® G30 and Stellite^® 6B demonstrated active-passive transitions with localized corrosion, while ToughMet^® 3 showed pseudo-passivation with severe pitting across all pH levels. Hastelloy^® G30 achieved the lowest corrosion rates at pH 6 (0.63 ± 0.01 µm·y^–1) and pH 3 (0.74 ± 0.05 µm·y^–1) but performed poorly at pH 1 (7.75 ± 0.64 µm·y^–1), with a hardness of 180 ± 10 HV₂. Stellite^® 6B had low corrosion rates at pH 3 (1.32 ± 0.34 µm·y^–1) and pH 1 (5.61 ± 1.13 µm·y^–1), with a hardness of 368 ± 13 HV₂. ToughMet^® 3 showed high corrosion rates, particularly at pH 1 (118.78 ± 8.00 µm·y^–1). Stellite^® 6B is the most promising alternative for harsh mining environments, offering optimal hardness and corrosion resistance.