Materials最新文献

The production and use of Li-ion batteries (LIBs) is steadily increasing each year, leading to a growing number of battery-powered products. Consequently, the number of chemical hazards associated with the operation and other stages of the life cycle of this type of cell is increasing as well. Therefore, this study examined the impact of selected extinguishing agents for extinguishing Li-ion battery fires-namely, a dedicated extinguishing granulate, a natural sorbent (exfoliated vermiculite), and quartz sand-on the level of heat and released substances. The study determined the emission of heavy metals and polycyclic aromatic hydrocarbons (PAH) into the air during a cell fire, the concentration of the inhalable aerosol fraction, and the concentration of hazardous substances in the extinguishing agent residue. The analysis concluded that quartz sand provides the most effective heat removal and insulation of the battery from the external environment, which also reduces the amount of pollutants released into the environment.

This study presents a novel experimental methodology enabling the synchronous observation of strain and stress evolution in granular backfill subjected to active earth pressure. A physical model of plane deformation was used in which a rigid retaining wall was gradually moved away from the ground while simultaneously recording, at each step, both displacement-based images for digital image correlation (DIC) and photoelastic pictures of the force-chain rearrangements. The results show that active failure develops gradually through narrow shear bands, initiated near the wall base and propagating towards the ground surface. A consistent inverse relationship between shear-strain location and photoelastic stress concentration was identified: low-strain zones within the shear wedge in the shear and volumetric strain images correspond to strong force-chain development, whereas high-strain zones (strain localization) correspond to local stress release. These findings provide new experimental evidence regarding the micromechanics of active pressure and offer comparative data for calibrating DEM (discrete element method) models and interpreting the reduced active pressures reported in confined granular backfills.

A highly sensitive and fast procedure for the determination of trace germanium is presented. The carbon nanotubes/spherical glassy carbon electrode (CNTs/SGCE) has been applied for adsorptive stripping voltammetric determination of trace concentrations of Ge(IV) in solution, preceded by complexation with chloranilic acid. Carbon nanomaterials were used for the first time in the voltammetric determination of Ge(IV). The experimental variables such as supporting electrolyte concentration, chloranilic acid concentration, modification of the CNTs/SGCE by forming a bismuth film, and the potential and time for Ge(IV)-chloranilic acid adsorption, as well as instrumental variables on the germanium signal response, were tested. Under optimized conditions, the peak current was found to be proportional to the concentration of Ge(IV) over the range of 0.9 to 30 nmol L^-1 with R = 0.998. The detection limit, estimated from three times the standard deviation at low Ge(IV) concentration, was about 0.3 nmol L^-1. Possible interferences were evaluated. Finally, the proposed method was successfully applied for the determination of the total amount of germanium in drinking and river water samples.

WC-based cermet coatings with a CoCrNiAlTi binder were fabricated on 04Cr13Ni5Mo stainless steel substrates using the atmospheric high-velocity air-fuel (HVAF) spraying process. The influence of the air-to-fuel ratio (AFR) on the microstructure, mechanical properties, and wear resistance of the WC-CoCrNiAlTi coatings was systematically investigated. The results indicate that the WC-CoCrNiAlTi coatings primarily consisted of WC, (Co, Ni)₃W₃C and a face-centered cubic (FCC) binder phase. As the AFR increased, the formation of the (Co, Ni)₃W₃C phase gradually decreased. Concurrently, the coating density improved, which was attributed to the enhanced particle melting state and increased flight velocity, leading to better flattening upon impact. The average microhardness of the WC-CoCrNiAlTi coatings gradually increased with an increasing AFR. The coating produced at an AFR of 1.130 exhibited the highest microhardness of 1355.68 HV_0.2. Both the friction coefficient and the wear rate of the coatings decreased progressively as the AFR increased. At the optimal AFR of 1.130, the coating demonstrated the lowest friction coefficient (0.6435) and wear rate (1.15 × 10^-6 mm³·N^-1·m^-1), indicating a wear resistance 34.85 times that of the stainless steel substrate. Furthermore, the slurry erosion weight loss rate of the WC-CoCrNiAlTi coatings decreased gradually with increasing AFR. The coating sprayed at an AFR of 1.130 showed the minimum erosion rate (1.70 × 10^-6 g·cm^-2·min^-1), which was 24.04 times lower than that of the substrate. The erosion mechanism of the WC-CoCrNiAlTi coatings was identified as the fatigue-induced removal of WC particles under alternating stress. The ductile high-entropy alloy (HEA) binder effectively protects the brittle WC phase through adaptive deformation, thereby significantly mitigating coating damage.

This study evaluates an integrated approach for recovering lead and silver from lead cake through chlorination roasting followed by acid leaching. The lead cake originates from sulfuric acid leaching of zinc ferrite residues obtained during the hydrometallurgical processing of zinc calcine. The effects of roasting temperature, lead cake-to-NaCl mass ratio, and roasting duration on metal recovery were systematically examined to determine optimal process conditions. Based on the experimental results, roasting at 550 °C for 1.5 h with a lead cake-to-NaCl mass ratio of 1:3, followed by leaching in 1 M HCl, was selected as a representative and sufficiently effective condition for the combined process. Under these conditions, nearly complete dissolution of Pb and Ag was achieved, reducing their contents in the final solid residue to 0.90% and 0.0027%, respectively. Compared to direct chloride leaching, the combined process provided higher extraction efficiencies (Pb 98.67%, Ag 98.09%) and a lower final residue mass (34% vs. 45%). The roasting step enables the solid-state conversion of PbSO₄ into highly soluble chloride phases (PbCl₂ and Pb(OH)Cl), while ZnFe₂O₄, Fe₂O₃ and SiO₂ remain stable and form the inert matrix of the residue. Acid leaching at a lower solid-to-liquid ratio (1:10) ensures near-complete dissolution of Pb and Ag, whereas aqueous leaching at a high ratio (1:100) results in incomplete Pb removal. The compliance leaching test (EN 12457-2) confirmed that the residue produced after the optimized two-step treatment meets the EU criteria for inert waste. Overall, the proposed combined process enhances Pb and Ag recovery, minimizes environmental risk, and offers a technically robust and sustainable route for treating lead-containing industrial residues.

The use of activated carbon (AC) in environmental applications, particularly for water and air purification, is highly valued due to its excellent microstructural and adsorption properties. However, its powdered form presents significant challenges in industrial applications, such as difficulty in handling and potential environmental risks due to its tendency to disperse easily. To overcome these issues, converting activated carbon into a more industrially viable form, such as pellets, is crucial. In this study, pelletizing AC within a crosslinked polyvinyl alcohol-diglycidyl ether of bisphenol A (PVA-DGEBA) matrix enabled the production of structurally stable cylindrical pellets through the formation of a robust three-dimensional polymeric network. This approach required minimal binder usage and facilitated processing at relatively low temperatures, effectively overcoming common disintegration issues associated with traditional pelletization methods reliant on linear polymer binders and compression-based techniques. The resulting pellets exhibited methylene blue (MB) adsorption (q max ~14.8 mg/g of pellet), which is about 50% of the initial AC's adsorption capability, and retained structural integrity across multiple aqueous cycles. They also remained stable in methanol, ethanol and acetone by showing no observable disintegration, which highlights their excellent stability. Comprehensive characterizations, including hardness tests, swelling behavior, and various structural evaluations, revealed a mechanical strength of 3.37 ± 0.46 MPa and an adsorption volume of ~250 cm³/g through Brunauer-Emmett-Teller analysis, confirming effective crosslinking and the adsorption capabilities of the pellets. This eco-friendly and stable pelletization strategy demonstrated great potential for low-temperature pelletizing of AC, ensuring advanced applications in wastewater treatment even under pressurized conditions, presenting a significant improvement over the traditional method.

Ancient bronzes are invaluable for studying the cultures and history of ancient societies around the world. However, corrosion can diminish their research and aesthetic value, as well as affect their longevity. Therefore, it is crucial to study the corrosion behavior and mechanisms of these artifacts using advanced characterization techniques. This article provides a systematic review of the corrosion behavior of bronze artifacts and the advanced characterization techniques employed in their study. It summarizes the corrosion mechanisms of bronze artifacts and the factors affecting corrosion, including composition, structure, and the external environment. It also describes advanced analytical techniques for characterizing corrosion products and mechanisms, such as X-ray fluorescence (XRF), laser ablation coupled to quadrupole mass spectrometry (LAMQS), X-ray tomography (CT), and neutron diffraction. Bronze corrosion studies can be enhanced by the integration of artificial intelligence (AI) and machine learning (ML). Finally, it discusses potential future research directions in the field of bronze artifact corrosion and conservation.

The widespread application of Rhodamine B (RhB) poses a serious threat to the aquatic environment. ZnFe₂O₄, as a catalyst material, can effectively activate persulfate (PMS) and respond to visible light, thus effectively degrading RhB with the joint assistance of sunlight and PMS. This study recovered Fe₂O₃ from high-iron coal gangue through an activating-acid leaching-extracting-back-extracting process and synthesized ZnFe₂O₄ catalysts (CG-ZFO) using coal gangue back-extraction liquid as the Fe source by a hydrothermal method and cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal method. The characterization results of X-ray diffraction (XRD), scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS) showed that the CG-ZFO has a pure crystal phase, and the addition of CTAB can effectively improve the photoelectric performance of the catalyst. The synthesized CG-ZFO can produce a significant synergistic effect with simulated sunlight (SS) and PMS, and the constructed SS/CG-ZFO/PMS system had a good degradation effect on RhB. Based on the conclusions of free radical-quenching experiments, electron paramagnetic resonance (EPR) spectroscopy, and X-ray photoelectron spectroscopy (XPS), the main active species in the SS/CG-ZFO/PMS system was identified as ₁O², and the degradation mechanism of RhB was elucidated. CG-ZFO prepared from coal gangue holds promising potential for application in the remediation of organic dye wastewater, and this study also provides a new approach for the resource regeneration of high-iron coal gangue.

In this paper, a series of iron thin films were prepared using the direct current magnetron sputtering method at different deposition times. By means of characterization techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), and vibrating sample magnetometer (VSM), the structure, surface morphology, and magnetic properties of the iron thin films prepared at different deposition times were systematically investigated. The XRD results indicate that all the iron thin films exhibit a polycrystalline body-centered cubic structure, with an obvious preferred orientation in the (110) direction. As the deposition time increases, the average grain size of the iron thin films gradually increases. This is mainly because the post-sputtered atoms can provide the energy required for the formation, movement, and growth of the already deposited grains or clusters. When the deposition time is too long, factors such as elastic effects and size constraints will limit the growth of grains and clusters. Therefore, for the thin films deposited after 120 s, the average grain size gradually stabilizes. When the deposition time is short, the thin films usually grow in the form of island-like accumulation. Grains and clusters of uneven sizes accumulate on the substrate, so the roughness gradually increases. This also implies an increase in the density of defects such as internal stress and vacancies within the thin film. As the deposition time increases, the thin films gradually transform to grow in a layered and flat manner, and the grain size gradually stabilizes and becomes relatively uniform. Therefore, the roughness of the thin film samples decreases and tends to be stable. The magnetic property test results show that all the iron thin films exhibit ferromagnetism. The iron thin film prepared at a deposition time of 120 s has the best comprehensive performance, with a saturation magnetization M_s of 1567 emu/cm³, a coercivity of 92 Oe, and a remanence ratio of 0.86.

The structure and properties of coke are of significant importance in the metallurgical industry. Coke samples were prepared from different bituminous coals at varying temperatures using a one-sided heating furnace. The evolution of carbon structure during the coking process was investigated by X-ray diffraction (XRD) and Raman spectroscopy. The correlations between carbon structure parameters and the properties of the coal and coke were investigated during coke formation. The results indicated that with increasing temperature, the values of L_a, L_c, N, n, and f_a were increased, while the d₀₀₂ values decreased. The L_a/L_c ratio was expanded twice more than raw coal due to condensation and cross-linking reactions, indicating compaction of the carbon structure and the formation of larger aromatic units. A negative correlation was observed between L_c and the Coke Reactivity Index (CRI), whereas a positive correlation was found between L_a and Coke Strength after Reaction (CSR), which mean that coke properties improve with increasing L_c. Specifically, when L_c exceeds 2.4 nm, and L_a lies between 5 and 5.5 nm, the coke exhibits higher quality. The quality of coke is strongly affected by the structural evolution of carbon during the coal coking process.