Search Results (1,226)

The AZ31 magnesium alloy is an attractive lightweight metallic material, but its low corrosion resistance and wear resistance significantly limit its widespread application in fields such as aerospace, the automotive industry, and mechanical engineering. Moreover, most coating systems currently cannot restore their original functions and dimensions after localized damage. Based on this, this study combined cold spray (CS), micro-arc oxidation (MAO), and magnetron sputtering (MS) to develop a high-performance and repairable composite modification strategy. First, a 5056 aluminum alloy coating was prepared on AZ31 via CS, followed by the growth of a hard alumina (Al₂O₃) coating via MAO and a diamond-like carbon (DLC) coating via MS on the 5056 aluminum alloy surface. The microstructure, phase composition, hardness, tribological properties, and electrochemical corrosion behavior of the coatings were evaluated using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), X-ray diffraction (XRD), Vickers hardness testing, ball-on-disk dry sliding wear testing, and potentiodynamic polarization testing in a 3.5% sodium chloride solution. The CS 5056 aluminum alloy coating reduced the corrosion current density of AZ31 from 4.098 × 10⁻⁵ A/cm² to 2.714 × 10⁻⁶ A/cm². The MAO alumina coating increased the hardness of AZ31 from 68.60 HV_0.05 to 1614.00 HV_0.05 and decreased the wear rate from 1.703 × 10⁶ μm³/(N·m) to 2.038 × 10³ μm³/(N·m). The DLC coating further reduced the average coefficient of friction of the alumina coating from 0.48 to 0.27, decreased the wear rate to 6.979 × 10² μm³/(N·m), and lowered the corrosion current density from 3.020 × 10⁻⁶ A/cm² to 8.860 × 10⁻⁹ A/cm². This indicates that the three-phase composite coating achieves synergistic improvements in the corrosion and wear resistance of AZ31 through complementary advantages. Additionally, the thick CS aluminum alloy underlayer provides potential repairability, enabling the restoration of function and dimensions after damage without compromising the magnesium substrate. Overall, the proposed 5056Al/Al₂O₃/DLC composite coating strategy offers a reliable protective approach for AZ31 components and is expected to further expand their application fields. Full article

Crop production in the desert Southwest of the United States, as well as in other arid and semi-arid regions, requires tools that provide accurate crop evapotranspiration (ET) estimates to support efficient irrigation management. Such tools include the web-based OpenET platform, which provides real-time ET data generated from six satellite-based models, their Ensemble, and a field-based system (LI-710, LI-COR Inc., Lincoln, NE, USA). This study evaluated simulated ET (ET_SIM) of cotton (Gossypium hirsutum L.) derived from OpenET models (ALEXI/DisALEXI, eeMETRIC, geeSEBAL, PT-JPL, SIMS, and SSEBop), their Ensemble approach, and LI-710. Field data were utilized to estimate cotton ET using the soil water balance (SWB) method (ET_SWB) from June to October 2025 in Gila Bend, AZ, USA. Four evaluation metrics, the normalized root-mean-squared error (NRMSE), mean bias error (MBE), simulation error (S_e), and coefficient of determination (R²), were employed to evaluate the performance of OpenET models, their Ensemble, and the LI-710 in estimating cotton ET. Statistical analysis indicated that the ALEXI/DisALEXI, geeSEBAL, and PT-JPL models substantially underestimated ET_SWB, with simulation errors ranging from −26.92% to −20.57%. The eeMETRIC, SIMS, SSEBop, and Ensemble provided acceptable ET estimates (22.57% ≤ NRMSE ≤ 29.85%, −0.36 mm. day⁻¹ ≤ MBE ≤ 0.16 mm. day⁻¹, −7.58% ≤ S_e ≤ 3.42%, 0.57 ≤ R² ≤ 0.74). Meanwhile, LI-710 simulated cotton ET acceptably with a slight tendency to overestimate daily ET by 0.21 mm. A strong positive correlation was observed between daily ET_SIM from LI-710 and ET_SWB, with S_e and NRMSE of 4.40% and 23.68%, respectively. Based on our findings, using a singular OpenET model, such as eeMETRIC, SIMS, or SSEBop, the OpenET Ensemble, and the LI-710 can offer growers and decision-makers reliable guidance for efficient irrigation management of late-planted cotton in arid and semi-arid climates. Full article

The Phoenix Metropolitan Area (PMA) is situated in the Sonoran Desert of Central Arizona, USA. The PMA is a focus of ongoing climate change and urban heat island research. This paper addresses differences in the receipt of shortwave irradiance (global radiation) between the city and its surroundings. Several weather networks (e.g., AZ Met, an Arizona agricultural network) and air quality monitoring sites allow for the determination of shortwave irradiance between urban and rural locales, as well as a preliminary relation to seasonal patterns of suspended particulates. Particulate matter 10 μm and smaller (PM10) ranges from ca. 10 µg/m³ to 30 µg/m³ from winter to summer in rural areas, whereas in the metropolitan area, PM10 often exceeds 40 µg/m³ year-round. On average, urban transmissivity (T) of shortwave irradiance is lower than rural values by 1% in summer to over 5% in winter, like other urban studies evaluating effects on irradiance. Percentage differences between a site on a local mountain and the valley floor (about 400 m difference) range from 1% in summer to 5% in winter, in sync with seasonal mixing height changes and vertical mixing of particulates. Full article

This study examined cast AZ31 magnesium alloy and its variant containing micro-alloying elements of Y and Ca (AZXW alloy), evaluating their potential as anode materials in magnesium–air batteries. The AZXW alloy was fabricated via two manufacturing techniques: casting and extrusion. The synergistic influence of Y and Ca, in conjunction with the production procedure, on the microstructure, electrochemical characteristics, and anodic discharge behavior of the examined alloys was investigated. The addition of Y and Ca results in the formation of secondary phases that affect grain size, particle size, and distribution, as well as the electrochemical performance and discharge properties of the Mg–air battery constructed for this study, over 24 h or until fully discharged. This work demonstrates the potential to enhance discharge performance and electrochemical behavior by adjusting the aqueous electrolyte solution in the battery through the incorporation of Citric Acid (C.A) at varying concentrations. The incorporation of citric acid into the aqueous electrolyte improves battery stability and specific energy as long as citric acid is present in the solution. Magnesium hydroxide (Mg(OH)₂) begins to form on the anode surface as its concentration progressively decreases due to complexation with dissolved magnesium ions. This diminishes the effective anode area over time, ultimately resulting in the distinctive “knee-type” collapse characteristic of electrolytes containing citric acid. Full article

Polyhydroxybutyrate (PHB) is considered a coating material capable of limiting the corrosion of biodegradable metallic implants due to its biocompatibility and ability to form a physical barrier. In this study, PHB was deposited on commercial AZ91D magnesium alloy using the spin coating technique. To improve adhesion at the polymer–substrate interface, the magnesium substrates were subjected to atmospheric pressure plasma treatment for different exposure times (5, 10, or 15 min) before coating. The optimal treatment time of 5 min significantly increased substrate wettability and surface free energy, facilitating stronger PHB adhesion. In addition, the PHB coatings were subjected to atmospheric pressure plasma treatment for 5, 10, or 15 s to evaluate potential surface modifications. Corrosion behavior under simulated physiological conditions was assessed via potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in HANK’s solution at 37 °C. Pull-off tests were used to evaluate the adhesion strength between the coating and the substrate under each treatment condition. The results showed a significant decrease in the corrosion rate (V_corr), from 4.083 mm/year for bare Mg-AZ91D to 0.001 mm/year when both the substrate and the polymer received plasma treatment. This indicates that the treatment modifies surfaces and improves interfacial bonding, enhancing polymer–metal interaction and producing durable, biocompatible coatings for medical implants. Full article

Friction stir welding (FSW) was employed to achieve a reliable joining of 2 mm thick dissimilar metals, 6061 aluminum alloy and AZ31B magnesium alloy. This study revealed the evolution of interfacial interlocking features and their impact on the mechanical properties of the joints under different welding speeds (25–35 mm/min). The results indicate that the Al/Mg FSW joint interface exhibits a strip-like interlaced structure, the morphological characteristics of which are closely related to the welding speed. For quantitative analysis, the ratio of interlocking length to plate thickness (embedding ratio) was used as a quantitative indicator of the structural interlocking feature. As the welding speed increased from 25 mm/min to 35 mm/min, the embedding ratio decreased from 13.2 to 7.9, and the average thickness of the intermetallic compound (IMC) layer decreased from 2.71 μm to 2.19 μm. Transmission Electron Microscopy (TEM) results confirmed that the Al/Mg FSW joint interface consists of a bilayer of IMCs, specifically Al₃Mg₂ and Al₁₂Mg₁₇, with thicknesses of 220 nm and 470 nm, respectively. Tensile testing of joints with different embedding ratios demonstrated that the tensile strength of the welded joint exhibits a positive correlation with the embedding ratio, reaching a maximum of 178 MPa. Full article

In this paper, an AZ31B Mg/Al clad plate with 5052 aluminum alloy as the cladding was successfully prepared by a new composite process of corrugated roll roughing + flat roll finishing. First, finite element simulation software was used to predict and analyze the rolling process. Subsequently, experimental research was carried out according to the simulation results, and clad plate samples under single corrugated rolling and corrugated–flat rolling processes were prepared. Finally, the differences between the two clad plates in shape quality, interface bonding state, and mechanical properties were systematically compared and analyzed. The results show that, compared with the traditional corrugated rolling process, the sheet formed by corrugated–flat rolling composite rolling has a flatter shape with no warpage, and its interface bonding quality is better. The specific performance is as follows: the mechanical properties were significantly improved, and the tensile strength and elongation reached 259.96 MPa and 8.11%, respectively, in the transverse direction (TD). This study provides a new strategy for the preparation of high-performance Mg/Al clad plates. Full article

The adjustable-ring-mode (ARM) scanning laser was used to perform butt welding on 0.5 mm thick TA1 titanium alloy and 304 stainless steel (SS304) thin sheets, with 1.2 mm diameter AZ61S magnesium alloy welding wire as the filling material. Microhardness test results show that the hardness distribution presented a trend of being higher in the base metals on both sides and lower in the middle filling area, with no hardening observed in the weld zone. For all specimens subjected to horizontal and axial weld bending tests, the bending angle reached 108° without any cracks occurring. When the ring power was in the range of 800–1000 W, or the scanning frequency was between 100 and 200 Hz, all the average tensile strengths of the welded joints were more than 80% of that of the AZ61S filling material (approximately 240 MPa); the maximum average tensile strength stood at 281.2 MPa, which is equivalent to 93.7% of the AZ61S. As the ring power or scanning frequency increased further, the tensile strengths of the joints showed a decreasing trend. The remelting effect of the trailing edge of the ARM laser under high energy conditions, or the scouring of the turbulent molten flow induced by the scanning beam, damages the weak links at the newly formed solid–liquid interface and increases the Fe concentration in the molten pool. This leads to a thicker FeAl interface layer during growth, thereby resulting in a decline in the mechanical properties of the welded joints. Full article

In this study, oxide coatings with layered double hydroxide (LDH) nanosheets were prepared on AZ91 magnesium alloy by a one-step low-voltage microarc oxidation (MAO) process. The microstructure and composition of the coatings were characterized using SEM, EDS, XRD, FT-IR, and XPS. The corrosion protection performance of the coatings was evaluated by electrochemical analysis and hydrogen evolution tests. The results showed that oxide coatings with Mg-Al-LDH nanosheets are successfully produced by microarc oxidation at a voltage of less than 100 V. The coating with a higher density of Mg-Al LDH nanosheets exhibited enhanced corrosion resistance. Moreover, after modification with stearic acid, the coatings displayed high hydrophobicity and corrosion resistance. Full article

Fluorination has been proposed as an effective surface modification method for magnesium. The high-temperature oxidation behavior and protective mechanism of fluorinated AZ31 magnesium alloys, especially under prolonged isothermal conditions, have not been systematically investigated. In this study, an efficient and safe surface fluorination method that requires no post-treatment was developed to directly fluorinate the surface of AZ31 machining chips using F₂ gas. By adjusting the fluorination parameters, including fluorine gas pressure, temperature, and reaction time, the content and uniformity of the surface MgF₂ layer were effectively improved. High-temperature isothermal oxidation tests demonstrated a remarkable enhancement in oxidation resistance after fluorination; specifically, the weight change of the fluorinated samples decreased from 64.65% for the untreated alloy to 0.68% after oxidation at 450 °C for 12 h. To verify the formation of the MgF₂ layer and its protective mechanism, all samples were systematically characterized before and after heat treatment using XPS, SEM/EDS, and XRD. The results confirm that direct fluorination with F₂ is an effective approach for improving the high-temperature stability of AZ31 magnesium alloy. Full article

Phosphorus recovery from wastewater as struvite via electrochemical magnesium dosing is a promising approach to address the growing demand for fertilizers. However, its large-scale implementation is often constrained by energy requirements. To overcome this limitation, this study investigates electroless struvite precipitation from cheese whey wastewater using sacrificial magnesium anodes. Under optimal conditions, up to 90% of the phosphorus was recovered within 4–6 h. In this process, spontaneous magnesium dissolution acts as the driving force for phosphorus precipitation and is strongly influenced by the wastewater’s ionic composition. To identify conditions that favor efficient recovery, the effects of ammonium, chloride, and sulfate ions were evaluated by monitoring phosphorus removal and magnesium corrosion behavior. Sulfate ions enhanced magnesium corrosion more strongly than chloride during the initial stages, likely due to stronger coulombic interactions with Mg²⁺ at the electrode–electrolyte interface, whereas chloride ions were more effective at disrupting the passivation layer that develops over time. Based on these observations, a mechanistic interpretation of ion-specific effects on anodic corrosion is proposed. Solid-phase analyses using multiple characterization techniques confirmed struvite formation, with ammonium sulfate and ammonium chloride systems yielding the highest product purity. Overall, these findings improve the understanding of electroless struvite precipitation and highlight its potential as an energy-efficient approach for nutrient recovery. Full article

Controlled-release technologies based on natural clays offer a sustainable approach to enhance the efficacy and environmental compatibility of agrochemicals. This study reports the development and evaluation of clay-based azoxystrobin (Az) formulations for controlling Magnaporthiopsis maydis, the causal agent of maize late wilt disease. Among six carriers tested, raw bentonite and sepiolite were selected for their comparable adsorption capacity (9.5% Az loading efficiency) and ease of preparation. A novel mycelial plug-immersion bioassay was established and calibrated (R² = 0.92–0.95) to assess release kinetics and antifungal efficacy, showing approximately tenfold higher sensitivity than conventional disk-diffusion or mycelial-growth inhibition assays. Sequential wash and extended incubation experiments demonstrated sustained Az release equivalent to ≥1 mg L⁻¹ over 144 h, resulting in approximately 50% (p < 0.05) fungal growth suppression. A comparative analysis of particle suspensions and supernatants revealed formulation-specific release behaviors, which differed among clay carriers. Overall, bentonite and sepiolite acted as efficient carriers that prolonged fungicide bioavailability, minimized leaching losses, and preserved biological activity. These findings provide proof of concept for clay–Az formulations as eco-friendly and cost-effective tools for late wilt management and advance understanding of clay–fungicide interactions that support sustainable, integrated disease-control strategies. Full article

Research into methods for regulating the biocorrosion rate of biodegradable magnesium implants is one of the most urgent tasks in the field of biomedical materials science. Atomic layer deposition (ALD) is a highly effective method for the preparation of nanocoatings, which can be used to regulate the biodegradation rate. The present paper presents the findings of a research study in which the most commonly used simple oxide ALD coatings (Al₂O₃, TiO₂, and ZnO) were examined, in addition to mixed coatings obtained by alternating ALD cycles of the application of ZnO-TiO₂ (ZTO) and Al₂O₃-TiO₂ (ATO). The coating thicknesses exhibited a variation within the most typical range for ALD coatings, measuring between 20 and 80 nanometres. The biocorrosion testing was conducted in Ringer’s physiological solution through the measurement of potentiodynamic polarisation curves and impedance spectroscopy. The findings demonstrated that, for Al₂O₃ coatings, the protective properties exhibited an increase with increasing thickness, while for TiO₂, the trend was found to be dependent on the type of precursor utilised. The protective properties of titanium tetraisopropoxide (TTIP) have been observed to increase with increasing thickness. Conversely, the protective properties of titanium tetrachloride (TiCl₄) have been observed to decrease. The application of mixed ZTO oxides with a thickness of 40 nm has been demonstrated to reduce the corrosion current by 1.7 and 3.4 times, depending on the use of TiCl₄ or TTIP. Furthermore, the effectiveness of ATO coatings of similar thicknesses has been shown to be higher, with a reduction in corrosion currents of 54 and 24 times for samples obtained using TiCl₄ and TTIP, respectively. A thorough analysis of the collected data unequivocally demonstrates the superior efficacy of mixed oxides in comparison to their pure oxide counterparts. Full article

This study addresses the issue of adapting the thermal drilling process for joining dissimilar thin-walled materials—sheets made of non-ferrous metal alloys and polymer composites with a thermoplastic matrix reinforced with glass and carbon fibers—without the use of connecting elements and without disrupting the continuity of the reinforcing fibers. An extensive metallographic study was conducted on bushings formed in thin metal sheets made of EN AW 6082 T6 aluminum alloy and AZ91 magnesium alloy obtained during separate drilling procedures. Experiments were also performed where the metal sheet and composite material overlapped, using both direct and sequential drilling above the melting point of the polymer matrix, applying various process parameters. The dimensions of the resulting bushings and the suitability of their profile for joining with composites were evaluated. The results suggest the possibility of joining metals and fiber composites through thermal drilling, and suitable joining process parameters and conditions are specified. To limit composite delamination, it is advisable to make a hem flange on the reverse side of the joints. CT scans confirmed the deflection of fibers around the hole in the composite without compromising their integrity. The load-bearing capacity of the joints and the possibility of creating hybrid mechanical–adhesive joints between these materials are the subject of Part Two of this study. Full article

The SNF2-related chromatin remodeler Srcap is the principal ATPase responsible for the deposition of the histone variant H2A.Z at promoters and regulatory chromatin regions. Although this activity is known to modulate transcription, its contribution to DNA replication remains unexplored. Here we show that Srcap is required for efficient replication fork progression and origin firing in mammalian cells. Using RNA interference in human PC3 cells, we found that Srcap depletion leads to a ~25% reduction in fork elongation rate, decreased replication fork density, accumulation of the replication-stress marker γH2AX, and reduced chromatin-bound H2A.Z. High-resolution expansion microscopy further revealed diminished intensity and increased spacing of replication foci, consistent with reduced origin activation. Transcriptomic analysis of published data identified broad downregulation of replication-associated genes. These data uncover a dual mechanism by which Srcap sustains replication efficiency—through both H2A.Z-dependent chromatin organization and transcriptional maintenance of the replication machinery. Our findings establish Srcap as an important coordinator of replication dynamics, with implications for genome stability. Full article