Zn In Solution Research Articles

Microstructures and mechanical properties of a novel Al-5Mg-3Zn alloy with the combined additions Sc and Zr

The study investigated the impact of Sc and co-addition of Sc and Zr on the dispersoids, subsequent grain structures and aging precipitations, and the ultimate mechanical properties of Al-5Mg-3Zn-xSc-yZr (x + y = 0.2wt.%) alloys were studied. The results indicate that the co-addition of Sc and Zr produces the highest number density of dispersoids among the three alloys. The Al-5Mg-3Zn alloy mainly comprises fully recrystallized equiaxial grains (close to 100%) after solution treatment. In contrast, the recrystallization ratio of Al-5Mg-3Zn-0.1Sc-0.1Zr remarkably decreases to 9% owing to the presence of fine and dense Al3M dispersoids to impede the mobility of sub-grain boundaries. Adding the Sc element alone reduces the number density of the T-Mg32(Al, Zn)49 and enhances their size during the subsequent aging treatment, while the co-addition of Sc and Zr elements shows an opposite trend. The primary factor contributing to this result is that the microalloying of Sc and co-addition of Sc and Zr affects the diffusion of Mg and Zn solute atoms in Al-5Mg-3Zn alloys. Consequently, the peak-aged Al-5Mg-3Zn-0.1Sc-0.1Zr alloys exhibit a yield strength of 481MPa, an ultimate tensile strength of 547MPa, and an elongation of 12%, which is superior to the reported Al-5Mg-3Zn alloys. The good strength-ductility synergy can be attributed to the combination of a high number density of dispersions, grain refinement, and high-volume fraction nanoprecipitates.

Study on the interfacial microstructure and fracture mechanism of Al/Mg composites with Zn interlayer by cyclic hot pressing

Using the cyclic hot pressing method, Al/Mg laminated composites with a Zn interlayer were prepared, and the effect of temperature on the composite interfaces was studied. At 420℃, the composites interface is composed of HCP-Zn solid solution near the Al side and Laves phase near the Mg side. At 460℃, FCC-Al phase and τ-phase appear near the Al side, while τ-phase and HCP-Mg solid solution appear near the Mg side. Above 500℃, the interface is mainly composed of Al-Mg intermetallic compounds. The change of solubility during the formation of the composite causes the polarization of solute atoms in Zn and Al solid solutions, resulting in defects, such as increased grain boundary stress and lattice distortion. These defects lead to failure of the interface near the aluminum side of the composites. Composites prepared at 420℃ show the best ductile fracture properties. With the increase of preparation temperature, the fracture mode is transformed into brittle fracture induced by β-phase.

ANTIMICROBIAL, ANTIOXIDANT AND CYTOTOXICITY STUDY OF Cu(II), Zn(II), Ni(II), AND Zr(IV) COMPLEXES CONTAINING O, N DONOR SCHIFF BASE LIGAND

Objective: The aim of the research is to synthesize and characterize Cu(II), Zn(II), Ni(II), and Zr(IV) complexes with a Schiff base ligand, and evaluate their antibacterial and antioxidant properties. Methods: The ligand was synthesized by refluxing salicylaldehyde with o-phenylenediamine in ethanol, forming a yellow-orange product. The complexation reaction involved stirring ethanolic solutions of Zn(II), Cu(II), Ni(II), or Zr(IV) salts with a Schiff base ligand. Thermal decomposition of Zn(II), Cu(II), Ni(II), and Zr(IV) complexes was analyzed under nitrogen, heating at 30 °C/min, measuring weight loss from ambient temperature to 800 °C. The antibacterial activity, antioxidant properties, and cytotoxicity of the synthesized compounds wereexamined using reported methods. Results: Cu(II), Zn(II), Ni(II), and Zr(IV) complexes with a Schiff base ligand were synthesized. Analyzed through Fourier-transform infrared spectroscopy (FTIR), Ultraviolet-visible (UV-vis) and physiochemical tests and confirmed the structures. Magnetic susceptibility and electronic spectra suggested geometries, supported by thermogravimetric data. Antibacterial tests revealed complexes had higher activity than ligands, and also showed antioxidant properties. Conclusion: Cu(II), Zn(II), Ni(II), and Zr(IV) Schiff base complexes were synthesized, showing tetrahedral or square planar geometries. They exhibited thermal stability and strong antibacterial activity, outperforming the ligand alone.

Evaluation of Fe-doped calcium phosphate for 65Zn sorption

65Zn, a fission product found in cooling water reactors, poses significant environmental risks due to its toxicity. This study explores the use of Ca–Fe2+ phosphate (SB1) and Ca–Fe3+ phosphate (SB2) as sorbents for Zn(II), prepared via the wet chemical method. The Zn(II) solution, spiked with 65Zn radionuclides, was analyzed radiometrically. Optimal sorption conditions were determined to be pH 4.5, a contact time of 24 h, and a sorbate volume to sorbent mass ratio of 1:10 at 20 °C. The Langmuir isotherm model best fit the adsorption data, indicating monolayer adsorption capacities of 0.574 mmol g−1 for SB1 and 0.621 mmol g−1 for SB2. Sorption kinetics followed a quasi-nth-order model. Furthermore, 0.1 M FeCl3 effectively desorbed 99% of Zn(II) from both sorbents. The sorption process was found to be spontaneous and endothermic. These findings suggest that SB1 and SB2 have potential applications in recycling Zn(II) from the black mass of expired batteries.

Strengthening of edge prism dislocations in Mg–Zn by cross-core diffusion

The activation of prismatic slip in Mg and its alloys can be beneficial for deformation and forming. Experiments show that addition of Zn and Al solutes have a softening effect at/below room temperature, attributed to solutes facilitating basal-prism-basal cross-slip of prismatic screw dislocations, but a strengthening effect with increasing temperature. Here, the dynamic strain aging mechanism of cross-core diffusion within the prismatic edge dislocation is investigated as a possible mechanism for the strengthening at higher temperatures. First-principles calculations provide the required information on solute/dislocation interaction energies and vacancy-mediated solute migration barriers for Zn solutes around the dislocation core. Results for Mg–0.0045Zn show that cross-core diffusion notably increases the stress for prismatic edge dislocation glide but that the strengthening remains roughly 30% of the experimental strength. Other possible strengthening mechanisms of (i) solute drag of the prism edge dislocation and (ii) solute interactions and/or diffusion within the prismatic screw core, are then briefly discussed with some quantitative assessments pointing toward areas for future study.

Achieving enhanced thermal conductivity and mechanical properties in Mg-Zn-Gd-Zr alloys via regulation microstructure characteristics

It is well known that the microstructure of metallic materials determines the mechanical properties. However, the effect of microstructure on thermal conductivity lacks an accurate quantitative description of this relationship. In this work, the mechanism of variation in mechanical and thermal conductivities with microstructure was revealed by the characterization of cast, heat-treated, and extruded Mg-xZn-yGd-0.6Zr (wt%) alloys: ZV66, ZV62, and ZV26. The contributions of solution atoms, second phases, grain size, and dislocations to the yield strength and thermal conductivity were quantitatively calculated, and their effects on the plasticity and work-hardening behavior were qualitatively analyzed. The results show that hot extrusion promotes the precipitation of nanoprecipitates, such as MgZn2, Mg4Zn7, and Mg5Gd, resulting in the reduction of Zn and Gd solute atoms and the introduction of high-density dislocations and grain boundaries. The extruded ZV66 alloy exhibits excellent mechanical properties and thermal conductivity (a tensile yield strength of 232 MPa, an elongation of 22 %, and a thermal conductivity of 127.6 W/(m·k)); these values are better than those reported for similar products. The achievement of high strength and thermal conductivity is attributed to the precipitation of solute atoms to improve thermal conductivity in addition to grain boundary strengthening and work-hardening strengthening to improve strength. These findings provide new insights into achieving excellent strength–thermal conductivity property amalgamations in magnesium alloys by tailoring their microstructure.

Impact of different irrigation & trace metals treatments on onion (Allium cepa L.) plant growth cultivated in rural and urban soils

AbstractThe present research attempts to evaluate the response of Allium cepa L. to different irrigation treatments and to indicate the optimum scheme along with plant growth, throughout a pot experiment during Spring 2021. The experimental procedure consisted of two different soil types, three treatments of irrigation and two levels of Cu and Zn (low and high), in four replications each. Irrigation events started when the lower allowable limit (LAL) reached a defined percentage of filed capacity (FC): 40% FC, 60% FC, and 75% FC and an irrigation event occurred with irrigation doses (Dn) equal to 60% FC, 40% FC, and 25% FC, respectively, to reach the value of FC. According to the results, the minimum yield was achieved by both soil types when Cu and Zn solution concentration and water stress were at their highest levels, although light texture soil (loamy sand—LS) allowed for superior growth. The optimum scheme was: the lower concentration of Cu and Zn solution along with LAL equal to 60% FC at the loamy sand soil. The outcomes suggest that frequent short irrigation doses at light-texture soils can result in yield response indicators when planted in pots. Furthermore, the influence of Cu and Zn cations at low concentrations can be advantageous for onions because Cu cations provide protection against fungal diseases, while Zn cations serve as nutrient support reducing the risk of metals deficiency.

Determination of the maximum bioaccumulation capacity of various metals in leaves of two Tillandsia species.

Tillandsia species are plants from the Bromeliaceae family which display biomonitoring capacities in both active and passive modes. The bioaccumulation potential of Tillandsia aeranthos (Loisiel.) Desf. and Tillandsia bergeri Mez acclimated to Southern/Mediterranean Europe has never been studied. More generally, few studies have detailed the maximum accumulation potential of Tillandsia leaves through controlled experiments. The aim of this study is to evaluate the maximum accumulation values of seven metals (Co, Cu, Mn, Ni, Pb, Pt, and Zn) in T. aeranthos and T. bergeri leaves. Plants were immersed in different mono elemental metallic solutions of Co (II), Cu (II), Mn (II), Ni (II), Pb (II), Pt (IV), and Zn (II) ions at different concentrations. In addition, cocktail solutions of these seven metals at different concentrations were prepared to study the main differences and the potential selectivity between metals. After exposure, the content of these metals in the leaves were measured by inductively coupled plasma-optical emission spectrometry. Data sets were evaluated by a fitted regression hyperbola model and principal component analysis, maximum metal loading capacity, and thermodynamic affinity constant were determined. The results showed important differences between the two species, with T. bergeri demonstrating higher capacity and affinity for metals than T. aeranthos. Furthermore, between the seven metals, Pb and Ni showed higher enrichment factors (EF). T. bergeri might be a better bioaccumulator than T. aeranthos with marked selectivity for Pb and Ni, metals of concern in air quality biomonitoring.

Laser Synthesis of Catalytically Active Materials for Organic Synthesis and Sensor Technology

Introduction: The catalytic activity of metallic nanomaterials depends on their surface morphology. A widely known method is the laser synthesis of metal nanostructures by depositing on dielectric surfaces from aqueous solutions containing metal complexes. The article analyzes the factors that favor the production of conductive, catalytic, and sensory-active deposits by laser method. It is shown that the two main factors is the presence of a large number of charged defects on heterophase surfaces and the structure of metal-containing complexes in solution. This is typical for mono- and bimetallic alloys, the components of which interact with the laser beams according to the autocatalytic type. Using the example of laser deposition from solutions of Co, Ni, Fe, Zn, and Ag salts with homo- and heterophase dielectrics, the sensory and catalytic properties of the deposits are compared by impedance spectroscopy and voltammetry. It has been shown that heterophase precipitation significantly enhances the catalysis response. Background: It is known that the highest catalytic activity exhibits nanostructured and highly porous materials with a large specific surface area and materials containing surface heterogeneity in the form of charged acid-base centers. Such materials are necessary for the creation of new catalysts for organic synthesis and for the creation of new sensor materials for enzyme-free microbiosensors. Active development of new methods for the synthesis of such materials is underway. But not all of them give the expected result. Methods: Laser synthesis methods have the best prospects, including the method of laser-induced metal deposition. This is the laser synthesis of metal nanostructures by depositing dielectric surfaces from aqueous solutions containing metal complexes. Results: Аrticle analyzes the factors that favor the production of conductive, catalytic, and sensory-active deposits by laser method. It is shown that the two main factors are the presence of a large number of charged defects on heterophase surfaces and the structure of a metal-contained complex in solution. This is typical for mono- and bimetallic alloys, the components of which interact with the laser beam according to the autocatalytic type. Using the example of laser deposition from solutions of Co, Ni, Fe, Zn, and Ag salts with homo- and heterophase dielectrics, the sensory and catalytic properties of the deposits are compared by impedance spectroscopy and voltammetry. Conclusion: It has been shown that heterophase precipitation significantly enhances the catalysis response. It is shown that the laser deposition reaction has an autocatalytic mechanism in a dynamic mode. The results of autocatalysis can be used in a stationary mode to create a microbiosensor for glucose, as well as to create a technology for laser refining rare metals and hydrogen energy in a dynamic mode.

A triphenylamine derivative with multistimuli responsive behavior and high-contrast vapochromism of its Zn(II) complex

In this work, we designed and synthesized a novel multifunctional molecule, (E)-2-(4-(diphenylamino)styryl)-5-(4-pyridyl)-8-quinolinol (HL), which possessed D-π-A structure and exhibited optical responses to acid-base vapor and Zn(II) ions. Zn(II) complex of HL (W1) was obtained and characterized by SC-XRD. Spectral experiments demonstrated that complex W1 displayed aggregation-induced emission enhancement (AIEE) property, which was exact opposite to the aggregation-caused quenching effect of HL. The quantum yield of W1 (15%) was much higher than that of HL (2.1%) in the solid state. Both HL and complex W1 involved sp2 hybrid N atoms, whose protonation and deprotonation gave rise to reversible acidochromism with high contrast. The mechanism was clarified by XPS, 1H NMR, infrared spectroscopy, elemental analysis, PXRD and thermogravimetry results. Benefiting from excited state intramolecular proton transfer in HL together with AIEE of W1, HL could recognize Zn(II) sensitively in aqueous media. The detection limit of HL for Zn(II) reached as low as 5.02 × 10−8 M. An anti-counterfeiting application was realized using HL-loaded test strip, which exhibited fluorescence response, but no color change upon exposure to Zn(II) solution. In addition, HL and W1 solids were combined to develop a stimuli induced encryption/decryption strategy successfully based on their reversible acidochromic behaviors.

Enhanced grain boundary cohesion mediated by solute segregation in a dilute Mg alloy with improved crack tolerance and strength

Effects of solute segregation at grain boundaries (GBs) on the deformation mechanism and fracture behavior remain obscure for magnesium (Mg) alloys. Here, by introducing Zn segregation at GBs, we obtained an Mg-0.5Al-0.4Mn-0.2Ce-0.4Zn (wt.%) alloy achieving fracture elongation (FEL) of ∼33.6 %, with a remarkable FEL improvement by 100 % in comparison to Zn-free counterpart. Meanwhile, the tensile yield strength (TYS, 195.5 MPa) is increased by ∼27.5 MPa after trace Zn addition. Although trace Zn addition improves the fraction of GBs with high misorientation, it reconciles crack tolerance with enhanced strength. The introduction of Zn not only promotes pyramidal 〈c + a〉 slips and inhibits twinning nucleation, but also enhances the GB cohesion by Zn segregation. Based on in-situ microstructure observation, we found that the enhanced GB cohesion enables the segregation-inspired hierarchical crack buffering, as well as deflecting and branching. Enhanced GBs can also facilitate the continuous emission of 〈c + a〉 dislocations in neighboring grains irrespective of the onset of microcracks, forming a plastic zone to retard local strain concentration, thus avoiding microcrack percolation and attaining a crack-mediated elongation reserve of above 15 %. Besides, the higher TYS in the Zn-containing alloy mainly stems from the enhanced solid-solution strengthening of Zn solutes, thus achieving strength and crack tolerance synergy.

Unlocking the potential of a zirconium-based MOF for advanced protective coatings: Delve into the UIO-66 smart release functioning for a bio-based Zn2+ complex

In recent years, the incorporation of nanoreservoirs into epoxy coating (EP) formulations has gained significant traction, primarily for their role in delivering self-healing capabilities. This research endeavor is centered around the synthesis and application of a zirconium-based metal-organic framework (MOF) known as UIO-66, specifically designed for the encapsulation of corrosion inhibitors. A novel breakthrough is achieved by simultaneously loading of a green organic inhibitor (Spand extract) and inorganic zinc cations into the highly porous UIO-66, yielding a pioneering bio-based controlled-release nanoreservoir, denoted as UIO-SP.Zn. The UIO-SP.Zn nanoreservoir is characterized through multiple techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller surface area analysis, thermogravimetric analysis, and field emission scanning electron microscopy. The controlled-release and pH-sensitive behavior of the UIO-SP.Zn structure are thoroughly evaluated through inductively coupled plasma and UV–vis spectroscopic analyses at three separate pH levels. Electrochemical impedance spectroscopy results underscore the remarkable enhancement in corrosion protection for steel components exposed to a saline medium (3.5 % NaCl) upon the addition of a 1000 ppm UIO-SP.Zn solution, achieving a total resistance of 10,350 Ω.cm2 after a 96 h immersion. The self-healing and active protection of scratched nano-coatings are meticulously examined through electrochemical techniques, revealing that the EP-coated panel incorporating UIO-SP.Zn nanoreservoirs (EP/UIO-SP.Zn) exhibits a substantial impedance (exceeding 60 kohm.cm2) even after prolonged exposure (72 h). Furthermore, the coating's dry pull-off strength registers a notable increase (40.3 %), while delamination is reduced by 50.1 % compared to the unmodified EP coating, signifying the promising adhesion properties of EP/UIO-SP.Zn.

Modulating the Electrolyte Inner Solvation Structure via Low Polarity Co‐solvent for Low‐Temperature Aqueous Zinc‐Ion Batteries

Aqueous zinc‐ion batteries are regarded as the promising candidates for large‐scale energy storage systems owing to low cost and high safety; however, their applications are restricted by their poor low‐temperature performance. Herein, a low‐temperature electrolyte for low‐temperature aqueous zinc‐ion batteries is designed by introducing low‐polarity diglyme into an aqueous solution of Zn(ClO4)2. The diglyme disrupts the hydrogen‐bonding network of water and lowers the freezing point of the electrolyte to −105 °C. The designed electrolyte achieves ionic conductivity up to 16.18 mS cm−1 at −45 °C. The diglyme and ClO4− reconfigure the solvated structure of Zn2+, which is more favorable for the desolvation of Zn2+ at low temperatures. In addition, the diglyme effectively suppresses the dendrites, hydrogen evolution reaction, and by‐products of the zinc anode, improving the cycle stability of the battery. At −20 °C, a Zn||Zn symmetrical cell is cycled for 5200 h at 1 mA cm−2 and 1 mA h cm−2, and a Zn||polyaniline battery achieves an ultra‐long cycle life of 10 000 times. This study sheds light on the future design of electrolytes with high ionic conductivity and easy desolvation at low temperatures for rechargeable batteries.

A trinuclear Zn (II) schiff base dicyanamide complex attenuates bacterial biofilm formation by ROS generation and membrane damage and exhibits anticancer activity

A trinuclear Zn (II) complex, [(ZnL{N(CN)2})2Zn], termed complex 1 has been synthesized by the reaction of an aqueous solution of sodium dicyanamide to the methanolic solution of Zn (CH3COO)2, 2H2O and corresponding Schiff base (H2L) which is derived from 1:2 condensation of 1, 4 butane diamine with 3-ethoxy salicylaldehyde. Complex 1 is characterized by elemental analysis, IR, UV and Single X-ray diffraction study. Drug resistance is a growing global public health concern that has prompted researchers to look into advanced alternative treatment modalities. In this context, complex 1 has shown promising antibacterial and antibiofilm efficacy against gram-positive Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus strains. Complex 1 attenuated Staphylococcal biofilm formation by reducing several virulence factors including the formation of extracellular polysaccharide matrix, slime, haemolysin, staphyloxanthin, auto-aggregation, cell surface hydrophobicity, and motility. Notably, complex 1 mechanistically potentiated Reactive Oxygen Species (ROS) generation within the bacterial cells, leading to the damage of bacterial cell membrane followed by DNA leakage and thereby impeding the growth of Staphylococcus aureus. Furthermore, complex 1 significantly exhibited anticancer activity by reducing the growth of prostate adenocarcinoma cells. It obstructed the migration of cancer cells by potentiating apoptosis and arresting the cell cycle at the G2/M phase. In summary, complex 1 could act as a potent candidate for the generation of novel antibacterial, antibiofilm as well as anticancer treatment regimens for the management of drug-resistant biofilm-mediated Staphylococcus aureus infection and lethal prostate malignancy.

Effect of Zn Applied with or Without Palm Stearin Coated Urea on The Growth and Mineral Element Concentration of Maize (Zea mays L.)

Inhibition of ammonia (NH3) volatilization by deaccelerating urea hydrolysis rate in Central Anatolian lands is the indispensable approach for eco-friendly fertilization and nitrogen use efficiency (NUE). Nitrogen (N) and zinc (Zn) are critically limited here in alkaline soils. An experiment was conducted under controlled conditions to determine the availability of Zn applied as a solution and bound with polymer palm stearin (PS) coating material as a urease inhibitor. The treatments consisted of urea as a commercial commodity, urea with PS only, urea impregnated with PS and Zn, Zn-coated urea, and Zn in solution (SOL) form. During winter, 2019-20, the experiment was conducted in the glasshouse of the department of Soil Science and Plant Nutrition at Ankara University, Türkiye. Data indicated that Zn with PS and in SOL form produced more growth traits i.e., plant height (130 cm), stem girth (13.2 mm), shoot dry matter (4.63 g plant-1), root dry matter yield (0.61 g plant-1), and chlorophyll (42.16 mg g-1) content (p<0.01). Similarly, we had higher concentration of N (3.19%) and Zn (50.46 mg kg-1) content in maize plants (p<0.01) as compared to control. In conclusion, Zn at the rate of 10 mg kg-1 either in solution or coated with urea seems highly effective to sustain better crop productivity and NUE. While concerning N and Zn content, coated urea with Zn markedly responded as compared to Zn in SOL. Synergism between N and Zn can lead to better fertilizer management

Green and sustainable practices for an energy plant cultivation on naturally contaminated versus spiked soils. The impact of ageing soil pollution in the circular economy framework

Silybum marianum L. Gaertn. or milk thistle is an energy-produced weed that has been shown to be tolerant of heavy metal-contaminated soils. In the present study, its cultivation was studied in soils laboratory-spiked (artificial) with Cu and Zn solutions. Meanwhile, plant growing on naturally contaminated soils of Mediterranean regions, both urban and rural, was investigated. The metal concentrations spiked in artificial polluted soils were estimated to be roughly equivalent to those in naturally contaminated soils. Plants grown in artificially contaminated soils incorporated the metal added to the soils more rapidly and in higher proportions. The contamination of soil samples was carried out using different chemical reagents, salts containing the metals with oxidation number II, highlighting the fact that the reagent containing the metal is crucial regarding artificial soil pollution. Statistically significant differences were observed between the individual pollution patterns, as far as plant metals uptake concern. It was also found that the aged, contaminated soils transfer lower levels of metals to the plants. Therefore, aging or weathering of contamination alters toxicity levels in the soil environment by determining transport and uptake into the soil-to-plant system. Eventually, from the present research, it emerged the fact that in urban soils that have aged perennial pollution, the uptake of metals by plants is probably lower than in rural ones. Furthermore, with proper management, it is possible to grow plants, with low nutrient requirements, in urban soils by adopting smart, green and eco-friendly techniques, enhancing sustainable cultivation in the framework of circular economy.

Growth mechanism under the supply-limited regime in mist chemical vapor deposition: presumption of mist droplet state in high-temperature field

In mist CVD, investigation of the dependence of the growth rate on the solution concentration and precursor supply amount in the growth of ZnO films using a methanol-based solution of Zn(acac)2 revealed that the reaction is a rate-determination process of the supply-limited regime. Based on this result, the diffusion coefficient of gasified Zn(acac)2 at standard ambient temperature and pressure (SATP) was calculated to be approximately 10−6m2/s, where the diffusion rate was derived from the relation between the precursor supply amount and the film formation amount, assuming that all precursors were gasified in the reactor. The derived values were approximately one order of magnitude lower than the typical diffusion coefficient of 10−5m2/s in the gas phase at SATP. Several factors considered were unable to explain the much lower diffusion coefficient. Therefore, this result contradicts the assumption that all precursors are gasified in the reactor, and it is presumed that droplets might remain in the liquid–gas phase.

STRUCTURE, OPTICAL PROPERTIES AND PHOTOCATALYTIC ACTIVIYY OF UNDOPED, La2O3-DOPED ZnO NANOCOMPOSITES

La-doped ZnO nanocomposites with di­ffe­rent content of La2O3 (1–5%) were obtained by the Pechini method from their nitrate solutions. The solutions of Zn2+ and La3+ nitrates were preliminary obtained by dissolving of zinc and lanthanum oxides with a content of the main component of 99.99% in nitric acid. The influence of lanthanum doping the on the microstructure, morphology, optical pro­perties and photocatalytic activity of the ZnO nanopowders were examined. The properties of the nanopowders were studied by using X-ray phase analysis, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy. The samples were subjected to X-ray powder diffraction using a DRON-3 diffractometer (Cu-K radiation) at room temperature. The scan angle was 0.05–0.1 ° in the range 2 = 15–90 °. X-ray phase ana­lysis confirms the formation of single phase of La2O3-doped ZnO powders on diffractograms. Raman light scattering and photoluminescence spectra were recorded using a Horiba Jobin‑Yvon T64000 spectrometer equipped with a CCD detector at room temperature in the inverse scattering geometry. According to SEM results, the powders characterized a conglomerate structure. The undoped ZnO has an average particle size of 43 nm, while the average particle size of La3+-doped ZnO ranges from 64 to 80 nm. It was established that the morphology of powder particles primarily depends on the content of La3+ in the material. An increase in the amount of La3+ in zinc oxide leads to an increase in the specific surface area (from 3.8 to 11.8 m2/g). In the photoluminescence spectra of ZnO powders, with increasing La2O3 concentration, bands at 400 nm are observed due to the appearance of impurities that cause of interstitial zinc and zinc vacancy defects and their broade­ning with a shift to the long-wave region. Photocatalytic properties of ZnO pow­ders doped with lanthanum oxide were in­vestigated using Methyl Orange as a model dye under Osram Ultra-Vitalux lamp (300 W) irradiation. A present result indicates that the obtained powders are potential candidate for the practical application in photocatalysis.

Exploring the influence of cosegregation on mechanical properties of Mg [formula omitted] twin boundaries: A first-principles investigation

This study employs first-principles calculations to investigate the impact of solute segregation on the mechanical properties of the Mg twin boundary (TB). The investigation delves into single-element segregation and multielement cosegregation at the Mg{101¯1} twin boundary. Several parameters, including segregation energy, solubility energy, and strengthening/embrittlement energy, are determined, and Voronoi volume and electronic structure evolution are analyzed. The study discloses the effects of 21 solute single-segregation, as well as the segregation mechanism of Ca, Y, and Zn solute elements in paired combinations. A comparative assessment of the optimal combination for cosegregation of Ca/Y atoms with larger atomic radii and Zn atoms with smaller atomic radii reveals that the solute elements Ca and Y induce more robust energy changes at the interface segregation than Zn. Additionally, electronic structure analysis suggests that charge transfer between solute atoms with large atomic radii and solute atoms with small atomic radii can strengthen the chemical bond at the twin boundary, thereby enhancing the maximum tensile degree, ductility, and formability of the material. The outcomes of this investigation have significant theoretical implications for composition design and the development of novel high-performance multielement magnesium alloys.

Role of Zn addition on the microstructure and tensile property in Mg–Mn–Nd alloys

The role of Zn addition (1, 2 wt%) on the microstructural characteristics and tensile properties of the extruded Mg–1Mn–1Nd (MN11) alloy is discussed. The addition of Zn negligibly influences the particle type; however, Zn addition causes un–homogeneous distribution structure firstly and then develops homogeneous structure because of the change of size and distribution of Mg12Nd particles. The MZN111 sheet shows higher yield strength (YS) along the extrusion direction (ED), and lower YS along the transverse direction (TD), compared to the MN11 sheet. This improvement is attributed to the Zn solute atoms via solid-solution strengthening effect, while the reduction is ascribed to the formation of TD–orientation texture and coalescence of dynamic recrystallized (DRXed) grains. As the Zn content increases to 2 wt%, The MZN121 sheet with highest strength can be ascribed to the homogeneous distribution of finest grains via the grain–boundary strengthening effect and more Zn solute atoms via solid–solution strengthening effect. The increased size of Mg12Nd particles with 1 wt% Zn content and coalescence of DRXed grains, which can significantly reduce the ductility of MZN111 sheet. Further, the ductility enhancement of the MZN121 sheet is mainly due to the homogeneous distribution of fine grains and homogeneous alignment of Mg12Nd particles.