Mixture Of Zn Research Articles

An efficient synthetic approach towards a single diastereomer of (2R,3R)-N2,N3-bis((S)-1-phenylethyl)butane-2,3-diamine via metalation and demetalation

A facile synthetic approach has been adopted towards the synthesis of (2R,3R)-N2,N3-bis((S)-1-phenylethyl)butane-2,3-diamine via demetalation of its dichloro Zn(II) complex, which itself was separated from a mixture of diastereomeric Zn(II) complexes by fractional crystallization. The synthesized chiral 1,2-diamine ligand was evaluated as a chiral auxiliary for the Cu(II)-catalysed asymmetric Henry reaction of 3-phenylpropanal and nitromethane, yielding (S)-1-nitro-4-phenylbutan-2-ol in excellent yields (up to 99%) and enantioselectivities (up to 97%). A facile synthetic approach towards (2R,3R)-N2,N3-bis((S)-1-phenylethyl)butane-2,3-diamine (2b) via fractional crystallization and demetalation of its Zn(II) complex has been adopted. 2b served as a highly enantioselective pro-ligand with Cu(OAc)2 for asymmetric Henry reaction of 3-phenylpropanal and nitromethane in the presence of base with 97% > ee and 99% yield.

A detailed computational exploration and experimental surface/electrochemical analyses of mild steel functionalized by zinc-aminotris methylene phosphonic acid complex film

In the present integrated experimental/theoretical work, the synergistic inhibition effects of aminotris methylene phosphonic acid (ATMP) and Zn ions for steel corrosion mitigation in NaCl solution were examined. The inhibition property of ATMP:Zn mixture was evaluated by electrochemical approaches including potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). In addition, the chelation between ATMP‑zinc ions and/or iron cations was investigated applying various morphological approaches. The ATMP and ATMP-Zn complex chemical structures were identified via UV–Vis and FT-IR spectra. According to EIS outcomes, the excellent inhibition efficiency of about 99% was achieved within 72 h steel subjection to 3.5% NaCl media containing 200:600 ppm ATMP:Zn mixture. The PDP plots disclosed that the complex inhibitors mainly retarded the steel corrosion cathodically. Furthermore, FE-SEM and AFM microstructures analyses clarified the emergence of a high-coverage ATMP:Zn complex inhibitive layer over metallic adsorbent, evidencing significant corrosion mitigation. The detailed results elucidated from EDS and XPS spectra ensured the successive chemical bonding of ATMP molecules with zinc and/or iron ions. Alongside experiments, fundamental theoretical studies at detailed microscopic levels (i.e., atomic and electronic) were conducted using molecular simulations and quantum mechanics (QM). Monte Carlo (MC) combined with molecular dynamics (MD) was applied for assessing the organic-inorganic inhibitor adsorption features. Additionally, electronic-structure QM calculation on the basis of density functional theory (DFT) was adopted so as to fundamentally analyze the reactive sites determining the inhibitor adsorption. The outcomes elucidated by MC/MD tools ensured the surface adsorption propensity of hybrid inhibitors. The DFT based observations proposed that the inhibitors adsorption likely occurs at interface through donor-acceptor interactions.

Rapidness- and Sensitivity-Based Comparison of Behavioral and Respiratory Responses of European Perch and Rainbow Trout to Metal Mixture Exposure

The aim of the study was to investigate acute (96-h LC50) toxicity of the complex metal (Zn, Pb, Cd, Cu, Ni and Cr) mixture (MIX) to European perch (Perca fluviatilis) and rainbow trout (Oncorhynchus mykiss), and to examine differences between locomotor and respiratory endpoints based on rapidness and sensitivity of fish responses to short-term (2h) metal mixture exposure. MIX was prepared taking into consideration the maximum-permissible-concentrations (MPC) set for these metals in EU inland waters (Directive 2008/105/EC). The studied behavioral and respiratory responses of O. mykiss, in contrast to those of P. fluviatilis, were found to be significantly affected by the relationship between exposure duration and treatment. In O. mykiss, gill ventilation frequency (GVF) was found to be the most rapid and sensitive endpoint of all the investigated ones. However, the investigated behavioral and respiratory endpoints of P. fluviatilis showed its behavioral insensitivity to MIX exposure.

Influence of foliar micronutrients on growth, yield and quality of Khasi mandarin (Citrus reticulata Blanco) in Mizoram

An experiment was conducted during 2016 and 2017 at Mizoram University, Aizawl, Mizoram to study the influence of foliar micronutrients on growth, yield and quality of Khasi mandarin. The design adopted was randomized block design with 16 treatments such as T1: Foliar application of zinc (Zn), T2: Foliar application of manganese (Mn), T3: Foliar application of copper (Cu), T4: Foliar application of boron (B), T5: Foliar application of Zn+Mn, T6: Foliar application of Zn+Cu, T7: Foliar application of Zn+B, T8: Foliar application of Mn+Cu, T9: Foliar application of Mn+ B, T10: Foliar application of Cu +B, T11: Foliar application of Zn+Mn+Cu, T12: Foliar application of Zn+Mn+B, T13: Foliar application of Zn+Cu+B, T14: Foliar application of Mn+Cu+B, T15: Foliar application of Zn+Mn+Cu+B and T16: Control (no micronutrients). From the pooled data of two consecutive years during the experiment, foliar application of Zn+Cu+B (T13) showed maximum plant height, stem girth, maximum plant canopy spread, highest fruit set %, yield, highest number of fruits per plant, fruit physical and biochemical parameters like largest fruit length, fruit diameter, fruit weight, minimum fruit acidity and highest TSS/Acid ratio, while highest TSS was observed with treatment which received micronutrient mixture of Zn+Mn+Cu+B (T15) against control which recorded the least in all the parameters.

Stream Mesocosm Experiments Show Significant Differences in Sensitivity of Larval and Emerging Adults to Metals.

Evaluations of aquatic insect responses to contaminants typically use larval life stages to characterize taxa sensitivity, but the effects of contaminants to emerging terrestrial adults have received less attention. We present the results of two stream mesocosm experiments that exposed aquatic insects to mixtures of Cu and Zn. We compared responses of larvae and emerging adults in a single-species experiment with the mayfly Rhithrogena robusta and a benthic community experiment. Results showed that R. robusta larvae and emerging adults were highly tolerant of metals. In the benthic community experiment, larval and emerging adult life stages of the mayfly Baetidae were highly sensitive to metals exposure, with significant alterations in adult sex ratios. In contrast, the emergence of Chironomidae (midge) was unaffected, but larval abundance strongly decreased. Timing of adult emergence was significantly different among treatments and varied among taxa, with emergence stimulation in Chironomidae and delays in emergence in R. robusta and Simuliidae (black fly). Our results demonstrate that metal tolerance in aquatic insects is life stage dependent and that taxa sensitivity is influenced by a combination of physiology and phylogeny. Regulatory frameworks would benefit by including test results that account for effects of contaminants on metamorphosis and adult insect emergence for the development of aquatic life standards.

Alleviative effects of dietary Indian lotus leaves on heavy metals-induced hepato-renal toxicity, oxidative stress, and histopathological alterations in Nile tilapia, Oreochromis niloticus (L.)

Heavy metals (HM) are widespread contaminants of water affecting aquatic organisms and aquatic ecosystems. Indian lotus, Nelumbo nucifera (Gaertn.), is a beneficial medicinal plant that exhibits several pharmacological properties. It is hypothesized that incorporation of Indian lotus leaf (ILL) powder may be able to alleviate toxic effects exerted by a mixture of lead (Pb), cadmium (Cd), mercury (Hg), and zinc (Zn) in Nile tilapia, Oreochromis niloticus (L.). A total of two hundred and forty fish were randomly allocated into eight groups in triplicate, in a bifactorial design (4 ILL levels × 2 HM exposures). The fish in the first four groups were fed on a basal diet (39.9% crude protein) that was enriched with 0.0, 0.1, 0.2, and 0.4% ILL (in G1–G4, respectively), with no HM exposure. In the remaining four groups, fish were fed with the same diets and, in addition, were exposed to 1/20 of the 96 h-LC50 of Pb, Cd, Hg, and Zn mixture (in G5–G8, respectively), for 45 days. The HM exposure significantly elevated the levels of serum alanine and aspartate aminotransferases, creatinine, urea, malondialdehyde, and activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX). The expression level of hepatic metallothionein (MT) was up-regulated as well as high residual levels of HM in fish musculature were recorded in the HM-exposed fish. Two-way ANOVA revealed that all the studied variables were significantly affected by the ILL supplementation, HM exposure, and their interaction. Moreover, levels of MDA, CAT, SOD, and MT showed significant positive correlations with HM concentrations. Moreover, necrosis and degeneration of hepatopancreatic cells with congestion, hyperplasia, and fusion of gills lamellae were observed in HM-exposed fish. Interestingly, ILL supplementation, especially in the fish fed with 0.2 and 0.4% ILL, was observed to reduce the HM concentration in the fish body, resulting in the reduction of its toxic effects on the biochemical and antioxidant activities. These results demonstrated that dietary ILL supplementation could protect Nile tilapia against the toxic effects of HM, and therefore, may serve as a beneficial feed additive for application in the aquaculture industry.

Juniper leaf-like ZnO crystals synthesized through a melt oxidation of Al–Zn mixture in air

ZnO crystals with juniper leaf-like morphology were synthesized through simple one-step oxidation of Al–Zn mixture in air at atmospheric pressure. The juniper leaf-like ZnO crystals consisted of a (leaf stalk-like) main trunk and (leaf blade-like) many branches, which was similar to the shape of a juniper leaf. The trunk was several tens of micrometers in length and about 1.2 μm in thickness. The length and the thickness of the branches were several tens of micrometers and about 500 nm, respectively. The juniper leaf-like ZnO crystals exhibited a sharp visible emission.

NixZn1-xFe2O4 modified activated carbons from industrial waste as catalysts for hydrogen production

Abstract This study is aimed at the development of intelligent approach for clean energy production via valorization of industrial waste by-products. The proposed scheme is based on the preparation of activated carbon based catalysts for methanol decomposition as a source of hydrogen. Peach stones from the canning industry and by-products from low-rank coals treatment, all of them widely available in the Balkan region, are used as activated carbon precursors. The specific effect of carbon support on the formation of the loaded active NixZn1-xFe2O4 (x = 0; 0.2; 0.8; 1) ferrite phase are studied by nitrogen physisorption, XRD, HRTEM, FTIR, Moessbauer spectroscopy, TPR with hydrogen and Boehm method. To precise the discussion, analogues KIT-6 silica modifications are used as reference samples. It was found that the hosted in the activated carbon metal containing phase represents a complex mixture of Ni and/or Zn substituted magnetite, NiFe alloys, metallic Fe and ZnO. Its composition and dispersion is controlled by the variation of the Ni/Zn ratio and the texture peculiarities of the carbon support, the latter being easily tuned by the waste precursor used. The NixZn1-xFe2O4 modified activated carbons obtained from peach stones and coal treatment by-products possess a significant potential for sustainable environmental protection as cheap and effective catalysts for hydrogen production.

EFFECT OF SOME ORGANIC AND INORGANIC FERTILIZERS ON PLANT IRRIGATED BY SALINE WATER

The current study was carried out as a pot experiment at the Experimental Farm, Faculty of Agriculture, Menoufia University during winter growth season of 2015 -2016 to study the individual and combined effect of inorganic and organic fertilizations and Si application on barley plant irrigated by saline water under sandy soil conditions as well as sandy soil chemical properties and its content of available macro- and micronutrients and silicon. The used pots were divided into two main groups. The soil in the first main group no received farmyard manure (FYM) but the second one treated by FYM at rate of 3% . Both N and P fertilizers were add at its recommended doses. i.e 134 kg / fed and (200 kg/fed) at ammonium nitrate (33 % N) and super phosphate (15.5 % P2O5) respectively. The treatments of FYM and P were carried out and good mixed with sandy soil before planting. Foliar application of silicon was carried as potassium silicate 400 liter / fed 25% SiO2 + 10% K2O where foliar solution of micronutrients applications Foliar application of Fe , Zn and Mn mixture was carried at 400 liter / fed 12 % , 12% and 13 % respectively in EDTA form . The obtained data showed that, there are a significant increase in the dry matter yield (g /pot) of barley plants (shoots and roots) as a result of the studied treatments. Also , there are an increase in plant content of N , P, K, Fe , Mn , Zn and Si . The obtained data show also EC values in the soil treated by organic application were higher than that recorded with the initial soil before planting. On the other hand soil EC was decreased as a result of inorganic application alone. Also the pH and CaCO3 values and there were an increase in soil content of OM , CEC, N, P , K , Fe , Mn , Zn and Si.

Transient Liquid Phase Bonding of Ti-6Al-4V and Mg-AZ31 Alloys Using Zn Coatings.

Ti-6Al-4V and Mg-AZ31 were bonded together using the Transient Liquid Phase Bonding Process (TLP) after coating both surfaces with zinc. The zinc coatings were applied using the screen printing process of zinc paste. Successful bonds were obtained in a vacuum furnace at 500 °C and under a uniaxial pressure of 1 MPa using high frequency induction heat sintering furnace (HFIHS). Various bonding times were selected and all gave solid joints. The bonds were successfully achieved at 5, 10, 15, 20, 25, and 30 min. The energy dispersive spectroscopy (EDS) line scan confirmed the diffusion of Zn in both sides but with more diffusion in the Mg side. Diffusion of Mg into the joint region was detected with significant amounts at bonds made for 20 min and above, which indicate that the isothermal solidification was achieved. In addition, Ti and Al from the base alloys were diffused into the joint region. Based on microstructural analysis, the joint mechanism was attributed to the formation of solidified mixture of Mg and Zn at the joint region with a presence of diffused Ti and Al. This conclusion was also supported by structural analysis of the fractured surfaces as well as the analysis across the joint region. The fractured surfaces were analyzed and it was concluded that the fractures occurred within the joint region where ductile fractures were observed. The strength of the joint was evaluated by shear test and found that the maximum shear strength achieved was 30.5 MPa for the bond made at 20 min.

The structure and properties of the coating based on particles of copper and zinc deposited by gas-dynamic spraying

The results of the study of the structure and properties of the coating based on a particulate mixture of Cu and Zn deposited by the method of cold gas-dynamic spraying are presented. The presence of diffusion during the deposition of a coating with the formation of a solid solution of copper in zinc is shown. The process of predominant diffusion of copper into zinc with a slight exposure time in the furnace with the formation of intermetallic compounds Cu5 Zn8 and CuZn, the mass fraction of which reaches 44% and 28%, respectively, is revealed. The diffusion coefficient of copper to zinc is not less than 1.56×10−13 m2·s−1. An increase in the exposure time leads to a decrease in the content of beta (β ′ ) and gamma (γ) phases to ≈ 15% and the formation of a solid solution of zinc in copper (α phase, 58%) with a different ratio of initial components. The formation of electronic compounds reduces the cohesive strength of the coating metal by almost two times, and an increase in the proportion of the phase leads to an increase in the cohesion above the initial value.

Combined Toxicity of Nitro-Substituted Benzenes and Zinc to Photobacterium Phosphoreum: Evaluation and QSAR Analysis.

The single toxicity (IC50) of zinc (Zn) and 11 nitro-substituted benzenes to Photobacterium phosphoreum were determined, respectively. On basis of single toxicity, the joint toxicity of binary mixtures of Zn and 11 nitro-substituted benzenes at different Zn concentrations of 0.2 IC50, 0.5 IC50, and 0.8 IC50 were measured. The joint toxicity was evaluated by toxic unit (TU) and additive index (AI) methods. The results indicated that the joint toxicity was not only depending on the Zn concentrations but also on the substituted groups of nitro-substituted benzenes. The quantitative structure-activity relation (QSAR) equations were developed and the results showed that the toxicity of nitro-substituted benzenes has different joint effect at the different Zn concentrations. At the Zn concentration of 0.2 IC50, the binary joint effects were mainly antagonism and the joint toxicity was negatively related to descriptors called VE2_B(p) and TIC3. At the Zn concentration of 0.5 IC50 and 0.8 IC50, the binary joint effects were mainly antagonism and simple addition, and the joint toxicity was related to the same descriptor Eig06_ AEA(dm). It indicated that the joint toxic actions were similar when combined at the medium and high concentrations of Zn.

EFFECT OF FARMYARD MANURE ON BARLEY PLANTS RESPONSE TO FOLIAR APPLICATIONS OF MICRONUTRIENTS AND SILICON IN SANDY SOIL IRRIGATED BY SALINE WATER

A pot experiment was carried out at the Experimental Farm, Faculty of Agriculture, Menoufia University, Shebin El-kom, Egypt during winter growth season of 2015/ 2016 to study the effect of foliar applications of silicon (Si) and micronutrients ( Fe, Mn and Zn ) individually and combined without and with farmyard manure ( FYM ) on barley plant (Hordeum Vulgare L ) irrigated by saline water under sandy soil conditions. Surface soil sample (0-20cm) representing sandy soil was collected from a private farm at 60 km North Cairo and far about one km east of Cairo - Alexandria Desert high away. Farmyard manure was added at a rate of 3% before sowing. Foliar application of silicon was carried as potassium silicate (25% SiO2 + 10% K2O) where foliar solution of micronutrients of Fe, Zn and Mn mixture (12 % , 12% and 14 % respectively) in EDTA form. The final volume of foliar solutions was 400 liter /fed. Applications of F1, F2 and F1+F2 were carried out after 35 days of sowing. The obtained data showed that individual and combined applications of F1 and F2 without and with FYM resulted in a significant increases of dry matter yields ( g/pot ) of both roots and shoots of barley plants, where the highest values was resulted with the combined treatment of FYM +F1+F2 followed by that resulted from the treatment of F2 +F2.Also,the high contents and uptake of N, P, K, Fe , Mn , Zn and Si by both roots and shoots of barley plants were resulted from the treatment of F1+F2 with FYM. So, all relative changes ( RC , % ) values of macro- and micronutrients and silicon uptake by barley plants ( roots and shoots ) at age 42 and 70 days were positive . From the obtained data may be concluded that , under sandy soil conditions using saline water for irrigation , organic manures and foliar applications of Fe , Mn , Zn and Si is very important to increase plant growth and decrease the harmful effect of salinity stress .

Structural Analysis and Growth Mechanism of Zn/ZnO Nanowires in AAO Template by Electrodeposition

To fully understand the mechanism of forming Zn and ZnO nanowires in electrodeposition, Anodic Alumina Oxide (AAO) membrane was used to electrodeposit Zn/ZnO nanowires by varying the potential. The structure of electrodeposited Zn/ZnO nanowires is studied by means of X-ray diffraction and scanning electron microscopy. Different deposition parameters were used to obtain different structure of electrodeposited nanowires. At -1.4 V with pH2.5, the pure Zn nanowires are electrodeposited. By lowering the potential to -1.0 V with same electrolytic concentration and pH, the formed nanowires are mixture of Zn and ZnO. Further decrease in potential to -0.6V, electrodeposited nanowires are of pure ZnO. The size of the critical cluster decreases with increasing the over potential. The formation of pure ZnO nanowires can be attributed to the formation of large size critical Zn nuclei, the larger size of nuclei favors the formation of pure zinc oxides nanowires.

Thermoelectric Properties of Zn4Sb3 Composites with Incomplete Reaction

Zn4Sb3 composites have been prepared by plasma-activated sintering (PAS) using mixtures of Zn and Sb. Small amounts of ZnSb and Zn were found as impurity phases. Scanning electron microscopy revealed that metallic Zn was present along the particle boundaries. A sudden decline in the thermal conductivity was found at ∼ 600 K. However, this phenomenon disappeared after the application of heat treatment for 4 h. Further studies confirmed that this decline in the thermal conductivity is related to the reaction between ZnSb and Zn. The dynamic change in the structure during the reaction reduced the thermal conductivity and improved the thermoelectric performance of the Zn4Sb3 composites.

Synthesis and Optical Properties of Solid and Hollow ZnO Microspheres Prepared by Hydrothermal Method

We successfully synthesized solid and hollow ZnO microspheres by a template-free hydrothermal method on the substrate of porous alumina membranes. The morphology of prepared sample was characterized by scanning electron microscopy and transmission electron microscopy. The growth mechanism of the synthesized ZnO microspheres is discussed in detail. At step 1, solid ZnO microspheres were prepared by the thermal decomposition of the Zn(OH)2 microspheres synthesized under the mixture of Zn(NO3)2·6H2O, C6H12N4, and C6H5Na3O7·2H2O solution. The quantity of C6H5Na3O7·2H2O dopant will greatly affect the morphology of the prepared sample by controlling ZnO nucleation and growth rate. At step 2, hollow ZnO microspheres were prepared by removing the Zn(OH)2 cores in an alkaline solution. The proper pH value also plays a key role in preparing hollow ZnO microspheres with high quality. Compared with hollow nanostructure, the solid ZnO microsphere shows the relatively strong Raman peaks at 437 cm-1, which suggests that the prepared solid spheres should have the better crystal quality. Photoluminescence spectra show that the solid ZnO microspheres have the relatively strong ultraviolet (UV) peak at ~ 380 nm attributed to the recombination of free exciton, and the weak green peak owing to the low surface-to-volume ratio. DOI: http://dx.doi.org/10.5755/j01.ms.24.4.19141

Plasma-assisted synthesis of ZnSe hollow microspheres with strong red emission

We demonstrate the growth of ZnSe microspheres in large quantities by using a mixture of Zn and Se as precursors via direct current arc discharge method without the addition of any catalyst or template. The as-obtained samples were characterized by X-ray diffraction, Raman, energy-dispersive X-ray spectrometry, scanning and transmission electron microscopy, and ultraviolet-visible reflectance spectroscopy. The majority of the ZnSe microspheres which were composed of ZnSe nanoparticles exhibited perfectly spherical morphology and a distinct hollow structure with a relatively rough surface. The growth mechanism of ZnSe hollow microspheres has been discussed. Room-temperature excitation and emission spectra as well as the fluorescence lifetime of ZnSe hollow microspheres were measured and the results showed ZnSe hollow microspheres exhibit an intensive wide broad emission bands from 550 to 750 nm upon 470 nm excitation with fast decay time 1.09 ms and CIE chromaticity coordinates (0.65, 0.34), which was ascribed to characteristic structure defects (vacancies and interstitials) in ZnSe. Additionally, the temperature dependent emission behavior was measured and discussed.

Morphological Change and Luminescence Properties of ZnO Crystals Synthesized by Thermal Evaporation of a Mixture of Zn and Cu Powder

ZnO crystals with different morphologies are synthesized through thermal evaporation of the mixture of Zn and Cu powder in air at atmospheric pressure. ZnO crystals with wire shape are synthesized when the process is performed at 1,000 °C, while tetrapod-shaped ZnO crystals begin to form at 1,100 °C The wire-shaped ZnO crystals form even at 1,000 °C, indicating that Cu acts as a reducing agent. As the temperature increases to 1,200 °C, a large quantity of tetrapod-shaped ZnO crystals form and their size also increases. In addition to the tetrapods, rod-shaped ZnO crystals are observed. The atomic ratio of Zn and O in the ZnO crystals is approximately 1:1 with an increasing process temperature from 1,000 °C to 1,200 °C For the ZnO crystals synthesized at 1,000 °C, no luminescence spectrum is observed. A weak visible luminescence is detected for the ZnO crystals prepared at 1,100 °C Ultraviolet and visible luminescence peaks with strong intensities are observed in the luminescence spectrum of the ZnO crystals formed at 1,200 °C

Effects of zinc acetate and cucurbit[6]uril on PP composites: crystallization behavior, foaming performance and mechanical properties

Abstract In this study, polypropylene (PP) foams were prepared with 1.0 wt% of cucurbit[6]uril (Q[6]), zinc acetate (Zn(Ac)2), Zn@Q[6] (a supramolecular compound synthesized from Q[6] and Zn(Ac)2), or a mixture of Zn(Ac)2 and Q[6] (weight ratio of 1:1) through injection molding in the presence of a chemical blowing agent, azodicarbonamide. The effect of the additions on the crystallization behavior and foaming performance of PP and the mechanical characterizations of the foaming samples were determined. The results showed that the additions can change the crystallization type from homogeneous to heterogeneous, increase the crystallization rate and shrink the size but increase the density of spherulites. Among the additions, Q[6] most significantly altered the crystallization properties. Scanning electron microscopy (SEM) images revealed that the PP foaming performance can be improved by Zn(Ac)2 addition at a lower temperature (175°C); however, further increasing the temperature had an undesirable effect. Q[6] exhibited the optimum foaming improvement effect on PP in a wide temperature range (175–195°C). Adding nanoparticles also enhanced the tensile properties, flexural strength and impact strength of foaming PP at low temperatures. However, with increasing temperature, the poor cell structure demonstrated undesirable effects in terms of tensile strength, flexural strength and impact strength.

Excellent microwave absorption of FeCo/ZnO composites with defects in ZnO for regulating the impedance matching

FeCo/ZnO composites have been successfully prepared through liquid-phase reduction process for the formation of FeCo polyhedrons and sequentially thermal decomposition of colloidal mixture of FeCo and Zn(Ac)2·2H2O under nitrogen atmospheres. ZnO nanoparticles are homogeneously deposited on the surface of FeCo polyhedrons and the level of oxygen-vacancy defects in ZnO can be elevated with the increase of ZnO content. By comparison with FeCo polyhedrons, FeCo/ZnO composites exhibit excellent microwave absorption. The optimal RL value can reach −34.8 dB at 14.8 GHz and effective bandwidth (RL < −10 dB) is 5.1 GHz in the frequency range of 12.4–17.5 GHz with a matching thickness of 1.5 mm. The integrated bandwidth with RL < −10 dB can reach 14.1 GHz covering 3.4–17.5 GHz. Theory analysis demonstrates the interfacial polarization, dipole polarization and high conductivity due to oxygen-vacancy defects in FeCo/ZnO composites contribute to enhancement of dielectric loss capacity, which is more favorable for impedance matching.