Zn Powder Research Articles

Synthesis, Anticancer Activity, Structure‐Activity Relationship and Mechanistic Investigations of Falcarindiol Analogues

Forty samples of optically active falcarindiol analogues are synthesized by using the easily available C2 symmetric (R)- and (S)-1,1'-binaphth-2-ol (BINOL) in combination with Ti(Oi Pr)4 , Zn powder and EtI. Their anticancer activities on Hccc-9810, HepG2, MDA-MB-231, Hela, MG-63 and H460 cells are assayed to elucidate their structure-activity relationships. These results showed that the falcarindiol analogue (3R,8S)-2 i with the terminal double bond has the most potent anti-proliferation effect on Hccc-9810 cells with IC50 value of 0.46 μM. The falcarindiol analogue (3R,8S)-2 i can induce obvious Hccc-9810 cell apoptosis in a concentration-dependent manner by Hoechst staining and flow cytometry analysis. The proposed mechanism suggests that the falcarindiol analogue (3R,8S)-2 i increases LDH release and MDA content, and reduces the levels of SOD activity, which lead to the accumulation of oxidative stress and induce apoptosis in Hccc-9810 cells.

Toward a Practical Zn Powder Anode: Ti3C2Tx MXene as a Lattice-Match Electrons/Ions Redistributor.

The renaissance of aqueous Zn ion batteries has drawn intense attention to Zn metal anode issues, including dendrites growth, dead Zn, low efficiency, and other parasitic reactions. However, against the widely used 2D Zn foil, in fact, the Zn powder anode is a more practical choice for Zn-based batteries in industrial applications, but the related solutions are rarely investigated. Herein, we focus on the Zn powder anode and disclose its unknown failure mechanism different from Zn foils. By utilization of 2D flexible conductive Ti3C2Tx MXene flakes with hexagonal close-packed lattice as electrons and ions redistributor, a stable and highly reversible Zn powder anode without dendrite growth and low polarization is constructed. Low lattice mismatch (∼10%) enables a coherent heterogeneous interface between the (0002) plane of deposited Zn and (0002) plane of the Ti3C2Tx MXene. Thus, the Zn2+ ions are induced to undergo rapid uniform nucleation and sustained reversible stripping/plating with low energy barriers via the internally bridged shuttle channels. Paired with cyano group iron hexacyanoferrate (FeHCF) cathode, the FeHCF//MXene@Zn full battery delivers superior cycle durability and rate capability, whose service life with a CE of near 100% touches 850% of bare Zn powder counterparts. The proposed Ti3C2Tx MXene redistributor strategy concerning high-speed electrons/ions channel, low-barrier heterogeneous interface, is expected to be widely applied to other alkali metal anodes.

Corrosion Behavior of Zn, Fe and Fe-Zn Powder Materials Prepared via Uniaxial Compression.

Powder metallurgy is one of the most prevalent ways for metallic degradable materials preparation. Knowledge of the properties of initial powders used during this procedure is therefore of great importance. Two different metals, iron and zinc, were selected and studied in this paper due to their promising properties in the field of biodegradable implants. Raw powders were studied using scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDX). Powders (Fe, Zn and Fe-Zn in a weight ratio of 1:1) were then compressed at the pressure of 545 MPa to the form of pellets with a diameter of 1.7 cm. Surface morphology and degradation behavior in the Hanks´ solution were studied and evaluated. Electrochemical polarization tests along with the static immersion tests carried out for 21 days were employed for corrosion behavior characterization. The highest corrosion rate was observed for pure Zn powder followed by the Fe-Zn and Fe, respectively. A mixed Fe-Zn sample showed similar properties as pure zinc with no signs of iron degradation after 21 days due to the effect of galvanic protection secured by the zinc acting as a sacrificial anode.

Optical and radioluminescence properties of ZnO:Zn as a function of reduction degree and treatment temperature

The aim of this work is to highlight the correlation between treatment conditions, composition, and structure of reduced zinc oxide (ZnO:Zn) with optical and radioluminescence properties for the production of high yield scintillating powders. Purchased zinc oxide (ZnO) powders (≈0.35 ± 0.15 μm) were thermally reduced in Ar/H2 (3%) atmosphere at temperatures ranging between 600 (≈0.40 ± 0.17 μm) and 1000 °C (≈6.4 ± 1.6 μm), obtaining ZnO:Zn powders. The reduction degree, evaluated through energy dispersive spectroscopy, showed a linear increase from 0% up to 20% (800 °C sample), reaching a plateau condition at about 25% for the highest treatment temperatures (1000 °C sample). Structural analysis highlighted the existence of a threshold temperature, previously reported in the literature, around 800 °C, beyond which (i) the grain size remarkably increases, (ii) the shape changes from hexagonal to round-shaped, and (iii) the intensity of electron spin resonance (ESR)-active defects at g = 1.9596 decreases for a new resonance at g = 2.0105. Additionally, a substantial variation, from 5.63 ± 0.02 down to 5.2 ± 0.1 g/cm3, of the skeletal density and a slight contraction of the optical bandgap are observed. Unlike the structural properties, PL and x-ray radioluminescence showed a continuous increase of the green emission intensity, associated with ESR-active ionized oxygen vacancies and ESR non-active recombination centers, and of the PL defective lifetimes (33 ns < τfast < 88 ns, 395 ns < τslow < 930 ns).

Thermal Evaporation Synthesis of Vertically Aligned Zn2SnO4/ZnO Radial Heterostructured Nanowires Array.

The construction of a heterostructured nanowires array allows the simultaneous manipulation of the interfacial, surface, charge transport, and transfer properties, offering new opportunities to achieve multi-functionality for various applications. Herein, we developed facile thermal evaporation and post-annealing method to synthesize ternary-Zn2SnO4/binary-ZnO radially heterostructured nanowires array (HNA). Vertically aligned ZnO nanowires array (3.5 μm in length) were grown on a ZnO-nanoparticle-seeded, fluorine-doped tin oxide substrate by a hydrothermal method. Subsequently, the amorphous layer consisting of Zn-Sn-O complex was uniformly deposited on the surface of the ZnO nanowires via the thermal evaporation of the Zn and Sn powder mixture in vacuum, followed by post-annealing at 550 °C in air to oxidize and crystallize the Zn2SnO4 shell layer. The use of a powder mixture composed of elemental Zn and Sn (rather than oxides and carbon mixture) as an evaporation source ensures high vapor pressure at a low temperature (e.g., 700 °C) during thermal evaporation. The morphology, microstructure, and charge-transport properties of the Zn2SnO4/ZnO HNA were investigated by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and electrochemical impedance spectroscopy. Notably, the optimally synthesized Zn2SnO4/ZnO HNA shows an intimate interface, high surface roughness, and superior charge-separation and -transport properties compared with the pristine ZnO nanowires array.

COLD-SPRAYED Al-COMPOSITE COATINGS ON S135 DRILL-PIPE STEEL

Nine kinds of Al-composite coatings were cold sprayed on the S135 steel. The mechanical properties and microstructures of the coatings were analyzed and the corrosion behavior of the coatings was studied. The surface morphology of the coatings was observed. The porosity of the nine coatings was less than 1.52 %. A proper increase in the Zn powder could reduce the porosity. The thickness of a coating could be increased with an increase in Al2O3 and Zn. The hardness of a coating increased obviously after adding Al2O3. The friction coefficient of a coating decreased with the increase in Zn and Al2O3. The corrosion rate of the coatings decreased with an increase in Al and Al2O3.

The Synthesis of Long Decorated ZnO Column by Chemical Vapor Deposition Technology

In this work, long decorated ZnO columns were synthesized by a chemical vapor deposition method. Co(NO3)2 alcohol solution was added into the Zn powder and used as the active sites for the formation of ZnO. The prepared ZnO morphology was influenced by the deposition temperature, higher deposition temperature facilitated the formation of long ZnO column decorated with short ZnO columns. And also, the size of decorating ZnO column increased as the deposition temperature increased, the optical properties of prepared ZnO sample will be influenced due to the decreased active sites. The findings will be conducive to the development of ZnO-based optoelectronic devices.

Development of Mg-based biodegradable composite using friction stir processing for orthopedic application

The latest research shows the construction of a biodegradable composite based on magnesium (Mg-Zn-Mn) by means of friction mixing. The Zn and Mn micro powder parts were enhanced to increase corrosion resistance and mechanical properties on a surface dependent on Mg-alloy. The microstructure and mechanical properties have been studied for their influence on various forms of FSP process parameters: tool-geometry (Tg), movement speed (TS) and rotations speed (Rs). The analysis of the Mg-based composite as formed has been investigated with microstructure, elemental and phase composition. The Vickers' micro-hardness tester and universal testing machine calculated the micro-hardness and tensile strength of the as formed Mg-based composite (UTM, BIS). The microstructural test showed that a Mg-base composite with a coarse grain size range of approximately 25 μm was also distributed with the reinformed material in the matrix. The mechanical properties are tensile resistance (UTS) of 125 MPa with an elongation percentage of 13.47 percent and are smaller than the young 35 MPa modulus near the cortical bone of the cortical bone.

Recent Advances in the Plasma-Assisted Synthesis of Zinc Oxide Nanoparticles

An overview of recent work on the low-temperature plasma-assisted synthesis of zinc oxide (ZnO) nanoparticles is presented and interpreted in terms of gas-phase and surface reactions with illustrated examples. The thermodynamical nonequilibrium conditions allow the formation of chemically reactive species with a potential energy of several eV, which readily interact with the Zn precursors and initiate reactions leading to the formation of nanoparticles or nanowires. The high-quality nanowires were synthesized from Zn powders only upon interaction with moderately ionized plasma in a narrow range of plasma parameters. This technique is promising for the synthesis of large quantities of nanowires with aspect ratios well above 10, but the exact range of parameters remains to be determined. Apart from the ex situ techniques, the ZnO nanoparticles can be synthesized by depositing a film of precursors (often Zn salts or Zn-containing organometallic compounds) and exposing them to oxygen plasma. This technique is useful for the synthesis of well-adherent ZnO nanoparticles on heat-sensitive objects but requires further scientific validation as it often leads to the formation of a semicontinuous ZnO film rather than nanoparticles. Both low-pressure and atmospheric plasmas are useful in converting the precursor film into ZnO nanoparticles despite completely different mechanisms.

Tuning the Sheet Resistance, Ferromagnetism, and H2O2 Sensitivity of ITO Film by Introducing Tunable Pores

An ethanol-assisted etching route using Zn powder as reductant was developed to prepare the tunable pores in ITO films for modifying the sheet resistance, ferromagnetism, and H2O2 sensitivity. Both...

Effect of Powder Particle Concentration and Tool Electrode Material amid Zinc Powder-Mixed µEDM of Biocompatible Mg Alloy AZ91D

Magnesium (Mg) alloys exhibit high strength and biocompatibility, coupled with a unique characteristic that is the ability to degrade over time. These characteristics of Mg alloys led to the development of several biodegradable medical implants such as screw, pin, and plate. Powder-mixed micro-electric discharge machining (PM-μEDM) was found to substantially improve the surface and metallurgical properties of biodegradable alloys and therefore, it was used in this study to investigate the machinability of Mg alloy AZ91D. PM-μEDM was performed at varying zinc (Zn) powder particle concentrations (0 to 8 g/l) using copper and brass tool electrodes. The effect of these input control variables on the machining time, dimensional deviation, and characteristics of the machined surface was experimentally examined. The machined surfaces were primarily analyzed by field-emission scanning electron microscope, energy-dispersive spectrometry, and x-ray diffraction (XRD). The findings showed a significant reduction in the machining time and dimensional deviation during PM-μEDM at 4 g/l powder particle concentration using the copper tool electrode. Moreover, the presence of resolidified debris, powder particles, and formed metal oxides and carbides in the recast layer, produced with the aid of the copper tool electrode at 4 g/l powder particle concentration, exhibited a considerable surface modification.

Green Synthesis of Luminescent Gold-Zinc Oxide Nanocomposites: Cell Imaging and Visible Light-Induced Dye Degradation.

Green synthesis of gold-zinc oxide (Au-ZnO) nanocomposite was successfully attempted under organic solvent–free conditions at room temperature. Prolonged stirring of the reaction mixture introduced crystallinity in the ZnO phase of Au-ZnO nanocomposites. Luminescence properties were observed in these crystalline Au-ZnO nanocomposites due to in situ embedding of gold nanoparticles (AuNP) of 5–6 nm diameter on the surface. This efficient strategy involved the reduction of Au(III) by Zn(0) powder in aqueous medium, where sodium citrate (NaCt) was the stabilizing agent. Reaction time and variation of reagent concentrations were investigated to control the Au:Zn ratio within the nanocomposites. The reaction with the least amount of NaCt for a long duration resulted in Au-ZnO/Zn(OH)2 nanocomposite. X-ray photoelectron spectroscopy (XPS) confirmed the formation of Zn(OH)2 and ZnO in the same nanocomposite. These nanocomposites were reconnoitered as bioimaging materials in human cells and applied for visible light–induced photodegradation of rhodamine-B dye.

Study on Coating Material and Preparation Technology of Aluminum Alloy Tube by Low Temperature Self-Propagating Molding

Low temperature self-propagating forming coating material system for aluminum alloy cylinder parts was designed with Al, Fe2O3, Mo, Cu, Ni and Ti powders as raw materials. Low temperature self-propagating wear-resistant coating was prepared on the inner wall of aluminum alloy cylinder parts by thermal spraying ignition condensation centrifugal self-propagating fusion technology. XRD, DSC and SEM were used to study the microstructure, thermodynamic properties and cross-section morphology of the coating after thermal reaction of four kinds of low-temperature self-propagating materials with different proportions. The preparation process parameters of the coating were optimized by orthogonal test, including the amount of coating, the rotation speed of self-propagating centrifuge and the reaction time of self-propagating coating. The results show that the addition of Si, Mo and Zn powders in the four low temperature self-propagating powder systems can reduce the occurrence temperature of aluminothermic reaction; the optimal process parameters for coating preparation are rotational speed of 2000r/min, powder filling amount of 0.9g/cm3 and rotational reaction time of 16S.The results show that the coating with 20wt.% Al, 60wt.% Fe2O3, 12wt.% Si, 4wt.% Mo and 4wt.% Zn has better density and interface adhesion.

Developing composites of zinc and hydroxyapatite for degradable orthopedic implant applications

In the present work, Zn-HA composites were developed by powder metallurgy route targeted for bone implant applicaitons. Zn-HA powders with varying HA content (1, 2, and 4 wt.%) were ball milled for 1 hr and sintered to produce composite compacts. X-ray diffraction (XRD) studies were done for all the ball milled powders and sintered compacts. No impurities were observed in the ball milled powders. Microstructural observations revealed the formation of lamellar structure in the composites due to the plastic deformation of the Zn powders during ball milling. Grain size measurements revealed the decreased grain size with increase of addition of HA. Furthermore, aspect ratio (length to thickness ratio) of the grains was measured and found that the aspect ratio was also decreased with the increased HA content. Higher microhardness was measured for all the composites compared with pure Zn. However, composite with 1% has shown higher hardness compared with the remaining composites. Form the preliminary observations, it can be concluded that Zn-HA composites can be successfully produced with lamellar morphology by ball milling followed by sintering for biomedical applications with increased hardness.

The effect of zinc shape on its corrosion mitigation as an anode in aqueous Zn/MnO2 battery

• Developing of Zn powder and dust electrode for aqueous Zn/MnO 2 battery. • Zn powder with grain sizes >500 µm attenuate its corrosion and dissolution in NH 4 Cl solution. • Assembling of Zn powder or dust (anode) with electrolytic (EMD) or nanostructured (NMD) MnO 2 (cathode) in Zn/MnO 2 cell. • Zn powder (>500 µm)/NMD cell yields a highest output voltage of 1.646 V. • Specific energy (109.722 mWh/g) and the lowest voltage drop of 0.7% after 2 h of discharge. This work gives an insight into how zinc (Zn) anode in the Zn/MnO 2 batteries is corroded depending on its shape (in the form of powder or dust), and how such shape can play a role to attenuate the Zn corrosion and dissolution during an electrochemical process. Indeed, the corrosion of Zn anodes in powder and dust shape was investigated in ammonium chloride aqueous NH 4 Cl solution using open circuit potential (OCP) plot, linear polarization (LP), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) methods. The electrodes were also observed by scanning electron microscopy (SEM) and analyzed using X-ray diffraction (XRD). The results show that the corrosion rate significantly depends on Zn grain size and surface area. In addition, the SEM observations showed clearly some corrosion features on the surface of Zn grains. Furthermore, the XRD analysis confirms the formation of a corrosion layer constituted of ZnO and adsorbed Zn(NH 3 ) 2 Cl 2 molecules. These electrodes, with two distinct shapes, were used as anodes in assembled Zn/MnO 2 batteries with two types of MnO 2 cathode namely nanostructured manganese dioxide (NMD) and electrolytic manganese dioxide (EMD). Discharge tests showed high performance for Zn/MnO 2 cell based on Zn powder (>500 µm) as anode and NMD as a cathode in NH 4 Cl electrolyte, with an output voltage of 1.65 V and specific energy of 109.72 mWh/g after 2 h under 1 mA. Moreover, this cell is the most stable with a voltage drop as low as 0.7% after 2 h of continuous discharge. Such results demonstrate that the assembled Zn/MnO 2 can be used for low cost and high-performance battery with a specific structure and shape of both anode and cathode materials.

Phase formation and thermoelectric properties of Zn1+Sb binary system

The phase formation and thermoelectric (TE) properties in the central region of the Zn−Sb phase diagram were analyzed through synthesizing a series of Zn1+xSb (x=0, 0.05, 0.1, 0.15, 0.25, 0.3) materials by reacting Zn and Sb powders below the solidus line of the Zn−Sb binary phase diagram followed by furnace cooling. In this process, the nonstoichiometric powder blend crystallized in a combination of ZnSb and β-Zn4Sb3 phases. Then, the materials were ground and hot pressed to form dense ZnSb/β-Zn4Sb3 composites. No traces of Sb and Zn elements or other phases were revealed by X-ray diffraction, high resolution transmission electron microscopy and electron energy loss spectroscopy analyses. The thermoelectric properties of all materials could be rationalized as a combination of the thermoelectric behavior of ZnSb and β-Zn4Sb3 phases, which were dominated by the main phase in each sample. Zn1.3Sb composite exhibited the best thermoelectric performance. It was also found that Ge doping substantially increased the Seebeck coefficient of Zn1.3Sb and led to significantly higher power factor, up to 1.51 mW·m−1·K−2 at 540 K. Overall, an exceptional and stable TE figure of merit (ZT) of 1.17 at 650 K was obtained for Zn1.28Ge0.02Sb.

Comparison of Performance and Microstructure of Two Kinds of Cold Spray Anticorrosion Composite Coatings on High-strength Steel

Objective to study the performance of Zn/Ni composite coatings and Al/Zn composite coatings, which were deposited by Cold Gas Dynamic Spray. Methods: Those coatings was sprayed by Zn and Ni mixture powder and Al and Zn mixture powder on 300M high-strength steel surface, the SEM images and micro hardness tester analyzed the two kinds coatings’ morphology and microstructure. The corrosion resistance of Zn/Ni coatings can be compare with Al/Zn coatings, which was investigated by neutral salt-spray test and coating furcated test. Results The results indicate that Zn/Ni coatings porosity is 0.8%, it is same as Al/Zn coatings. The micro hardness of Zn/Ni coatings is 70.8HV, which is higher than Al/Zn coatings 61.2HV. However, the salt spray result of Al/Zn coatings can reach 1000h and it can reach 770h even the coatings fails; which is better than Zn/Ni coatings, their salt spray resistance can reach 770h and it can reach 350h when the coatings fails. Conclusion those coatings could both be efficient corrosion resistance coatings on 300M high strength steel surfaces.

Calendar Life of Zn Batteries Based on Zn Anode with Zn Powder/Current Collector Structure

AbstractZn foil is widely used for studying the stability and dendrite formation behavior of Zn anodes. The reported long cycling life of rechargeable Zn batteries (RZBs) is obtained by testing a battery immediately after its fabrication neglecting the aging effects. The cycling performance demonstrated cannot, however, have practical applications. Using Zn foil as both the working electrode and current collector will cause many problems when the battery is scaled up. A Zn powder (Zn‐P)/current collector configuration is more practical. In this work, the corrosion of the Zn‐P@Cu anode‐induced cell swelling is first quantitatively studied. During the aging process of the Zn‐P@Cu electrode, hydrogen forms on the surface of Cu and the Zn‐P dissolves resulting in morphological changes. These phenomena can be attributed to galvanic corrosion between Cu and Zn. To address this issue, tin with a higher overpotential for hydrogen generation is plated on Cu surface. The results indicate that hydrogen evolution is ameliorated. With a low NP ratio (mass) of 10:7, considerably better storage and cycling performance are achieved for Zn‐P@Cu//MnO2. These results highlight the need to focus on the calendar life of RZBs and corrosion of the Zn anode.

Characterization of Aluminum Powders: IV. Effect of Nanometals on the Combustion of Aluminized Ammonium Nitrate‐Based Solid Propellants

AbstractThis study is devoted to the investigation of the energetic properties of two types of aluminized solid propellants with inert and active binders modified by additives of six different metal nanopowders. The substitution of an inert binder for the active one resulted in significant improvement of energetic properties. However, burning rate regulation become more complicated because the pressure exponent in burning rate law was increased as well. The DSC analysis revealed that the most significant catalytic effects were observed while using Zn, Cu, and Mo powders. Combustion of compositions based on an inert combustible binder and ammonium nitrate was studied in the pressure range 0.1–10.0 MPa. Due to the low combustion rate, no dispersion of burning aluminum particles was observed. During combustion, a single agglomerate of aluminum particles was formed, the mass of which was about 96 % of the initial aluminum mass in the formulation. A comparative analysis of nanosized metal additive effect on the propellant's combustion process was performed. It had been found that the activity of the metal nanopowders depends on the propellant formulation. It had been shown that Al and Zn did not affect the combustion rate of propellant with inert binder but they were effective in compositions with an active binder. Cu and Ni were found to be a good catalyst for the ammonium nitrate and active binder decomposition.

Mechanochemical Ignition of Self-propagating Reactions in Zn-S Powder Mixtures

The present work examines the mechanochemical reactivity of Zn-S powder mixtures subjected to mechanical processing by ball milling. Chemical composition, collision energy, powder charge inside the reactor, number of milling balls, Zn microstructure and temperature have been systematically varied to gain detailed information on the physical and chemical responses of reactant powders. It is shown that the mechanical activation of mixtures with intermediate Zn contents determines the ignition of self-sustaining high-temperature reactions that lead to the α and β ZnS line compounds and residual unreacted elements. Within the intermediate compositional range, ignition time decreases as the impact energy, the number of milling balls and the temperature increase and as the mass of powder decreases. In contrast, ignition times decrease as the hardness of Zn powder increases. Experimental findings are interpreted with the help of a phenomenological kinetic model.