Increasing Nickel Content Research Articles

Synthesis, characterization, and co-delivery of doxorubicin and melittin-loaded NiyMg1-yFe2O4 nanoparticles for combination therapy in MCF-7 and NIH-3T3 cell lines

The present investigation reporting about the synthesis of NiyMg1-yFe2O4 (y = 0.3, 0.5, and 0.7) nanoparticles employing the co-precipitation method. TG-DT analysis revealed that NiyMg1-yFe2O4 nanoparticles were thermally stable above 386 °C. Structural, morphological, and magnetic studies were carried out through XRD, FTIR, FESEM, HRTEM, and VSM tools. XRD analysis confirmed that the nanoparticles possessed a single-phase cubic spinel structure and the Debye-Scherrer equation employed notices a linear increase in average crystallite size with increases in both nickel concentration and annealing temperatures. Two prominent absorption peaks between 423 and 556 cm−1, observed in FTIR study corresponding to the stretching vibration of octahedral (B) and tetrahedral (A) sited characteristic of spinel ferrite. The surface morphology of the NiyMg1-yFe2O4 nanoparticles annealed at 600 °C was characterized through FESEM and HRTEM tools. FESEM micrographs emphasized a spherical shape with less agglomeration, while EDX spectra confirmed the presence of Fe, Ni, Mg, and O in the nanoparticles advocating its purity. HRTEM images further confirmed the spherical morphology of the nickel magnesium ferrite nanoparticles. Magnetic properties were measured using VSM technique, suggesting the saturation magnetization and coercivity values increased with increased nickel concentrations, showing its soft ferrimagnetic behavior and suggesting potential applications in drug delivery and storage devices. The in vitro investigation was carried out using MTT assay to ascertain the amount of cytotoxicity present in breast cancer (MCF-7) and non-cancerous (NIH-3T3) cells taken for study with help of prepared nanoparticles administered with drugs doxorubicin (DOX) and melittin (MLT).

Effect of Nickel Impurities in Pyrite on Catalytic Degradation of Thiosulfate

The effects of nickel content in nickel-bearing pyrite on photocatalytic properties, light absorption properties, and oxidative decomposition of thiosulfate were studied. The leaching experiments show that the consumption of thiosulfate in the Cu2+-ethylenediamine (en)-S2O32− system increases with an increase in nickel content in nickel-bearing pyrite. The consumption of Cu(en)22+ initially increases and then decreases with an increase in leaching time. There is a clear correlation between the change trend in its consumption and the doping amount of nickel in pyrite. The XPS results show that in the Cu2+-ethylenediamine (en)-S2O32− leaching gold system (temperature 25 °C, time 35 h, solution: 0.1 mol/L S2O32−, 5 mmol/L Cu(en)22+, 200 mL solution), the nickel of pyrite-containing nickel can be transferred to the leaching solution and becomes nickel ion. In this leaching system, Cu(II), which was originally complexed with en, is reduced to Cu(I) in a short time. The consumption of Cu(en)22+ increased rapidly in the 5 h period and then decreased gradually after 5 h. The results showed that the presence of free Ni2+ in the solution facilitated the conversion of bivalent copper ions to monovalent copper ions. Free Ni2+ ions can compete with Cu2+ ions for en ligands. When ethylenediamine complexes with Ni2+, the decomposition of Cu(en)22+ into Cu(en)+ and en occurs more rapidly. And the en, which was originally to be oxidized with Cu(en)+ to form Cu(en)22+, forms Ni(en)22+. As a result, the concentration of Cu(en)22+ continues to decrease in a short period of time.

Dual Modification Strategy for Enhanced Cycling and Rate Performance of Ni-Rich Cathode Materials in Lithium-Ion Batteries.

A great challenge in the commercialization process of layered Ni-rich cathode material LiNixCoyMn1-x-yO2 (NCM, x ≥ 80%) for lithium-ion batteries is the surface instability, which is exacerbated by the increase in nickel content. The high surface alkalinity and unavoidable cathode/electrolyte interface side reactions result in significant decrease for the capacity of NCM material. Surface coating and doping are common and effective ways to improve the electrochemical performance of Ni-rich cathode material. In this study, an in situ reaction is induced on the surface of secondary particles of NCM material to construct a stable lithium sulfate coating, while achieving sulfur doping in the near surface region. The synergistic modification of lithium sulfate coating and lattice sulfur doping significantly reduced the content of harmful residual lithium compounds (RLCs) on the surface of NCM material, suppressed the side reactions between the cathode material surface and electrolyte and the degradation of surface structure of the NCM material, effectively improved the rate capability and cycling stability of the NCM material.

Microstructural, magnetic, and optical properties of nickel-doped spinel zinc ferrite nanoparticles

This study focuses on the synthesis of nickel-substituted zinc ferrite nanoparticles, , via the sol-gel method and examines how nickel substitution influences their structural, magnetic, and optical properties. The lattice constant of the nanoparticles, which varied from 8.4296 Å to 8.4212 Å, decreased as the nickel concentration increased. Scanning electron microscopy (SEM) was employed to examine the morphology, revealing grain sizes between 46 and 53 nm, while energy dispersive X-ray spectroscopy (EDX) confirmed the elemental composition, showing nearly spherical nanoparticles containing all the constituent elements. The magnetic properties were analyzed using a vibrating sample magnetometer (VSM), which highlighted significant differences between the theoretical and experimental magnetic moments, indicating the presence of Yafet-Kittel magnetic ordering in the system. The saturation magnetization was enhanced by ions, reaching a maximum value of 23.864 emu/g. This enhancement makes the nickel-substituted zinc ferrite nanoparticles suitable for applications in data recording media and magnetic resonance imaging. Additionally, the values of the magnetic crystalline anisotropy constant, initial permeability, effective anisotropy constant, and anisotropic field of the synthesized samples were estimated.The optical properties of the synthesized samples were evaluated using UV-visible spectroscopy, and the band gap was determined through diffuse reflectance spectroscopy (DRS). The optical bandgap of pure zinc ferrite was measured to be 2.26 eV, and it decreased with increasing nickel concentration in the nanoparticles.

Structural, Magnetic and Electrochemical Properties of Nickel Manganese Ferrite (NixMn1-xFe2O4) Nanoparticles Prepared via Coprecipitation Method

In current work, the co-precipitation approach was effectively used to synthesize NixMn1-xFe2O4 nanoparticles. Thermal stability of the nickel manganese ferrite nanoparticle was observed at temperatures above 390 ºC by TG/DTA analysis. XRD investigation revealed the cubic structure of the synthesized NixMn1-xFe2O4 nanoparticles. The average crystallite size of synthesized nanoparticles determined via Scherrer’s equation, increases linearly with calcination temperature and nickel concentration. The FTIR spectra showed the existence of stretching vibrations of metal oxide, which are ascribed to the formation of nickel manganese ferrite nanoparticles. The surface morphology of NixMn1-xFe2O4 nanoparticles, as observed using FESEM, exhibited a spherical shape. The EDX spectrum indicates the occurrence of Ni, Fe, Mn and O in the synthesized nickel manganese ferrite nanoparticles. The average size of the crystallites, as determined by XRD, closely matches the analysis conducted using HRTEM. The magnetic properties of NixMn1-xFe2O4 nanoparticles were analyzed using VSM. Nickel manganese ferrite nanoparticles exhibit increasing saturation magnetization and coercivity values as nickel concentration increases, indicating soft ferrimagnetic properties and making it appropriate for high-density recording devices. The cyclic voltammetry investigation of Ni0.7Mn0.3Fe2O4 sample, calcinated at 600 ºC, reveals a significant specific capacitance of 590 F g–1 at a scan rate of 2 mV s–1, suggesting its potential use in supercapacitors.

PREDICTION OF STRENGTH DEPENDING ON THE INFLUENCE OF THE CHEMICAL COMPOSITION IN THE 40КХНМ ALLOY

Introduction. The study is devoted to the analysis of the influence of the chemical composition of the 40КХНМ alloy on its hardness. The relevance of the work lies in the fact that mechanical tests require significant material and time costs. For the operational assessment of metal quality criteria, it is proposed to apply mathematical modeling in the work. Materials and methods. A study of the effect of the chemical composition on the hardness of the 40KHNM alloy, which meets the requirements of the state standard 51397, was carried out. The results of the experiment. In the course of research, it was found that changes in the chemical composition of the 40КХНМ alloy significantly affect its mechanical properties, including hardness and resistance to shock loads. An increase in the content of carbon, molybdenum and chromium in the alloy leads to an increase in its hardness. This is with the formation of stronger carbide and molybdenum phases in the structure of the alloy, which leads to an improvement in its mechanical properties. Increased hardness makes the alloy more resistant to wear and increases its durability in operating conditions. An increase in the nickel content in the alloy leads to an increase in its resistance to shock loads. This is caused by an increase in plasticity and impact toughness of the alloy with an increased nickel content. Higher resistance to shock loads makes the alloy suitable for use in conditions that require high resistance to shocks, for example, in the production of machine parts and equipment. A mathematical model of the dependence of the strength of the alloy on the percentage content of the components of the chemical composition was built, which allows to control the indicators of the strength of the alloy in the process of its manufacture. Conclusions. The research results confirm that changes in the chemical composition of the 40КХНМ alloy have a significant impact on its mechanical properties. As a result of the experiments, it was established that the chemical composition of the metal significantly affects the hardness of the material. By changing the composition of the metal, it was possible to achieve a significant increase in hardness to levels that meet the requirements of quality standards. These results are an important step in optimizing the production processes and improving the properties of the final products from the 40КХНМ alloy.

The Effect of Nickel Content and Mechanical Activation on Combustion in the 5Ti + 3Si + <i>х</i>Ni System

Intermetallic alloys were synthesized in the 5Ti + 3Si + xNi system by the method of self-propagating high-temperature synthesis (SHS) and mechanosynthesis. The influence of nickel content on the morphology, size and yield of composite particles after mechanical activation (MA) of mixtures was studied. The dependences of the maximum temperatures and combustion rates, phase composition, morphology and elongation of synthesis products on the nickel content for the initial and MA mixtures are studied. Under the conditions of the experiments conducted in this work, combustion process was able to realize and at the same time the samples burned completely at a nickel content of 10 to 60 wt.% in the 5Ti + 3Si + xNi system. After MA, the samples from the 5Ti + 3Si mixture burned to the end, and during the activation of the 5Ti + 3Si + 40% Ni mixture, mechanochemical synthesis occurred. With increasing nickel content combustion temperature decreases, and combustion velocity behaves nonmonotonically, increases the size of composite particles and decreases the yield of the mixture after MA. MA practically did not affect the maximum combustion temperatures of mixtures of 5Ti + 3Si + xNi. A multiple (from 0.7 to 2.9 cm/s) increase in the burning rate of samples from MA mixtures with an increase in the Ni content from 20 to 30 wt. % was recorded. An increase in the nickel content leads to an increase in the content of triple phases and the amount of melt in the synthesis products of mixtures of 5Ti + 3Si + xNi. Shrinkage of product samples increases with increasing nickel content in the initial mixtures. After MA, the shrinkage of the product samples is replaced by their growth. Explanations of the observed dependencies are proposed.

Laser directed energy deposition of Alnico-8H from blended elemental powders: Effect of nickel increase on magnetic properties

Alnico-8H (14 wt% Ni) and Alnico-8H (19 wt% Ni) were additively fabricated from a blend of elemental powders with compositions (in wt.%) of 38Co-29Fe-14Ni-8Al-8Ti-3Cu and 33Co-29Fe-19Ni-8Al-8Ti-3Cu, respectively, using laser-directed energy deposition technique. Post additive fabrication both compositions were subjected to homogenization heat treatment at 1250 °C for 30 min and magnetic annealed at 650 °C under 2.5 T magnetic field for 60 mins (1 hr). X-ray diffraction was employed for studying the phase evolution. Scanning and transmission electron microscopes were utilized for characterization of Alnico alloys. The targeted compositions for Alnico-8H (14 wt% Ni) and Alnico-8H (19 wt% Ni) were nearly achieved in the L-DED processed samples. homogenization at 1250 °C, followed by magnetic annealing at 650 °C, resulted in an increase in grain size. The transmission electron microscopy revealed the presence of ferromagnetic α1 and paramagnetic α2 phases in the magnetic annealed microstructure. The increase in Nickel content from 14 to 19 wt% resulted in increase in coercivity (242 to 255 Oe), remanence (4437 to 8659 G), and maximum energy product (BHmax) (0.27 to 0.53 MGOe).

Role of site–specific doping in stabilizing high–nickel cathodes for high-performance lithium- ion -batteries

The growing demand for high-capacity and energy-dense lithium-ion batteries has driven the increase of nickel content in commercially available cathodes. However, during deep charging (delithiation), these Ni-rich cathodes experience a detrimental phase transformation and a sudden, significant decrease in lattice volume. This lattice collapse is considered the primary culprit behind the limitations in the cathode's electrochemical performance. Notably, the exact cause-and-effect relationship between the phase change and the collapse remains unclear. In the present study, the effect of the site of substitution on the performance of the LiNiO2 cathode has been investigated by adopting tungsten as a dopant. To gain deeper insights into this connection within Ni-rich LiNiO2, the contraction of the c-axis and the change in the a-axis during the delithiation have been investigated using ab initio density functional theory. Findings reveal that the free energy difference between the suspected phases in Ni-rich LiNiO2 is minimal at room temperature, facilitating the transition from the H2 to the H3 phase. This transition appears to be driven by the movement (gliding) of the NiO2 layer towards the adjacent Li layer. The findings of the present study indicate that among two different configurations due to different sites of substitution, the WLNO-2 configuration suppresses H2 –H3 phase conversion to a greater extent by hindering the gliding of the NiO2 layer toward the Li layer. Furthermore, a reduction in the collapse of the c-axis lattice during deep de-lithiation for the WLNO-2 configuration has been observed. This reduced collapse is primarily attributed to the altered charge distribution within oxygen atoms and the weakened screening effect from lithium ions.

DNA fragmentation of lymphocytes and sperm cells induced by nickel released from orthodontic archwires: A preliminary study.

Orthodontic brackets and archwires placed intraorally are subject to corrosion, leading to the release of cytotoxic metal ions. The aim of this study was to determine whether the use of orthodontic NiTi archwires increases systemic Ni levels and cause alterations on the DNA of cells unrelated to the oral environment such as lymphocytes and sperm cells. Human urine, semen and blood samples were collected before (baseline) sham placement of orthodontic archwires and 15 and 30 days after placement. Lymphocytes and sperm cells cells were evaluated by comet assay. Ni concentration levels in urine increased significantly between baseline and 15 days (p<0.01) and 15 and 30 days of exposure (p<0.01). Progressive decrease in sperm viability and motility was observed between the sampling periods. Lymphocytes and sperm cells showed DNA fragmentation. The increase in systemic concentration of nickel induced structural damage in the DNA of lymphocytes and human sperm cells.

Depletion of Electrolyte Salt Upon Calendaric Aging of Lithium-Ion Batteries and its Effect on Cell Performance

The trend for increased nickel content in layered transition metal oxide cathode active materials and increasing charging cut-off voltages aggravates aging of lithium-ion battery cells at high state of charge (SOC). We investigate the calendaric aging behavior of large-format automotive prototype cells and laboratory single-layer pouch cells at high but realistic cell voltages/SOCs and demonstrate that electrolyte oxidation in combination with follow-up reactions can cause a significant loss of the LiPF6 salt in the electrolyte. For this, we analyze the LiPF6 concentration in aged cells, the generation of H2 upon storage, and the cell resistance for different aging conditions. We show that the LiPF6 loss is a critical aging phenomenon, as it cannot readily be detected by capacity fading measurements at low/medium C-rates or by cell resistance measurements, while it severely reduces rate and fast-charging capability. Under certain circumstances, LiPF6 loss can even lead to a temporary capacity increase due to conversion of the conducting salt in the electrolyte to cyclable lithium in the active material. Finally, we suggest a possible reaction mechanism and a simple accounting model to keep track of how different side reactions involved in LiPF6 loss change the cyclable lithium inventory of a lithium-ion cell.

Looking into how nickel doping affects the structure, morphology, and optical properties of TiO2 nanofibers

In this paper, we have systematically studied the structural, morphological, and optical properties of Ni-doped TiO2, synthesized via a simple, cost-effective electrospinning method followed by calcination at 500 °C. The nanofibers with a core-shell structure were relatively homogeneous, smooth and randomly oriented, and there were no significant differences in fiber diameters due to Ni2+ content. Core loss mapping using electron energy loss spectroscopy confirmed an even distribution of titanium and relatively uniform nickel in the fibers. It was found that doping with 0.5 mol.% Ni2+ decreased the rutile content, while doping with 1 mol.% Ni2+resulted in a pure anatase phase with a significantly increased specific surface area (36.6 m2/g). Further increase in Ni2+ content (3–10 mol.%) not only prolonged the response of TiO2 nanofibers to visible light, but also increased the specific surface area (49.5 m2/g), decreased crystallite size (7 nm), and increased rutile content in TiO2 (33 wt.%). Photoluminescence analysis revealed that doping TiO2 with different amounts of Ni2+ leads to a gradual decrease of emission spectra intensity and red shift in the maxima positions. The XPS results confirmed that as the Ni2+ content enlarged, the Ti2+ and Ti3+ content increased significantly, effectively promoting the formation of oxygen vacancies. Raman analysis showed that an increase in nickel content (3–5 mol.%) led to a decrease and shift in peak intensity due to Ti3+ formation and also the possible presence of NiTiO3 phases. HRTEM analysis showed that Ni was doped into the substitution sites of both the anatase and rutile TiO2 lattice but had a stronger influence on the distortion of the anatase phase. The photocatalytic activity of Ni-doped TiO2 nanofibers was explored by analyzing the degradation of an antibiotic, oxytetracycline, monitored in laboratory conditions under visible light irradiation. After 60 min of irradiation, the degradation of OTC with 1Ni-TiO2 reached 76.4 % and with 10Ni-TiO2 70.5 %.

Magnetoelectric, dielectric, and magnetic investigations of multiferroic NixCo1−xFe2O4−SryBa1−yNb2O6 composites

Magnetoelectric (NixCo1−xFe2O4)0.3−(SryBa1−yNb2O6)0.7 composites with a 0–3 connectivity and different cation stoichiometries were synthesized via a classical mixed-oxide method. XRD patterns of all ceramics show reflections of the target phases SryBa1−yNb2O6 and NixCo1−xFe2O4. The influence of stoichiometry of the ferrimagnetic and ferroelectric phase on the magnetoelectric behavior was studied on composites with composition of (NixCo1−xFe2O4)0.3−(Sr0.5Ba0.5Nb2O6)0.7 and (NiFe2O4)0.3−(SryBa1−yNb2O6)0.7. The magnetic Curie temperature increases with nickel content. However, the saturation magnetizations as well as the Curie temperatures of the composites are always lower than the ones of bulk NixCo1−xFe2O4 samples. The maximum magnetoelectric coefficient (αME) rises with increasing nickel content from 40 (x = 0) to 180 µV Oe−1 cm−1 (x = 1) in accordance with the dynamic magnetostriction coefficient. The evolution of αME of (NiFe2O4)0.3−(SryBa1−yNb2O6)0.7 composites shows an increase with strontium content up to y 0.5. Higher strontium content leads to a significant reducing of αME.

Functional Improvement of NiOx/CeO2 Model Catalyst Active in Dry Methane Reforming via Optimization of Nickel Content

The valorization of greenhouse gases, especially when focused on carbon dioxide, currently belongs to the main challenges of pro-environmental chemical processes. One of the important technologies in this field is dry methane reforming (DMR), leading to the so-called synthesis gas (CO + H2). However, to be efficient and economically viable, an active and stable catalyst is required. Ni-based systems can be recommended in this regard. This research aimed to investigate how nickel content can influence the activity of model NiOx/CeO2 catalysts in DMR. A series of NiOx/CeO2 samples of various nickel loadings (0–10 wt.%) were prepared through dry impregnation. The obtained samples were characterized through XRD, RS, N2-BET, DRIFT, SEM, UV/Vis-DR, and XPS. Nonlinear changes in surface properties of the investigated samples with increasing nickel concentration were found. The observed changes are mirrored both in the determined nickel speciation and in the corresponding catalytic activity. The highest activity was found for the catalyst containing 3 wt.%. of nickel.

Densification Behaviours of TiC/Ni Metal Ceramic Alloys Produced by Powder Metallurgy

Ceramic Metallic Alloys of TiC/Ni, Comprising Titanium Carbide with Nickel Contents of 5%, 15%, 30%, and 50%, were Fabricated through Solid-Phase Sintering at 1400°C with a 2-hour Holding Time and a Pressure of 50MPa. This Study Explores the Impact of Nickel Content on the Mechanical and Structural Properties. The Solidification Mechanism between TiC and Ni is Governed by Carbon Diffusion through TiC Particles, Affecting the Morphology of TiC and Carbon Particles in Ni Samples. The Reaction Behavior within the TiC/Ni Alloys was Analyzed, and Microstructural and Mechanical Characteristics were Examined to Evaluate the Influence of Varying Nickel Contents. Results indicate that in all samples, the TiC matrix exhibited a solid solution of the FCC phase. The reaction mechanism of Ti-C-Ni reveals the evolution of solid phase formation with increasing nickel content. As nickel content increases, the mass and size of nickel particles grow, leading to a more uniform and homogeneous structure. At a nickel content of 15%, the samples displayed a bending strength of 1200 ± 50 N, a microhardness of 800 ± 20 (HV 0.1), and a density of 5.6 ± 0.2.

ICEMS Characterization of NixFe3-xO4 (0.7 ≤ x ≤ 1.7) thin films grown by ion beam sputtering on (0001) Al2O3 substrates

We report here on the ICEMS characterization of nickel ferrite (NixFe3−xO4) thin films having different nickel contents grown on alumina substrates by Ion Beam Sputtering. The spectra corresponding to the films with nominal x = 0.7, 1.0 and 1.2 are characteristic of compounds crystallizing in a spinel-related structure showing two different magnetic sextets associated with Fe3+ located in the tetrahedral and octahedral sites of such structure. The spectra show an additional broad third sextet with a large isomer shift which suggests the occurrence of electron hopping between Fe2+ and Fe3+ ions sitting in the octahedral sites. With increasing nickel content, the linewidth of the sextets increases and their corresponding hyperfine magnetic fields decrease. This is an indication of an increase in structural disorder in the deposited films as their nickel concentrations increase. The cation distribution of the iron ions over the tetrahedral and octahedral sites appears also to depend on the nickel content. The film with x = 1.2 shows a significant increase in the fraction of octahedral iron ions as compared with the expected nominal value suggesting that, for this composition, some Ni2+ could also occupy tetrahedral sites. The Mössbauer spectrum corresponding to the film with x = 1.7 shows a magnetic pattern with very broad lines similar to those shown by amorphous or disordered materials. The average isomer shift is quite high (around 0.40 mms− 1) and characteristic of Fe3+ in octahedral oxygen coordination. This indicates that for the largest nickel content studied (x = 1.7), the film does not contain Fe3+ in tetrahedral environments suggesting that the spinel structure is no longer present. This correlates well with the X-Ray Diffraction data which indicate a structural change from spinel to a disordered rock-salt structure for this particular film with high nickel content.

Detachment and flow behaviour of anode slimes in high nickel copper electrorefining

Most of the world’s copper is produced via copper electrorefining, where nickel is the most abundant impurity in the process. Previously it has been suggested that nickel affects the adhesion of anode slimes on the anode as well as the porosity of the slime layer that forms. This paper investigates the effects of nickel, oxygen, sulphuric acid and temperature on the detachment of anode slimes from the anode surface. The detachment of particles as a function of both anode and electrolyte composition was studied on laboratory scale using a camera connected to a Raspberry Pi, and particle detection and movement analysed using TrackPy. The results revealed four different slime detachment mechanisms: cloud formation, individual particle detachment, cluster detachment and avalanche. These were found to be dependent on the electrolyte (0, 10, 20, 30 g/dm3 Ni2+ &amp; 100, 200 g/dm3 H2SO4), with increasing nickel concentration promoting cluster detachment and increasing sulphuric acid concentration favouring detachment of individual particles. Anode composition (0.05-0.44 wt% O and 0.07-0.64 wt% Ni) was shown to affect the flow direction of anode slimes, with increasing nickel leading to more upward-flowing slimes. Typical particle movement velocities were from -0.5 to 1.0 mm/s regardless of the electrolyte and anode composition, and regardless of the operating temperature (25 °C &amp; 60 °C) for small particles (&lt;0.5 mm). The results also support previous findings that increasing the nickel concentration of the electrolyte leads to a more porous anode slime layer on the anode.

Influence of nickel addition on the microstructure, mechanical, and wear properties of Zn‐40Al‐2Cu alloy

AbstractTo study the influence of nickel addition on the microstructure, mechanical and lubricated wear properties of Zn‐40Al‐2Cu alloy, one ternary and five quaternary Zn‐40Al‐2Cu‐(0.5‐2.5)Ni alloys were made by permanent mold casting. The wear behavior of these alloys was studied using a block‐on‐cylinder type test machine, after examining their microstructural and mechanical features. The microstructure of Zn‐40Al‐2Cu alloy was comprised of aluminum‐rich α dendrites and a eutectoid α+η phase mixture. The addition of nickel caused the formation of intermetallic Al3Ni particles in the microstructure of this alloy. As the nickel content of alloys increased their hardness, friction coefficient, working temperature, and average surface roughness increased to certain extents but their strength, ductility, impact resistance, and wear volume decreased. However, the values of their wear volume and average surface roughness exhibited opposite changes with increasing nickel content. The worn surfaces of Zn‐40Al‐2Cu‐Ni alloys were observed to be characterized by smearing and scratching marks. Furthermore, the wear and mechanical properties of these alloys were correlated, and the results were discussed in terms of their microstructural features. Finally, it may be concluded that the nickel addition adversely affects the ductility of Zn‐40Al‐2Cu alloy but increases its wear resistance.

Investigation of Optical and Dielectric Properties of Nickel-Doped Zinc Oxide Nanostructures Prepared via Coprecipitation Method

Nanostructures of undoped zinc oxide and nickel-doped zinc oxide (Ni = Zn0.98Ni0.02O, Zn0.96Ni0.04O, and Zn0.94Ni0.06O) were synthesized by using the coprecipitation process, and their optical and dielectric properties were simultaneously investigated. The XRD results confirm the hexagonal structure having space group P63mc. By increasing nickel concentration, the particle size decreases, while the strain is increased. Fourier-transform infrared (FTIR) analysis was carried out in order to learn more about the phonon modes present in nickel-doped zinc oxide. UV-Vis spectroscopy further revealed that the optical band gap of nickel-doped samples varied from 3.18 eV to 2.80 eV. The SEM analysis confirms the rod shape morphology of the already synthesized samples. EDX analysis investigates the incorporation of nickel ions into the zinc oxide lattice. Using photoluminescence spectroscopy, we found that the synthesized materials had oxygen vacancies (Vo) and zinc interstitial (Zni) defects. Dielectric constant (εr) and dielectric loss (ε) are both improved in nickel-doped zinc oxide compared to undoped zinc oxide. Since more charge carriers enhanced after the nickel ions were exchanged for the Zn ions, the AC electrical conductivity (σa.c) improves by nickel doping compared to undoped zinc oxide.

Smart-responsive sustained-release capsule design enables superior air storage stability and reinforced electrochemical performance of cobalt-free nickel-rich layered cathodes for lithium-ion batteries

Nickel-rich layered oxide stands as one of the most promising cathodes in demand for higher energy density of lithium-ion batteries (LIBs) in next generation. While increasing nickel content brings more capacity, it also makes this kind of cathode more vulnerable to the ambient, both the air outside the cell and the electrolyte inside, causing aggravated storage, structural and thermal instability. The cathode surface, as the first line of defense against the ambient attack, is the essential place to address these issues. Enlightened by the mechanism of “sustained-release capsule”, here we decorate the polydimethylsiloxane (PDMS), a skin with exceptional moisture-resistance and chemical stability, onto the surface of LiNi0.9Mn0.1O2. This PDMS skin demonstrated the smart response to the surrounding environment that the hydrophobic surface guarantees the ambient air storage stability by cutting off residual alkali accumulation and the protective role of coating could be relayed as another functional mechanism once entering the battery. The detrimental HF species generated from water-induced electrolyte decomposition are effectively captured and eliminated to defend cathode corrosion and enhance interfacial stability during long-term cycling. Attributed to the seamless protection from the outside to the inside of the battery, this well-capsuled Ni-rich cathode exhibits negligible capacity fading compared with fresh state even after long ambient exposure, and realizes superior cycling and thermal stability. This work demonstrates new guidelines to design smart-responsive coatings for cathode materials to reduce their susceptibility to the surrounding environment, towards improving both ambient storage stability and cycling stability.