Increasing Nickel Content Research Articles

Influence of Nickel in water on properties of Ordinary Portland Cement Concrete

The study is aimed at investigating the effect of presence of Nickel in water on setting times and compressive strength of cement concrete. In the present study, the effect of Nickel (Ni) on setting time and compressive strength of cement is assessed under laboratory conditions. The research programme included tests of setting times and Mechanical strengths up to 28 days. In this research, the cement concrete cubes were cast with deionised water and deionised water containing the Nickel ions at various concentrations. The concentrations of Nickel (Ni) tested for different samples are 10, 50, 100, 500, 1000, 2000, 3000, 4000 and 5000 mg/L. The experimental results show that the presence of Nickel in deionised water accelerate both initial and final setting times up to 2000 mg/L. Nickel in deionised water up to 2000 mg/L there is a nominal change in compressive strength at early age (3-day). Beyond 2000 mg/L there is a significant change in the compressive strength at early ages as well as 28-day. Comparison of the Nickel with those of control mix levels reveal that the presence of Nickel increases the compressive strength. The rate of increase in compressive strength is with increase in concentration of Nickel.

Elucidating local diffusion dynamics in nickel-rich layered oxide cathodes.

Elucidating Li-ion transport properties is essential for designing suitable methodologies to optimise electrochemical performance in Ni-rich cathodes for high energy density Li-ion batteries. Here, we report the local-scale Li-diffusion characteristics of a series of nickel-rich layered oxide cathodes, prepared via microwave methods, using muon spin relaxation methods. Our results detail the effects of cation dopants, selected for structure stability, on transport properties in candidate nickel-rich chemistries. We find that the local diffusion properties improve with increasing nickel content. Our results demonstrate that these observations are dependant on substitutional effects.

Merenje kvaliteta vazduha u aglomeraciji Bor u 2022. godini u periodu rekonstrukcije topionice bakra u Boru

This paper presents the results of the air quality measurements in the agglomeration of Bor in the period June-December 2022, in which the Copper Smelter in Bor was not working due to the works on reconstruction and increasing the capacity for copper concentrate processing. Based on an analysis of the existing measuring points and concentrations of pollutants, measured in the local and national air quality monitoring network in the territory of the Bor agglomeration, as well as the possible impact of the new mining and metallurgical facilities in the company Serbia ZiJin Copper Bor, the additional locations, where the measurements were performed, were selected. The air quality measurement results show that there was no exceedance of the hourly and daily limit values for gaseous pollutants, nor were there an exceedance of the limit value for the mean daily concentration of lead in the suspended particles of the PM10 fraction, as well as the target values for the concentrations of cadmium and nickel in PM10. The arsenic concentration in PM10 at the measuring point of PU Bor was above the target annual value for 3 days. The maximum measured mean daily value of arsenic concentration in PM10 at this measuring point was 11.3 ng/m3 . Based on a complete insight into the results of air quality measurements in the Bor agglomeration in 2022, it can be concluded that the dominant share of concentration of SO2 , CO, as well as the concentration of arsenic, cadmium, and lead in PM10, originates from the gaseous pollutant emissions from the Copper Smelter Bor in the period when it operates. It was established that at the measuring point MMI Bor, the nitrogen oxide emissions from traffic mostly affect the level of nitrogen oxides in the air. Also, the measurement results indicate that the operation of the Smelter in 2022 did not significantly contribute to the concentration increase of suspended PM10 particles in the agglomeration of Bor, and that during the period of operation of the Copper Smelter in 2022, no copper concentrates with increased nickel content were processed.

Assessment of impact of nickel stress on the accumulation, pigments and protein content of water hyacinth (Pontederia crassipes L.)

Pontederia crassipes L. plants were collected and exposed to different concentrations (Control, 0.01, 0.1, 1.0 and 10.0 ppm) of Ni by using NiSO4 in medium in the laboratory. The effect of Ni2+ concentrations on visible symptoms such as toxicity, pigments (Chlorophyll- a, b and total) contents were estimated. Plants exposed to high nickel (1.0 and 10.0 ppm) showed visible toxicity symptoms such as wilting, chlorosis in young leaves, browning of roots noticed after 6 days of treatment. Nickel was accumulated more in stem (651.1µg/g dry weight) than leaves (115.23 µg/g dry weight) at 6 days of treatment. Nickel exposure decreased Chlorophyll-a, b and total chlorophyll contents. Body water content decreased at high nickel (1.0 and 10.0 ppm). Increased nickel concentrations increases antioxidants such as proline content. On the other hand carotenoids and protein contents at 1.0 ppm of nickel were decreased. The low level of nickel stimulates photosynthetic pigments and antioxidative parameters.

Synthesis, properties and applications of novel inorganic yellow pigments based on Ni-doped Al2TiO5

Single phase Al2-2xNixTi1+xO5 (0 ≤ x ≤ 0.4) solid solutions were successfully synthesized by solid-phase reaction. The color of the compounds varied from yellow (x = 0.1) to turmeric (x = 0.4) with increasing nickel content. X-ray photoelectron spectroscopy analysis confirmed that the oxidation state of Ni is +2. The UV–Vis absorption spectrum showed that the color of the sample comes from the d-d transition of Ni2+ in octahedral coordination. Owing to excellent high temperature stability, the as-prepared oxide powders (10 wt%) were mechanically mixing with Al2O3 by conventional ball milling to prepare colored alumina ceramics. When Al2O3 is in excess, the blue NiAl2O4 impurity phase appeared, contributing to an intense green color of the Al2O3 ceramics composite. The Vickers micro hardness value of green alumina was higher than that of pure white alumina. The as-prepared samples were also dispersed in PMMA and bright yellow polymer composites were obtained, indicating great potential in polymer colorant.

THE IMPACT OF AGROTECHNICAL FACTORS ON THE CONTENTS OF CHROMIUM AND NICKEL IN GRITS OF SELECTED VARIETIES OF SPRING BARLEY

Fertilization and soil tillage have an important position in agriculture, because the modification and availability of nutrients from the soil to plants, as well as heavy metals are related to these mentioned treatments. The main negative impact of heavy metals on the environment is their non-degradability. In our study, the samples of barley grits were analysed, where chromium and nickel contents were determined depending on different agrotechnical methods of growing cereal plants. The field trials were based on a plot of land in the cadastral territory of Dolná Malanta near the city of Nitra in the Slovak Republic. The plot area was 14 m2. In the experiment, three different dosages of macroelements into the soil were applied, and two methods of soil treatment by ploughing were also performed. Barley grits were obtained by grinding of grains of four varieties of spring barley: KM2084, Lédi, Xanadu and Marthe. The lowest content of chromium and nickel in barley grits was determined in the KM2084 variety. The amounts of chromium in the barley grits of our tested samples were in the range 0.17-0.77 mg.kg-1 dry matter and nickel 0.05-0.76 mg.kg-1 dry matter, respectively. According to the Food Code of the Slovak Republic, the maximum permissible amount of chromium (0.77 mg.kg-1) was exceeded, mainly in the Lédi variety, in the case of nickel, its exceeding of the maximum permissible amounts (0,76 mg.kg-1) was not determined in any variety. NPK fertilization in the ratio 16:1:4 (70 kg N ha-1) in combination with minimization ploughing, as well as fertilization in the ratio 2.5:1:1.5 (60 kg N ha-1) in combination with conventional ploughing had an effect on an increase in chromium contents in barley grain in all varieties, but at the same time caused a decrease in nickel contents, except for the Xanadu variety. The same values were determined in the fertilized variant with the addition of limestone after the application of conventional ploughing. The application of conventional ploughing on unfertilized areas had an effect on the increase of nickel contents in all varieties and the decrease of chromium contents in three varieties of spring barley.

Highly porous FeNi 3D foams produced by one-step electrodeposition: Electrochemical stability and mechanical properties

Highly porous iron‑nickel foams, including the first-ever reported pure iron foam, were prepared by the dynamic hydrogen bubble template electrodeposition method and studied regarding their electrochemical stability and mechanical properties. Changes on the morphology, microstructure, and electrochemical resistance of the foams were investigated as a function of the Fe:Ni ratio by scanning electron microscopy (SEM), d.c. polarization and electrochemical impedance spectroscopy (EIS). Tensile and bending tests were carried out to evaluate the mechanical behavior of the prepared foams. Both crystalline structure and morphology are affected by the increase of Ni content, evolving from a highly porous foam with a body-centered cubic (bcc) structure to a denser material with open pores and face-centered cubic (fcc) structure. Polarization curves reveal an ennoblement of the corrosion potential as the nickel content increases. The impedance response revealed a dependence on the foam porosity. An increased number of pores was found more detrimental to the mechanical properties of the foams, as fractures seem to propagate, preferentially by cracks due to connecting pores. As result, foams with higher Ni contents displayed better mechanical performance for both tensile and bending assays. Results show that this innovative and powerfull technique enables to design iron foams with the adequate properties required for industrial applications. • Fe and FeNi nanofoams are prepared by Dynamic Hydrogen Bubble Template Electrodeposition. • Pure iron foam is obtained for the first time. • Foams morphology change for higher Ni contents. • Faradaic resistance depends on both %Fe and the pore availability. • Improved mechanical resistance is observed for the less porous foams.

A facile pyrolysis synthesis of Ni doped Ce2O3@CeO2/CN composites for adsorption removal of Congo red: Activation of carbon nitride structure

Sheet-like Ni doped Ce2O3@CeO2/CN composite is synthesized by tuning the introduction of nickel in a facile and low-cost pyrolysis process. Due to the activation of the shell-core Ce2O3@CeO2 structure, the nitrogen chemical state in the carbon nitrides is mainly in the form of an N-(C3) structure, inducing the production of excellent electronic conductivity and positive charges on carbon nitrides. For the pyrolytic synthesis of the composite, the amount of nickel doping is a crucial factor. Under no nickel condition, only CeO2 is synthesized and positively charged. With increasing nickel content, Ni doped CeO2/CN composite is prepared and negatively charged due to its main component of CeO2 and the change of its carbon nitride structure. Ni doped CeO2 prepared with high enough nickel content presents individual NiO particles and its negatively charged surface. The removal of these designed composites for anionic Congo red is utilized to reveal the significant influence of their surface structure. Ni doped Ce2O3@CeO2/CN composite depicts the highest removal performance. Ni doped CeO2/CN composite, despite the great change in its carbon nitride structure, still has much higher removal efficiency than pure CeO2. However, Ni doped CeO2 is found to have lower adsorption performance than pure CeO2.

Effect of Ni Substitution on the Structural, Magnetic, and Electronic Structure Properties of Gd0.4Tb0.6(Co1-xNix)2 Compounds.

The comprehensive research of magnetic and electronic structure properties of the new class of Gd0.4Tb0.6(Co1-xNix)2 compounds, crystallizing in the cubic Laves phase (C15), is reported. The magnetic study was completed with electrical resistivity and electronic structure investigations. The analysis of Arrott plots supplemented by a study of temperature dependency of Landau coefficients revealed that all compounds undergo a magnetic phase transition of the second type. Based on magnetic isotherms, magnetic entropy change (ΔSM) was determined for many values of the magnetic field change (μ0H), which varied from 0.1 to 7 T. For each compound, the ΔSM had a maximum around the Curie temperature. Both values of the |ΔSMmax| and relative cooling power RCP parameters increased with increasing nickel content. It is shown that structural disorder upon Co/Ni substitution influences some magnetic parameters. The magnetic moment values of Co atoms determined from different methods are quantitatively consistent. From the M(T) dependency, the exchange integrals JRR, JRT, and JTT between rare-earths (R) and transition metal (T) moments were evaluated within the mean-field theory (MFT) approach. The experimental study of the electronic structure performed with the use of the X-ray photoelectron spectroscopy (XPS) was completed by calculations using the full-potential linearized augmented plane waves (FP-LAPW) method based on the density functional theory (DFT). The calculations explained experimentally observed changes in the XPS valence band spectra upon the Ni/Co substitution.

Synthesis of a magnetically removable visible-light photocatalyst based on nickel-doped zinc ferrite

In this study, a facile method to synthesize magnetically removable visible-light photocatalysts based on nickel-doped zinc ferrites is presented. Ferrite semiconductor ceramics with the general formula Zn1-xNixFe2O4 (0 ≤ x ≤ 0.5, Δx = 0.1) were prepared by high-energy ball milling followed by annealing at 873 K. X-ray diffraction analysis confirmed the spinel single-phase Fd-3m without secondary phases for all compositions. The slight decrease in lattice parameters confirmed the presence of Ni2+ ions in the crystal structure because Ni had a smaller ionic radius than Zn. Raman spectroscopy demonstrated that Ni2+ ions were distributed on both tetrahedral and octahedral sites, which increased the inversion parameter and affected the photocatalytic efficiency and ferromagnetism. Magnetic hysteresis loops suggested an increase in the specific magnetization as the doping content increased, enabling magnetic recovery and reuse of the photocatalyst in water remediation. Diffuse reflectance spectroscopy showed a reduction in the band gap values with increasing nickel content, which was attributed to forming a sub-level in the band structure in the presence of Ni2+. Photocatalytic tests revealed a degradation efficiency higher than 60%, confirming that the doped samples obtained by high-energy ball milling were highly efficient and easily removable photocatalytic materials.

Characterization of Low Cobalt Cathode Degradation Using Distribution of Relaxation Times Analysis

High-capacity cathode materials with reduced or eliminated cobalt usage are being pursued for lithium-ion batteries (LIB) due to environmental and humanitarian issues in the cobalt supply chain. Consequently, increased nickel content and reduced cobalt content results in faster cell degradation. A connection between morphological and chemical changes within the cathode microstructure, charge cut-off voltage, and operating temperature has been developed through a combination of cycling conditions, X-ray Diffraction (XRD), and Distribution of Relaxation Times (DRT) analysis.Low cobalt half-cell batteries were fabricated with Li(Ni0.8Mn0.1Co0.1)O2 (NMC811) active material and tested under high cut-off voltage (4.3V), low cut-off voltage (4.0V), high temperature (60°C), and ambient temperature (25°C). XRD analysis of high cut-off voltage samples show a presence of NiOx crystalline structure, a low diffusivity rock-salt phase. To further understand the electrochemical changes due to the appearance of the rock-salt phase, DRT analysis was conducted on the electrochemical impedance spectra taken after formation of the solid electrolyte interphase (SEI) and after cycling. DRT analysis is becoming a preferred method of analysis due to the fact that electrochemical processes, like solid-state diffusion, cathode electrolyte interphase (CEI), and SEI formation, show up at characteristic frequencies, allowing for interpretation of changes that are often not visible within typical impedance plots. Prior to cycling, the primary contribution was initially found to be from the CEI and SEI. At low cut-off voltage cycling conditions, ambient temperature cycling showed that the contribution shifted from the CEI to diffusion resistance, but changes within the SEI and CEI were still detected. High temperature cycling conditions within the low cut-off voltage samples showed that the diffusion resistance again increased and the contributions from the CEI and SEI decreased. At high cut-off voltage cycling conditions, ambient temperature cycling showed that diffusion was becoming the main contribution but changes due to the CEI were still evident. High temperature cycling conditions in the high cut-off voltage samples showed that the mechanism was completely taken over by diffusion, due to the lithium transport being limited by the rock-salt phase or electrolyte degradation.XRD patterns confirmed that the rock-salt phase was beginning to form within the low cut-off voltage high temperature cycling condition, but in much lower intensity than that of the high cut-off voltage condition. This observation clearly shows that the diffusion mechanism, which hinders intercalation and deintercalation, is driven by the formation of the non-conductive rock-salt phase. While primarily influenced by cut-off voltage, elevated temperature may also contribute to this degradation mechanism. The combination of different electrochemical and microstructural characterization techniques supports this observation and demonstrate that DRT analysis is an effective method to better understand the driving mechanisms behind battery degradation.

Features of microstructure, phase composition and strengthening capability of stainless steels with 13 – 17 % Cr

The paper considers the study of the features of structure and phase transformations in high-strength, resistant to carbon dioxide corrosion, complex alloyed steels of martensitic, austenitic-martensitic and martensitic-ferritic classes with 13 – 17 % Cr. Influence of the alloying on crystallization and solid state phase transformations was revealed in the temperature range of hot deformation and heat treatment using thermodynamic modeling and experimental study. The effect of quenching temperature on the phase composition and microstructure was analyzed as a result of X-ray diffraction phase analysis, optical and transmission electron microscopy. It was found that increase of nickel content leads to growth of retained austenite fraction resulting in significant decrease of yield strength along with high tensile strength and elongation. To obtain predominantly martensitic microstructure in martensitic-austenitic steel, the multistage heat treatment is proposed including quenching, intermediate annealing for precipitation of dispersed carbides and tempering forming final mechanical properties. The composition of precipitated carbides was evaluated by X-ray microanalysis. The results of the tensile test for steels with martensitic and martensitic-ferritic microstructure showed that required strength grade (σ0.65 ≥ 862 MPa; σв ≥ 931 MPa) was reached after heat treatment including quenching and tempering. Multistage heat treatment including quenching, intermediate annealing and final tempering was resulted in required strength properties of high-nickel martensitic-austenitic steel with 15 % Cr.

Sol/Antisolvent Coating for High Initial Coulombic Efficiency and Ultra-stable Mechanical Integrity of Ni-Rich Cathode Materials.

The Ni-rich cathode holds great promise for high energy density lithium-ion batteries because of its high capacity and operating voltage. However, crucial problems such as cation disorder, structural degradation, side reactions, and microcracks become serious with increasing nickel content. Herein, a novel and facile sol/antisolvent coating modification of Ni-rich layered oxide LiNi0.85Co0.1Mn0.05O2 (NCM) is developed where we use ethanol to disperse the nanosized LiBO2 to form the sol and adopt tetrahydrofuran (THF) as antisolvent to prepare the cluster of nanoparticles to be coated on the surface of NCM. The coating thickness can be tuned through the THF addition amount. The LiBO2 nanorod deposition is formed as well over the crack of the NCM cathode, likely acting as a patch to repair the original defect of the intrinsic crack. The uniform LiBO2 nanospherical particle coating together with LiBO2 nanorod wrapping provides a double protection against electrolytes. Compared with the raw material, LiBO2-coated LiNi0.85Co0.1Mn0.05O2 (LiBO2-coated NCM) exhibits a high initial Coulombic efficiency of 90.3% at 0.2 C between 2.8 and 4.3 V vs Li+/Li, a superior rate capability, enhanced fast charge property at 3 C, and restricted microcrack formation. This simple in-site modification and repairing technology guarantees a good mechanical integrity of the polycrystalline Ni-rich cathode.

Material properties of gradient copper‐nickel alloy fabricated by wire arc additive manufacturing based on bypass-current PAW

In this paper, the bypass-current plasma arc welding (BC-PAW) based on PAW was employed to fabricate copper-nickel (Cu-Ni) gradient thin-walled structures. The effect of forming accuracy and compositional homogeneity of the bypass current Cu-Ni structure was first verified by controlled experiments. The effect of Ni content on the microstructure and mechanical properties of Cu-Ni gradient structures fabricated using bypass current was then investigated, with a focus on grain orientation and texture analysis of the three intermediate Cu-Ni mixed gradient layers. The results showed that the use of bypass current in the additive manufacturing of Cu-Ni gradient structures can improve the forming accuracy and effectively eliminate lateral composition deviations within the gradient layers. In the Cu-Ni mixed gradient layers, the average grain size of the gradient layers decreased with increasing nickel content, and unusually large secondary grains appeared in different gradient layers. Due to the different Ni content, different degrees of amplitude modulation decomposition occurred in different gradient layers, resulting in changes of grain orientation and texture composition. Under the combined effects of solid solution strengthening, fine grain strengthening and amplitude modulation decomposition, the microhardness and tensile strength increased with increasing nickel content and then decreased, reaching a maximum near the side of the gradient composition biased toward nickel. The fracture analysis showed a transition from ductility to quasi-fracture.

Impact of Ni on the thermophysical and thermodynamic properties of Fe–C–Ni based alloys

Three model alloys based on Fe-C-Ni were studied containing carbon between 0.338 and 0.382 wt. % and nickel between 1.084 and 4.478 wt. %. Phase transition temperatures, heat capacity, enthalpy change, heat of fusion, coefficient of thermal expansion, and density were experimentally and theoretically determined in the high-temperature area from 1000 °C to 1595 °C. A number of techniques, namely differential thermal analysis (DTA), differential scanning calorimetry (DSC), and dilatometry, were used in this study, and the heat of fusion was determined by two approaches, that is, from the DSC peak area and from the enthalpy change. The experimental data were compared and discussed with the calculation results obtained using SW IDS, JMatPro, and Thermo-Calc operating with the commercially available TCFE8 thermodynamic database. The obtained experimental results show that the liquidus temperature and the coefficient of thermal expansion decrease with increasing nickel content. On the contrary, the density and heat of fusion values derived from the DSC peak increase with increasing nickel content. Furthermore, an ambiguous influence of nickel on the change in solidus temperature, heat capacity, enthalpy change, and heat of fusion obtained from the enthalpy change was observed.

Contrasting tolerance and gene expression between white pine (Pinus strobus) and jack pine (P. banksiana) exposed to an increasing nickel concentration

Studies on copying mechanisms of Pinus strobus and P. banksiana to soil metal contamination are limited. The objectives of this study were to 1) determine if P. strobus or P. banksiana are Ni resistant 2) If Ni associated genes will show differential expression under increasing concentration of Ni; and 3) if Ni mobility and accumulation in these two species show different patterns. We determined how these two species respond to soil nickel contamination. Damage ratings revealed that P. banksiana is susceptible to high concentration of Ni(NO 3 ) 2 (1600 and 3200 mg/kg) while P. strobus was tolerant. Soil nickel treatments induced a downregulation of high affinity- Ni transporter family AT2G16800 and Natural resistance-associated macrophage proteins ( NRAMP3 ) in both species with the severity increasing at high levels of Ni. A concentration-dependent response of 1-aminocyclopropane-1-carboxylic acid deaminase ( ACC deaminase ) in both species consistent with the hormetic effects was observed. Nickel triggered also a concentration-dependent downregulation of serine acetyltransferase ( SAT ) in P. strobus with the lowest concentration showing the highest repression. An opposite trend was observed in P. banksiana where Ni induced an upregulation of SAT . Interestingly, the mobility of Ni in the two pine tissues showed a similar pattern. Analysis of response of P. strobus and P. banksiana to nickel in metal contaminated lands showed an uptake of Ni from the rhizospheres and its bioaccumulation in roots. The Ni translocation from roots to branches or needles showed limited to moderate mobility of Ni ions to aerial parts with no significant accumulation in those tissues.

Electrochemical Characterization and Microstructure Evolution of Ni-Rich Layered Cathode Materials by Niobium Coating/Substitution

The high nickel layered mixed metal oxides, such as LiNizCoyMn1–z-y–qAlqO2, are the most utilized cathode materials in Li-ion batteries for electric vehicles due to their high energy density. However, as the nickel content increases, they suffer from poor capacity retention and from voltage fading due to interfacial/structural instability. In this paper, a series of Nb-coated/substituted LiNi0.9Co0.05Mn0.05O2 (NMC 9055) were synthesized by reacting the Nb precursors, Ni0.9Co0.05Mn0.05(OH)2, and LiOH. Nb is found in the NMC structure and also on the grain boundaries between the primary particles. These Nb-modified materials showed improved capacity retention and charge/discharge voltage profiles over the untreated material; the capacity retention was 86.4% (0.7 Nb-NMC 9055) vs 93.5% (1.4 Nb-NMC 9055) vs 99.7% (2.1 Nb-NMC 9055) vs 75.3% (NMC 9055) after 200 cycles and nearly no voltage fading (1.4 Nb-NMC 9055 and 2.1 Nb-NMC 9055) during cycling. High-angle annular dark-field (HAADF) scanning transition electron microscopy (STEM) images showed that the added niobium (Li–Nb–O phase) is located in the boundaries between the primary particles. This transferred obvious interparticles/intraparticles cracking into tiny intraparticles cracking, which benefits the release of strain/stress, maintains the mechanical integrity of secondary particles, and inhibits the structural transformation from the layer structure to rock-salt phase supported by large reduced charge transfer resistance, thus enhancing the electrochemical performance of NMC 9055.

Hydrogen storage characteristics, kinetics and thermodynamics of Gd-Mg-Ni-based alloys

Gd5Mg95-xNix (x = 5,10,15) alloys were melted in a vacuum induction furnace, and the phase composition, microstructure and storage properties of gaseous hydrogen were investigated using scanning electron microscopy (SEM) and X-ray diffractometry (XRD). Hydrogen storage performance includes hydrogen absorption/desorption capacity, particle powder and platform pressure. The activation energy, entropy and enthalpy of the dehydrogenation reaction were calculated. The results show that GdMg5, Mg2Ni are the main phase and the secondary phase of the alloys respectively. After hydrogen absorption, the main phase transformation is MgH2, and the secondary phases are Mg2NiH4 and GdH3. After dehydrogenation, the main phase transformation is Mg, and the secondary phases are Mg2Ni and GdH2. GdH3 has poor thermal stability and can be easily decomposed into GdH2. Hydrogen storage capacity gradually decreases as the nickel content increases, but the kinetic performance is significantly improved. The change in nickel content has no significant effect on the thermodynamic.

Recent progress on the modification of high nickel content NCM: Coating, doping, and single crystallization

AbstractHigh nickel content layered cathodes, represented by NCM (LiNixCoyMnzO2, x + y + z = 1), are now widely employed in the market of electric vehicles, owing to their high energy density. With the gradual increase of nickel content and capacity, the issues on cycling life and safety become more serious. In this review, various strategies for improving the performance of high nickel NCM are summarized on the aspects of surface coating, ionic doping, and single‐crystal NCM. The coating strategy was separately described according to the physical property of coating species, including inert material coating, Li+‐conductor coating, electronic conductor coating, and mixed conductor coating. These coating species help to suppress the interfacial oxidation of electrolytes by NCM, improving the cycling life and safety. The elemental doping in the crystal lattice of NCM is then presented in the aspects of cation, anion, and mixed‐ion doping, which are beneficial to stabilize the layered structure during charge–discharge and so promote the electrochemical performance. In quite recent years, the strategy of single‐crystal NCM was demonstrated to be a promising pathway, owing to the dramatically reduced surface area and grain boundary. Finally, the remaining unsolved challenges and future strategies for further development of NCM cathode materials are outlined.

Influence of titanium on structure formation, liquation processes and microhardness of structural components of Al – Ni – Ti alloys synthesized from the oxide phases by SHS metallurgy

The paper is devoted to revealing the regularities of the influence of titanium (0.91, 2.42, 3.19, 3.39, 4.32 and 8.81 wt.%) on structure formation, nature of element distribution and microhardness of structural components in Al – Ni – Ti alloys by aluminothermy during SHS metallurgy. As the initial composition of the charge were selected the following materials in fractional parts: Al:NiO2:CaF2:NaNO3:TiO2 = 10:10:12:6:X, where X = 1.5, 4.5, 5.0, 7.0, 10.0. The structural components in Al – Ni – Ti alloys have been identified by electron microscopy and X-ray spectral analysis of elements. In the alloys with 0.91–4.32 wt.% Ti the following phases crystallize: β'-phase (solid solution of Ni in the nickel aluminide AlNi) Al3Ni2, Al3Ti, Al3Ni and α-solid solution of Ni and Ti in aluminum. In an alloy with 8.81 wt.% Ti the β'-phase turns into a titanium-doped nickel aluminide Al(NiTi) (composition in at.%: 50.53 Al; 1.47 Ti; 48.0 Ni). The increase of titanium content in Al – Ni – Ti alloys increases the solubility of Ni in the β'-phase and at titanium concentration in the alloy 8.81 wt.% in the aluminide Al(NiTi) up to 48 at.% Ni is dissolved compared to the solubility of nickel (38 at.%) in the alloy with 0.91 wt.% Ti. Increasing the nickel content in the above phases contributes to their microhardness from 13 GPa to 14.8 GPa at 8.81 wt.% Ti. Increasing the titanium content in Al – Ni – Ti alloys to 4.32 wt.% increases the solubility of nickel in the nickel aluminide Al3Ni, with a higher concentration of titanium (8.81 wt.%) in the nickel aluminide with titanium Al(NiTi) dissolves up to 48.53 at.% Ni, while in the alloy with 0.91 wt.% Ti – only about 1.0 at.% Ni. At the same time, the Al and Ti content in titanium aluminide Al3Ti decreases and its microhardness increases. It was not possible to determine the microhardness of Al(NiTi) aluminide because of the formation of a porous structure. In nickel aluminide Al3Ni, an increase in titanium content leads to an increase in nickel concentration to 4.32 wt.% Ti followed by a slight increase to 8.81 wt.% Ti. Despite increasing the nickel content and decreasing the aluminum concentration, the microhardness of the nickel aluminide decreases. Apparently, this circumstance is caused by the formation of a porous structure in this phase. The research was carried out at the Center for Collective Use “Applied Materials Science” of the Federal State Budgetary Educational Institution of Higher Education “TOGU” with the financial support of the Ministry of Science and Education of the Russian Federation within the framework of research work No state reg. of the state task AAAA-A20-120021490002-1.