Ionic Charge Research Articles

Unveiling crystallographic texture in laser floating zone melted Al2O3/YAG eutectic ceramic by seed-crystal inducing

This study demonstrated the unique crystallographic features in Al2O3/YAG eutectic by seed-crystal inducing in laser floating zone melting (LFZM) process for crystallographic orientation control. The as-fabricated eutectic ceramics induced by different single crystalline seeds were mainly composed of randomly oriented Al2O3 faceted particles and irregular eutectic, as a result of the initial uncoupled growth at the junction of seed and eutectic. Specifically, along the direction of directional solidification, the eutectic ceramics grew stably with a single crystallographic orientation relationship with low planar disregistry (2 %∼6 %). The stability of phase interface with minimum interfacial strain and better ionic charge balance in Al2O3/YAG eutectic has a greater effect on the regulation of the eutectic growth orientation than the constraint of the single crystalline seed.

MXene Supported Electrodeposition Engineering of Layer Double Hydroxide for Alkaline Zinc Batteries.

The main challenges faced by aqueous rechargeable nickel-zinc batteries are their comparatively low energy density and poor cycling stability, mainly due to the limited capacity and reversibility of existing Ni-based cathodes. Moreover, the preparation procedures of these cathodes are complex and not easily scalable, which makes them less promising for large-scale energy storage. Herein, we utilized MXene as a functional additive to effectively improve the electrodeposition preparation of NiCo layered double hydroxides (LDH). Benefiting from the improved interfacial contact between nickel foam (NF) and platting solution and the enhanced ionic conductivity of platting product based on MXene additives, the resulting binder-free NiCo LDH electrode can achieve ultrahigh areal loading (~65 mg cm-2) with abundant active surface for redox reactions and maintained short transport pathway for ion diffusion and charge transfer. Furthermore, the as-fabricated alkaline NiCo LDH-based battery delivers high discharge capacity, up to 20.2 mAh cm-2 (311 mAh g-1), accompanied by remarkable rate performance (9.6 mAh cm-2 or 148 mAh g-1 at 120 mA cm-2). Due to the high structural and chemical stability of MXenes/LDH-based electrode, excellent cycling life can also be achieved with 88.6 % capacity retention after 10000 cycles. In addition, ultrahigh areal energy density (31.2 mWh cm-2) and gravimetric energy density (465 Wh kg-1) can be simultaneously achieved. This work has inspired the design of advanced cathode materials to develop high-performance aqueous zinc batteries.

Complexation of 3p-C-NETA with radiometal ions: A density functional theory study for targeted radioimmunotherapy

Bifunctional chelators (BFCs) are vital in the design of effective radiopharmaceuticals, as they are able to bind to both a radiometal ion and a targeting vector. The 3p-C-NETA or 4-[2-(bis-carboxy-methylamino)-5-(4-nitrophenyl)-entyl])-7-carboxymethyl-[1,4,7]tri-azonan-1-yl acetic acid is a novel and promising BFC, developed for diagnostic and therapeutic purposes. The binding affinity between the BFC and radiometal ion significantly impacts their effectiveness. Predicting the equilibrium constants for the formation of 1:1 radiometals/chelator complexes (log K1 values) is crucial for designing BFCs with improved affinity and selectivity for radiometals. The purpose of this study is to evaluate the complexation of Ga3+, Tb3+, Bi3+, and Ac3+ radiometal ions with 3p-C-NETA using density functional theory (B3LYP and M06-HF functional) and 6-311G(d)/SDD basis sets, where the 1,4,7,10-tetrazacyclodecane-1,4,7,10-tetracetic acid (DOTA) was employed as a benchmark. Formation of the [Ac3+(3p-C-NETA)(H2O)]- complexes is predicted to be markedly less stable compared to the other complexes, exhibiting the lowest chemical hardness and the highest chemical softness. Additionally, the chelation stability of the complexes is mainly determined by ligand-ion and ion-water interactions, which depend on the atomic charge and atomic radius of the metal ion.

Active microparticle propulsion pervasively powered by asymmetric AC field electrophoresis

HypothesisSymmetry breaking in an electric field-driven active particle system can be induced by applying a spatially uniform, but temporally non-uniform, alternating current (AC) signal. Regardless of the type of particles exposed to sawtooth AC signals, the unevenly induced polarization of the ionic charge layer leads to a major electrohydrodynamic effect of active propulsion, termed Asymmetric Field Electrophoresis (AFEP). ExperimentsSuspensions containing latex microspheres of three sizes, as well as Janus and metal-coated particles were subjected to sawtooth AC signals of varying voltages, frequencies, and time asymmetries. Particle tracking via microscopy was used to analyze their motility as a function of the key parameters. FindingsThe particles exhibit field-colinear active propulsion, and the temporal reversal of the AC signal results in a reversal of their direction of motion. The experimental velocity data as a function of field strength, frequency, and signal asymmetry are supported by models of asymmetric ionic concentration-polarization. The direction of particle migration exhibits a size-dependent crossover in the low frequency domain. This enables new approaches for simple and efficient on-chip sorting. Combining AFEP with other AC motility mechanisms, such as induced-charge electrophoresis, allows multiaxial control of particle motion and could enable development of novel AC field-driven active microsystems.

A novel Cu-MOF@Si/C prepared by the pulse discharge and hydrothermal method as an anode material for lithium-ion battery

Metal-organic framework (MOF) composite materials have attracted significant interest owing to their customizable shape and porosity. However, the widespread use of MOFs in lithium-ion batteries is limited because of its low ionic conductivity and charging capacity. In this study, Si nanospheres are synthesized using the pulse-discharge method. Subsequently, a composite of Cu-MOF-coated Si nanospheres (Cu-MOF@Si) is developed via a solvothermal process using MOF-199 as the precursor. This is followed by the synthesis of a novel Cu-MOF@Si/C composite via thermal decomposition. Cu-MOF@Si/C composites have been employed as anode materials in lithium-ion batteries. After undergoing 300 charge and discharge cycles at a rate of 100 mA g−1, the composite exhibited a capacity of 725.4 mAh g−1 and an initial Coulombic efficiency of 96.86 %. In addition, the battery showed an excellent rate performance and maintained a high discharge capacity even at current densities of 0.2, 0.5, 1.0, and 2.0 C. These findings suggest that the conductive network formed during the annealing of the Cu-MOF@Si/C composite is vital for enhancing the ionic conductivity and mitigating the expansion of Si nanoparticles during battery cycling.

Effect of Long-Range Interaction in the Modification of Surface Layers of WC–Co Samples by a Pulsed Ion Beam

The results of modification of WC–Co samples by a pulsed beam of nitrogen ions (200–300 keV, 120 ns) with an energy density of 7–8 J/cm2 are presented. It is shown that the change in the structure occurs in the near-surface layer with a thickness of 20–30 µm, which significantly exceeds the range of ions in the target (≈0.5 µm) and the depth of propagation of the thermal front during the pulse (≈1 µm). The analysis of various mechanisms of the long-range effect is carried out: the formation of a shock wave, the generation of primary radiation defects, etc. It is shown that the long-range effect is associated with the charge exchange of ions and the formation of fast atoms. The simulation of the charge exchange of ions in the gaseous layer of desorbed molecules is performed. It was found that the probability of ion charge exchange in the processes N+ + N2 → N0 and N+ + O2 → N0 significantly exceeds 100%, which indicates that the effect of irradiation by atoms was not taken into account while calculating. In contrast to ions, when the target is irradiated with atoms, the efficiency of the formation of radiation defects is much higher.

Monitoring the curing, degradation and moisture ingress into alkyl 2-cyanoacrylate adhesives using electrochemical impedance spectroscopy

Electrochemical impedance spectroscopy (EIS) was employed in an attempt to gain insight into the mechanisms of ethyl 2-cyanoacrylate (ECA) curing (polymerisation) and bonding on aluminium alloy 2024 metal. EIS can detect ionic movement, adsorption processes, charge transfer and storage occurring at an adhesive/substrate interface and/or in a bulk bond line during curing. Low-frequency capacitance measurements demonstrated sensitivity to surface polymerisation reactions and were modelled using an equivalent circuit model with two time constants in series. At a frequency of 1 kHz, changes in the dielectric polymer could be readily followed with time, confirmed by employing a crown ether to accelerate the polymerisation process. Hydrolytic degradation of poly-ECA bonds at a stainless steel interface was also investigated. An equivalent circuit model containing a number of circuit components comprising pore, charge transfer and diffusional impedances, along with polymer film, double layer and diffusional capacitances (represented by constant phase elements), was developed. Three regions were identified in the frequency domain and ascribed to processes taking place at the polymer/electrolyte and polymer/metal oxide interfaces. In short, EIS can be employed to follow the rate of polymerisation of ethyl-2-cyanoacrylate and also the degradation of the resulting polymer in saline solution.

Lithium inelastic cross-sections and their impact on micro and nano dosimetry of boron neutron capture

Objective. To present a new set of lithium-ion cross-sections for (i) ionization and excitation processes down to 700 eV, and (ii) charge-exchange processes down to 1 keV u−1. To evaluate the impact of the use of these cross-sections on micro a nano dosimetric quantities in the context of boron neutron capture (BNC) applications/techniques. Approach. The Classical Trajectory Monte Carlo method was used to calculate Li ion charge-exchange cross sections in the energy range of 1 keV u−1 to 10 MeV u−1. Partial Li ion charge states ionization and excitation cross-sections were calculated using a detailed charge screening factor. The cross-sections were implemented in Geant4-DNA v10.07 and simulations and verified using TOPAS-nBio by calculating stopping power and continuous slowing down approximation (CSDA) range against data from ICRU and SRIM. Further microdosimetric and nanodosimetric calculations were performed to quantify differences against other simulation approaches for low energy Li ions. These calculations were: lineal energy spectra (yf(y) and yd(y)), frequency mean lineal energy yF― , dose mean lineal energy yD― and ionization cluster size distribution analysis. Microdosimetric calculations were compared against a previous MC study that neglected charge-exchange and excitation processes. Nanodosimetric results were compared against pure ionization scaled cross-sections calculations. Main results. Calculated stopping power differences between ICRU and Geant4-DNA decreased from 33.78% to 6.9%. The CSDA range difference decreased from 621% to 34% when compared against SRIM calculations. Geant4-DNA/TOPAS calculated dose mean lineal energy differed by 128% from the previous Monte Carlo. Ionization cluster size frequency distributions for Li ions differed by 76%–344.11% for 21 keV and 2 MeV respectively. With a decrease in the N 1 within 9% at 10 keV and agreeing after the 100 keV. With the new set of cross-sections being able to better simulate low energy behaviors of Li ions. Significance. This work shows an increase in detail gained from the use of a more complete set of low energy cross-sections which include charge exchange processes. Significant differences to previous simulation results were found at the microdosimetric and nanodosimetric scales that suggest that Li ions cause less ionizations per path length traveled but with more energy deposits. Microdosimetry results suggest that the BNC’s contribution to cellular death may be mainly due to alpha particle production when boron-based drugs are distributed in the cellular membrane and beyond and by Li when it is at the cell cytoplasm regions.

Excellent electrochemical performance of N and Mn doped NiCo2O4 functional nanostructures: an effective approach for symmetric supercapacitor application

In supercapacitors (SCs), cobaltite spinel is considered as an excellent electrode material because it is abundant on earth, cost-effective, and theoretically capable of achieving high capacitance values. However, there are number of factors that prevent spinel cobaltite from achieving its maximum theoretical specific capacitance, including low electrical conductivity, insufficient active sites, and slow charge transport. For these reasons, it is necessary to simplify the structural and compositional design to overcome these limitations. An efficient solvothermal method followed by pyrolysis was successfully used to shape NiCo2O4 nanoflowers doped with N (Nitrogen) and Mn (Manganese). In addition to increasing the ion diffusion resistance and charge transfer resistance, N and Mn-doped NiCo2O4 provides an electrical conductivity system. The optimized N, Co, and Mn4 (NCoMn4) nanoflowers (4 wt% Mn-doped NiCo2O4) exhibits maximum specific capacitance of 269Fg−1 at 1Ag−1 current density with an exceptional retention of capacitance 92% after 5,000 uninterrupted cycles in the Na2SO4 media. The electrokinetic analysis of NCoMn4 further indicates that overall charge is stored predominantly through capacitance, as compared with other electrodes. It is also worth noting that the as-fabricated symmetric supercapacitor delivers the maximum energy density of 36.11 Whkg−1 at a power density of 1.04 kWkg−1 at 1 Ag−1 current density. This work opens a new path to develop hybrid electrodes for enhanced supercapacitor applications and will specify an efficient method for improving the charge transfer capability.

Negative Anomalies in the Atmospheric Electric Field near the Earth's Surface in Seismically Active Regions

The paper examines poorly-studied negative bay-like anomalies in the near-earth atmospheric electric field in seismically active regions at fair weather suitable for atmospheric electric observations. Observation data analysis revealed characteristic features of anomalies formation that allow us to conclude that the anomalies are associated with the deformation of near-surface rocks at tectonoseismic process. On the basis of the concept of atmospheric electricity, the source of anomalies in the electric field is a local negative space charge of small ions in the near-earth air emerged at a negative vertical gradient of electrical conductivity. It was revealed that the charge and produced negative anomalies in the electric field have deformation and emanation processes in their origin. We propose a scheme of anomalies formation and consider the role of radon and thoron in their emergence. It was found that thoron plays a more important role in some cases.

CNT Composite β-MnO2 with Fiber Cable Shape as Cathode Materials for Aqueous Zinc-Ion Batteries.

Rechargeable aqueous zinc-ion batteries (AZIBs) have developed into one of the most attractive materials for large-scale energy storage owing to their advantages such as high energy density, low cost, and environmental friendliness. Nevertheless, the sluggish diffusion kinetics and inherent impoverished conductivity affect their practical application. Herein, the β-MnO2 composited with carbon nanotubes (CNT@M) is prepared through a simple hydrothermal approach as a high-performance cathode for AZIBs. The CNT@M electrode exhibits excellent cycling stability, in which the maximum specific discharge capacity is 259 mA h g-1 at 3 A g-1, and there is still 220 mA h g-1 after 2000 cycles. The specific capacity is obviously better than that of β-MnO2 (32 mA h g-1 after 2000 cycles). The outstanding electrochemical performance of the battery is inseparable from the structural framework of CNT and inherent high conductivity. Furthermore, CNT@M can form a complex conductive network based on CNTs to provide excellent ion diffusion and charge transfer. Therefore, the active material can maintain a long-term cycle and achieve stable capacity retention. This research provides a reasonable solution for the reliable conception of Mn-based electrodes and indicates its potential application in high-performance AZIB cathode materials.

Exploring the biofilm inhibitory potential of Candida sp. UFSJ7A glycolipid on siliconized latex catheters.

Biosurfactants, sustainable alternatives to petrochemical surfactants, are gaining attention for their potential in medical applications. This study focuses on producing, purifying, and characterizing a glycolipid biosurfactant from Candida sp. UFSJ7A, particularly for its application in biofilm prevention on siliconized latex catheter surfaces. The glycolipid was extracted and characterized, revealing a critical micellar concentration (CMC) of 0.98mg/mL, indicating its efficiency at low concentrations. Its composition, confirmed through Fourier transform infrared spectroscopy (FT-IR) and thin layer chromatography (TLC), identified it as an anionic biosurfactant with a significant ionic charge of -14.8mV. This anionic nature contributes to its biofilm prevention capabilities. The glycolipid showed a high emulsification index (E24) for toluene, gasoline, and soy oil and maintained stability under various pH and temperature conditions. Notably, its anti-adhesion activity against biofilms formed by Escherichia coli, Enterococcus faecalis, and Candida albicans was substantial. When siliconized latex catheter surfaces were preconditioned with 2mg/mL of the glycolipid, biofilm formation was reduced by up to 97% for E. coli and C. albicans and 57% for E. faecalis. These results are particularly significant when compared to the efficacy of conventional surfactants like SDS, especially for E. coli and C. albicans. This study highlights glycolipids' potential as a biotechnological tool in reducing biofilm-associated infections on medical devices, demonstrating their promising applicability in healthcare settings.

Universal chemical formula dependence of ab initio low-energy effective Hamiltonian in single-layer carrier-doped cuprate superconductors: Study using a hierarchical dependence extraction algorithm

We explore the possibility to control the superconducting transition temperature at optimal hole doping Tcopt in cuprates by tuning the chemical formula (CF). Tcopt can be theoretically predicted from the parameters of the low-energy effective Hamiltonian with one antibonding (AB) Cu3dx2−y2/O2pσ orbital per Cu atom in the CuO2 plane, notably the nearest-neighbor hopping amplitude |t1| and the ratio u=U/|t1|, where U is the onsite effective Coulomb repulsion. However, the CF dependence of |t1| and u is a highly nontrivial question. In this paper, we propose the universal dependence of |t1| and u on the CF and structural features in hole doped cuprates with a single CuO2 layer sandwiched between block layers. To do so, we perform extensive calculations of |t1| and u and analyze the results by employing a machine-learning method called hierarchical dependence extraction (HDE). The main results are (a) |t1| has a main-order dependence on the radii RX and RA of the apical anion X and cation A in the block layer. (|t1| increases when RX or RA decreases.) (b) u has a main-order dependence on the ionic charge ZX of X and the hole doping δ of the AB orbital. (u decreases when |ZX| increases or δ increases.) We elucidate and discuss the microscopic mechanism of items (a) and (b). We demonstrate the predictive power of the HDE by showing the consistency between items (a) and (b) and results from previous works. The present results provide a basis for optimizing superconducting properties in cuprates and possibly akin materials. Also, the HDE method offers a general platform to identify dependencies between physical quantities. Published by the American Physical Society 2024

Compositional Metrics of Fast and Slow Alfvénic Solar Wind Emerging from Coronal Holes and Their Boundaries

We seek to understand the composition and variability of fast solar wind (FSW) and slow Alfvénic solar wind emerging from coronal holes (CHs). We leverage an opportune conjunction between Solar Orbiter and Parker Solar Probe (PSP) during PSP Encounter 11 to include compositional diagnostics from the Solar Orbiter Heavy Ion Sensor as these variations provide crucial insights into the origin and nature of the solar wind. We use potential field source surface and magnetohydrodynamic models to connect the observed plasma at PSP and Solar Orbiter to its origin footpoint in the photosphere and compare these results with the in situ measurements. A very clear signature of a heliospheric current sheet crossing as evidenced by enhancements in low first ionization potential (FIP) elements, ion charge state ratios, proton density, low Alfvénicity, and polarity estimates validates the combination of modeling, data, and mapping. We identify two FSW streams emerging from small equatorial CHs with low ion charge state ratios, low FIP bias, high Alfvénicity, and low footpoint brightness, yet anomalously low alpha particle abundance for both streams. We identify high-Alfvénicity slow solar wind emerging from the overexpanded boundary of a CH having intermediate alpha abundance, high Alfvénicity, and dips in ion charge state ratios corresponding to CH boundaries. Through this comprehensive analysis, we highlight the power of multi-instrument conjunction studies in assessing the sources of the solar wind.

Enhanced brackish water desalination in capacitive deionization with composite Zn-BTC MOF-incorporated electrodes

In this study, composite electrodes with metal–organic framework (MOF) for brackish water desalination via capacitive deionization (CDI) were developed. The electrodes contained activated carbon (AC), polyvinylidene fluoride (PVDF), and zinc-benzene tricarboxylic acid (Zn-BTC) MOF in varying proportions, improving their electrochemical performance. Among them, the E4 electrode with 6% Zn-BTC MOF exhibited the best performance in terms of CV and EIS analyses, with a specific capacity of 88 F g−1 and low ion charge transfer resistance of 4.9 Ω. The E4 electrode showed a 46.7% increase in specific capacitance compared to the E1 electrode, which did not include the MOF. Physicochemical analyses, including XRD, FTIR, FESEM, BET, EDS, elemental mapping, and contact angle measurements, verified the superior properties of the E4 electrode compared to E1, showcasing successful MOF synthesis, desirable pore size, elemental and particle-size distribution of materials, and the superior hydrophilicity enhancement. By evaluating salt removal capacity (SRC) in various setups using an initially 100.0 mg L−1 NaCl feed solution, the asymmetric arrangement of E1 and E4 electrodes outperformed symmetric arrangements, achieving a 21.1% increase in SRC to 6.3 mg g−1. This study demonstrates the potential of MOF-incorporated electrodes for efficient CDI desalination processes.

A novel Al2O3/polyvinyl pyrrolidone-coated polyethylene separator for high-safety lithium-ion batteries

In this study, a novel ceramic-polyethylene (PE) composite separator is designed and achieved by a very facile preparation strategy for high-safety lithium-ion batteries (LIBs). The optimized ceramic slurry composed of Al2O3 and polyvinyl pyrrolidone (PVP) is coated on one side of PE separator in an economically efficient way to form the novel Al2O3/PVP-PE separator. It is found that the superior PVP binder can improve the adherence of heat-resistant Al2O3 ceramic powders on the PE substrate, which significantly enhances the thermal stability of the optimized separator. The Al2O3/PVP-PE separator shows negligible shrinkage at a high temperature of 180 °C after 30 min thermal treatment. In addition, the prepared Al2O3/PVP-PE separator shows excellent wettability with electrolyte, large porosity and high liquid storage capacity, which are quite beneficial to the ionic conductivity and charge storage kinetics. Furthermore, LIBs (LiFePO4/graphite) assembled with the optimized Al2O3/PVP-PE separator shows superior electrochemical performance than LIBs assembled with bare PE separator. This study provides insight into the practical application and commercialization of novel Al2O3/PVP-PE separator for high-safety LIBs with improved electrochemical performance.

Experimental Validation on the Ionic Strength and Charge Effect in Plasma-Induced Liquid Mobility

Experimental Validation on the Ionic Strength and Charge Effect in Plasma-Induced Liquid Mobility

Investigations on MoS2 plasma by infra-red pulsed laser irradiation in high vacuum

MoS2 targets were irradiated by infra-red (IR) pulsed laser in a high vacuum to determine hot plasma parameters, atomic, molecular and ion emission, and angular and charge state distributions. In this way, pulsed laser deposition (PLD) of thin films on graphene oxide substrates was also realized. An Nd:YAG laser, operating at the 1064 nm wavelength with a 5 ns pulse duration and up to a 1 J pulse energy, in a single pulse or at a 10 Hz repetition rate, was employed. Ablation yield was measured as a function of the laser fluence. Plasma was characterized using different analysis techniques, such as time-of-flight measurements, quadrupole mass spectrometry and fast CCD visible imaging. The so-produced films were characterized by composition, thickness, roughness, wetting ability, and morphology. When compared to the MoS2 targets, they show a slight decrease of S with respect to Mo, due to higher ablation yield, low fusion temperature and high sublimation in vacuum. The pulsed IR laser deposited MoS x (with 1 < x < 2) films are uniform, with a thickness of about 130 nm, a roughness of about 50 nm and a higher wettability than the MoS2 targets. Some potential applications of the pulsed IR laser-deposited MoS x films are also presented and discussed.

Biomimetic and electrostatic self-assembled nanocellulose/MXene films constructed with sequential bridging strategy for flexible supercapacitor

Despite the two-dimensional titanium carbide MXene (Ti3C2Tx) has shown promising applications in energy storage, the inherent self-stacking and weak connectivity among nanosheets present a challenge in manufacturing robust MXene films for emerging flexible supercapacitors. Herein, inspired by the robust “soft-hard” structured exoskeletons of crustaceans, the biomimetic cellulose nanofibers (CNFs)/MXene-Al (CM-Al) film with integrated high mechanical toughness, electroconductivity and electrochemical behavior, sequential bridging with hydrogen and ionic bonds, is crafted via the facile electrostatic self-assembly strategy. The embedded CNFs guide the in-plane orientation of MXene through hydrogen bonding, forming a “soft-hard” microstructure and dramatically enhancing the mechanical toughness of CM-Al. The rigid ionic bonds established between the oxygen-containing groups on CNFs and MXene with Al3+ further elevate the mechanical strength (163.88 MPa) and act as additional electron transfer channels to impart the reinforced electroconductivity (82.63 S cm−1). Benefiting from the more active site exposure induced by the expanded MXene layer spacing after CNFs embedding and the weakened intrinsic resistance caused by the constructed ionic bonding, the assembled flexible quasi-solid-state symmetric supercapacitor with CM-Al as electrode delivers a high area capacitance (679 mF cm−2), energy density (16.2 μWh cm−2), cycling capability (85.3 % capacitance retention after 10,000 cycles) and intrinsic tolerance to various non-stretching deformations. Moreover, the selective principles for metal ions are summarized that involved a comprehensive consideration of ionic radius, charge density and basic chemical properties. This work demonstrates an accessible and feasible construction strategy for flexible composite films and provides an alternative pathway for wearable energy storage devices.

ВИЗНАЧЕННЯ ВПЛИВУ ВНУТРІШНІХ ЕНЕРГІЙ КРИСТАЛІЧНОЇ РЕШІТКИ НА ОТРИМАННЯ НАНОСТРУКТУР У ПОВЕРХНЕВИХ ШАРАХ АЛЮМІНІЄВИХ СПЛАВІВ

The paper presents the results of calculating the crystallization energy and examines its influence on the size of the nanostructured grain during ion-plasma treatment of aluminum (VD17) with oxygen and nitrogen ions. To address this task, we employ a previously proposed model, which considers the impact of individual ions on thermal conductivity and thermoelasticity in the affected area, taking into account their energy, charge, and type. Initially, we estimate the potential number of particles in the nanostructure. Then, we compute the energy required for atomizing the grain from atoms and chemical compounds. By determining the total atomization energy of the grain (Eas), we establish the necessary energy for its formation (Es = 1.1Eas). This energy enables the determination of all characteristics in the ion's action area, such as temperature, temperature rise rate, thermal stresses, strain rate, grain size, volume, and depth of the nanostructure, as well as the actual number of particles in the nanostructure. The calculations demonstrate that the crystallization energy increases the ion energy required to obtain nanostructures. At energies close to 3∙102 eV, it ranges from 0.1 to 7 eV, which can be disregarded, while at energies close to 1.6∙104 eV, crystallization energy ranges from 2.1∙102 to 1.2∙104 eV, with higher values for oxygen ions. Additionally, the calculations show that ion charge significantly affects crystallization energy; for large ion charges, it increases. All of this underscores the necessity of considering crystallization energy only at energies of 2∙103 – 2∙104 eV, allowing refinement of the technological parameters of ion-plasma treatment of aluminum alloys to increase the likelihood of obtaining nanostructures. Furthermore, the ability to determine the sizes of nanostructures allows predicting the physical and mechanical characteristics of surface layers of processed materials. These studies may be of interest to specialists involved in surface strengthening of aluminum alloy surfaces and further research into nanostructures