Growth Of Spherical Particles Research Articles

Glass-ceramics and molybdenum doping synergistic approach for Nasicon-type solid-state electrolytes

Advancing energy density, enabling lithium metal anodes, and ensuring unparalleled safety and operational reliability in lithium batteries hinge on advancing inorganic solid-state electrolytes. To overcome current impediments, we present an innovative approach that integrates glass-ceramics with a pioneering new Nasicon strategy involving molybdenum doping. In the conducted study, a series of 14Li2O-9Al2O3-38TiO2-(39-x)P2O5-xMoO3 glasses, denoted as LATPMox, along with their corresponding glass-ceramics (LATPMox-GC), have exhibited a promising characteristic as solid electrolytes. X-ray diffraction (XRD) analysis confirms the formation of the novel Mo-doped Nasicon phases in the glass-ceramics, as validated by Rietveld refinement. Examination of the crystallization kinetic behavior of the glasses reveals a three-dimensional nucleation process with spherical particle growth, featuring an activation energy of 165 kJ mol−1. Transmission Electron Microscopy TEM characterization aligns crystallization behavior with crystallite and distribution within the glass matrix, resulting in a compact and dense microstructure. The structural properties of the resultant phases are examined through FT-IR, Raman spectroscopy, and TEM-SEAD analysis. Vickers indentation tests were employed to assess the microscopic fracture toughness, and both the glass and glass-ceramics materials demonstrated favorable mechanical performance. Optical characterization using UV–visible absorption highlights the reduction of Mo6+ to Mo5+, likely occupying tetrahedral sites within the crystalline lattice. Impedance spectroscopy measurement showcases the effective promotion of ionic conductivity following Mo doping, reaching a total conductivity value of 5.50 × 10−5 Ω−1 cm−1 along with a high lithium transference number of 0.99 at room temperature for LATPMo2.6-GC glass-ceramic. This value is larger than that of many other glass-ceramics as well as that of the well-known lithium phosphorous oxy-nitride LiPON solid electrolyte whose ionic conductivity at RT is around 2 × 10−6 Ω−1 cm−1.

Hydrothermal synthesized kaolin group lamellar/spongy aluminosilicates for enhanced lead vapor capture

Developing high-temperature-resistant adsorbents with superior porous properties is crucial for safely disposing of heavy metal-containing solid waste via pyrolysis. We synthesized aluminosilicates hydrothermally and observed that acidic conditions, especially HCl (pH=2.6), favored sponge-like mineral (NC2.6) formation with a specific surface area of 500.31 m²/g and pore volume of 0.986 cm³ /g, while alkaline conditions (pH=12.0) promoted spherical particle growth. NC2.6 exhibited higher adsorption capacity compared to kaolinite and halloysite in the PbCl2 vapor adsorption, reaching a maximum of 137.68 mg/g at 700 ℃ (75.91 % stable). We examined the effect of CO2 and H2O on adsorption efficiency and explored the mechanisms using DFT and GCMC simulations. From GCMC results, CO2 negatively impacted PbCl2 adsorption due to competitive adsorption, while H2O increased adsorption content (144.24 mg/g at 700 ℃) by converting PbCl2 into oxides. DFT revealed the presence of CO2 enhanced the adsorption stability of PbCl2 via the formation of covalent bonds between O in CO2 and Pb, and active O on the aluminosilicate surface. H2O increased PbCl2 adsorption energy, as O in H2O occupied an active Al that originally formed a covalent bond with Cl, while the H formed a weak hydrogen bond with this Cl.

Insights into the Morphological Evolution of Mossy Dendrites in Lithium Metal Symmetric and Full Cell: A Modelling Study

Mossy-dendrite growth is a common phenomenon observed in many lithium metal batteries. A lattice model is presented in this work to understand the morphological changes in mossy dendrites during the plating and stripping of Li metal. The model mimics the mossy dendrite growth by incorporating nucleation and growth of spherical particles at the lattice points. The model can predict the transition between root and tip growth by merely changing the Damköhler number. The mass transfer limitations created by the initiation of the mossy phase are identified as the dominant cause of the decay in cell potential. We also investigate the effect of morphology on the formation of dead lithium during electrodissolution. This is the first attempt to combine pseudo-2D and lattice models to simulate full-cell cycles toward mossy growth.

Spherical Particles Growth with Dynamic Oscillation during Lithium Electrodeposition

In this paper, the spherical particles growth during lithium electrodeposition was investigated by directly solving the governing equations based on the Landau transformation method. The basic growth kinetic characteristics of a spherical particle during electrodeposition was studied. Predicted results show that the dynamic oscillation of the growth velocity occurs during the spherical particle growth. It was found from numerical simulations that applied electrical potential difference, electrolyte concentration, and diffusion coefficient are 3 main factors influencing the spherical growth and the existence of the dynamic oscillation state of the growth velocity during electrodeposition. The increase in both the applied electrical potential difference and the electrolyte concentration can lead to the increase of the growth velocity of the spherical particle, while the growth velocity is independent of the diffusion coefficient. Moreover, it was found that the wavelength and the amplitude of the dynamic oscillation of the growth velocity can be influenced by the applied electrical potential difference, the electrolyte concentration, and the diffusion coefficient. We determined that the dynamic competition between electrochemical reactions and ion transport in the electrodeposition is the reason for the existence of the oscillation of the growth velocity.

Formation of hollow and solid carbon spheres in thermally stressed jet fuel in the low temperature autoxidation regime

We report the formation of hollow and solid carbon spheres and spherical nanostructures by self-assembly through thermal stressing of jet fuel (Jet A-1) in the autoxidation temperature range. The characterization of Jet A-1 deposits was conducted by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS). Additionally, high resolution mass spectrometry with electro spray ionization source (ESI-MS) have been used to identify large molecular weight compounds in the mass range 350 Da to 1000 Da in the thermally stressed fuel. Fourier transform infrared (FTIR) spectroscopy analysis revealed oxygenated functional groups in the jet fuel treated by flask tests. Compositional analysis of deposit by TEM EDS and scanning transmission electron microscopy (STEM) and a high-angle annular dark field (HAADF) detector identified multiple trace metallic elements such as Cu, Fe, Zn, Sn, Mg, Al and heteroatoms S, N, O. Hollow carbon sphere formation was due to the catalytic activity of trace metals. Spherical particle growth in this method also appeared to follow Ostwald ripening mechanism. Simple flask static tests in the low temperature regime with jet fuel as hydrocarbon source without externally added catalysts thus is a novel method for hollow and solid carbon sphere synthesis and presented in this paper.

Multiwalled Carbon Nanotube Reinforced Epoxy Nanocomposites for Vibration Damping

Multiwalled carbon nanotubes (CNTs) are used as reinforcement in epoxy modified with adduct, that is, block copolymer of carboxyl-terminated butadiene acrylonitrile (CTBN) and diglycidyl ether of bisphenol A (DGEBA). Microstructure analysis reveals uniform dispersion of a phase with spherical morphology in a continuous phase. The mean diameter of the spherical particles increased with CNT and adduct content. At 30 wt % adduct, adding CNTs results in exceptional growth of spherical particles. Loss factors in the first two modes were determined by using free vibration test in cantilever mode. Significant increase in loss factor is obtained for the epoxy nanocomposites modified with 30 wt % adduct and at all wt % CNTs (i.e., 0.5, 1, and 2.5). The vibration damping mechanism in this nanocomposite is likely due to the relative sliding of spherical particles during dynamic loads, which dissipates energy. The reduction in the distance between spherical particles as well as the reduction in the elastic modulus of...

Controlled In Situ PbSe Quantum Dot Growth around Single-Walled Carbon Nanotubes: A Noncovalent PbSe-SWNT Hybrid Structure

We developed a simple method of synthesizing noncovalently linked hybrids of PbSe quantum dots (QDs) and single-walled carbon nanotubes (SWNTs). The PbSe QDs grow around the SWNTs without any linker molecule or chemical modification of the SWNTs. We are able to control the size and shape of the QDs attached to the SWNTs by varying the synthesis conditions and elucidate the three-dimensional (3D) morphology and atomic structure of the half-ring-shaped PbSe QDs bonded to the SWNTs using scanning transmission electron microscopy (STEM) tomography and high-resolution transmission electron microscopy (HRTEM). The PbSe QDs not only assemble on the SWNT bundles, but they actually grow around them. The growth of the PbSe QDs around SWNT sidewalls is favored over the growth of spherical particles in solution, probably due to dipole stabilization by the large π-electron system of the SWNTs.

Mechanism of pulse laser interaction with colloidal nanoparticles

The laser is a very powerful and very useful instru- ment in modern nanoscience and nanotechnology. The knowl- edge of the interaction mechanism of the laser beam with nanoparticles is needed to control the laser processing of dif- ferent nano-objects. It was shown that the particle heating- melting-evaporation model can be successfully applied for many phenomena arising when colloidal nanoparticle interact with pulsed laser beams. The general approach of this model is discussed in detail. The two main components of the model, light absorption by particles, and the thermodynamics of phase transitions in particulate material are considered. Special atten- tion is devoted to the correct estimation of the possible heat losses. The way in which the phase diagrams, where the differ- ent phase conditions of particle material are presented in laser fluence−particle diameter coordinates, were produced is demonstrated. It is shown how this model can be applied for understanding the mechanism of such complicated processes as particle-size reduction and submicrometer spherical particle growth, as well as other processes that occur when colloidal particles are irradiated by a pulsed laser.

Optical transparency and development of failure in quartz glass under dynamic load

Optical transmission of quartz glass is measured during loading and unloading process，and the stress was kept below their Hugoniot elastic limit. The results show that the quartz glass maintains good transparency for more than 15 μs under loading processes of 18 GPa，then it starts to lose its transparency about 07 μs after unloading，with 30% decrease of transmittance. This phenomenon，which reflects the growth and evolution of failure induced by unloading process in quartz glass，has been explained reasonably by the growth of spherical particles and the scattering model. The results are different from the explanation of liquid-solid phase transition given in literature［J. Chem. Phys. 2004，121 9050］. This paper is significant for studying the transparency of other transparent material.

Analysis of the Growth Mechanism of Coprecipitated Spherical and Dense Nickel, Manganese, and Cobalt-Containing Hydroxides in the Presence of Aqueous Ammonia

Spherical and dense metal hydroxides were synthesized with a coprecipitation reaction in the presence of aqueous ammonia. The growth of the particles was studied by tracking the tap density and morphology with reaction time. The dependence of pH on the tap density and morphology of the particles synthesized in the coprecipitation reaction was determined for Ni(OH)2, Ni1/2Mn1/2(OH)2, and Ni1/3Mn1/3Co1/3(OH)2 The pH range at which particle growth occurred varied for the different metal hydroxides. Solving the chemical equilibria present in the coprecipitation reaction revealed that the pH range at which spherical particle growth occurred was due to the presence of metal coordinated with ammonia. On the basis of the experiments and analysis presented here, the metal hydroxide particle growth occurs by a dissolution−recrystallization type mechanism during synthesis.

Morphology control of MSU-1 silica particles

Mesoporous silica, MSU-1 with spherical morphology was prepared using TEOS (tetraethylorthosilicate) as a silica source in the presence of an alkyl polyethylene oxide surfactant via the novel two-step process proposed by Prouzet’s group: hydrolysis of TEOS conducted in highly acidic condition at room temperature followed by condensation promoted by fluoride salt addition at 35 °C. The particles produced were characterized by XRD, SEM, and N 2 adsorption/desorption isotherm. Static condensation period was found to be essential to have spherical morphology. Growth of spherical particles and evolution of porosity were studied as a function of time, temperature, NaF/TEOS, and TEOS/surfactant ratio. The MSU-1 particles prepared under different synthesis conditions were briefly tested for chromatographic separation of selected organic molecules, which demonstrates the governing influence of the pore size in MSU-1 on retention time.

Spheroidal particle stability in semisolid processing

A model for diffusion-controlled spherical particle growth is presented and solved numerically, showing how, on cooling at a sufficient rate from a given fraction solid, growth velocity first increases and then decreases rapidly when solute fields of adjacent particles overlap. An approximate analytical solution for the spherical particle growth velocity is then developed and shown to be valid until the solute fields begin to overlap. A particle stability model is next presented, building on the preceding analytic solution. This model permits prediction of the maximum cooling rate at which a semisolid slurry or reheated semisolid billet can be cooled while still retaining the spherical growth morphology. The model shows that particle stability is favored by high particle density, high fraction solid, and low cooling rate. The predictions of the stability model are found to be in good quantitative agreement with experimental data collected for Al-4.5 wt pct Cu alloy. Engineering applications of the results obtained are discussed.

A Model for Particle Dissolution and Precipitation in HSLA Steels

Precipitation of carbonitrides has been studied in as-cast slabs of one Nb and one Nb and Ti containing HSLA steel. The precipitates have been quantified using LOM and TEM. The measured size and number distributions was then compared to model calculations of precipitate nucleation and growth using estimates of the cooling rates in the austenitic range (1490oC to 800oC) during casting. Both average size and number distributions could be modelled with good agreement using identical model parameters (except for individual diffusion coefficients for the participating species). The model is based on classic nucleation rate theory and a quasistationary approximation for growth of spherical particles. Local equilibrium is assumed at the phase boundary.

Kinetics of the crystallisation of Ni–Zn ferrite powders prepared by the hydrothermal method

Recently published data on the precipitation of Ni–Zn ferrite powders prepared by the hydrothermal method have been analysed in a manner consistent with Avrami theory. The results indicate that the value of the time exponent is due to the growth of spherical particles in a solution which becomes progressively depleted of reactants. The analysis also indicates that the process can be considered to be one in which the particles all start growth from the initiation of the reaction.

Particle nucleation in turbulent gas jets

Experiments were conducted to test the theory of nucleation-controlled growth of spherical particles in a turbulent jet. Dibutyl phthalate (DBP) particles were formed in a bench-scale jet apparatus with nozzle diameters 0.235 cm and 0.375 cm. Size distributions and number concentrations of the particles were measured at different DBP vapor concentrations, jet velocities, and positions. There is evidence that the DBP particle nucleation was confined to the shear layer of the jet and that the particles grew by condensation as they moved away from the nozzle. Trends in the data suggest that for low rates of particle formation in jets, the final aerosol concentration can be predicted from simple scaling laws.

Embedded Gold Clusters: Growth in Glass and Optical Absorption Spectra

ABSTRACTOptical absorption of nanosized particles in glass was measured. The plasma absorption band was completely spread out for particles below about 1.5 ran in diameter, as also has been found by gold particles in water and a polymer. The growth kinetics suggested growth of spherical particles controlled by diffusion of gold from the matrix to the particles, and a constant number of growing particles, giving a narrow size distribution of particles. For particles below about one ran in diameter (31 gold atoms), the optical absorption was proportional to λ−4, as expected if the absorption results from free electrons in the particles.

Growth rate of condensed particles with arbitrary Knudsen numbers

A theory is developed for the growth of spherical particles in their own vapor in the case of arbitrary Knudsen numbers. Use is made of a gas-kinetic analysis based on solution, by the Lees method, of the kinetic Boltzmann equation with the collision integral in Boltzmann form. A numerical analysis is made of the effect of different parameters on growth rate.

Finite sample size effects in transformation kinetics

The effect of finite sample size on the kinetic law of phase transformations is considered. The case where the second phase develops by a nucleation and growth mechanism is treated under the assumption of isothermal conditions and constant and uniform nucleation rate. It is demonstrated that for spherical particle growth, a thin sample transformation formula given previously is an approximate version of a more general transformation law. The thin sample approximation is shown to be reliable when a certain dimensionless thickness is small. The latter quantity, rather than the actual sample thickness, determines when the usual law of transformation kinetics valid for bulk (large dimension) samples must be modified.

An extension of polymer crystallisation kinetics to a branching mechanism for spherulitic growth

AbstractThe initial stages in the development of spherulites from primary nuclei to spherical arrays of branching fibrils are included in the kinetics of polymer crystallisation. Since most of the experimental isotherms exhibit the required time dependence only over a limited range it is considered that the model has little use, and these initial stages in the development of spherulites have little effect on the degree of fit of the experimental isotherms to the Avrami rate equation.The general time dependences of crystallisations developing as a branching process is outlined and compared with that of the Avrami equations for growth of spherical particles.

Kinetics of precipitate growth in the copper-chromium system

The growth kinetics of chromium in a Cu-0.35 wt % Cr alloy were studied. At low temperatures and short ageing times the particle morphology was spherical; at higher temperatures and longer ageing times rod-shaped body-centred cubic chromium was first found to form preferentially at dislocations and grain boundaries and later in the body of the material.The growth of spherical particles obeys a t1/3 law. An activation energy for the growth kinetics of 48.1 kcal/g atom was also found. Both data indicate that a diffusion-controlled process applies to the growth of metastable particles.Attempts to obtain reliable values of the copper-chromium interfacial free energy were limited by the lack of diffusion data of chromium in copper as well as by the equilibrium solubility. Résumé L'auteur a étudié la cinétique de croissance du chrome dans un alliage de Cu contenant 0.35% poids de Cr. A basse température et pour des temps de vieillissement courts, les particules ont une forme sphérique; à plus haute température et pour des temps de vieillissement supérieurs, des bâtonnets de chrome cubique centré se forment, d'abord préférentiellement aux dislocations et aux joints de grains puis dans la matrice.La croissance des particules spheriques suit une loi en t1/3 et l'énergie d'activation pour la cinétique de croissance a été mesurée comme étant 48.1 kcal/atome g. Ces deux résultats indiquent que la croissance des particles métastables se fait par un processus contrôllé par la diffusion.Des tentatives faites pour obtanir des données valables sur l'énergie libre des interfaces Cu-Cr n'ont pas donnés entière satisfaction car on manquait de données sur la diffusion du chrome dans le cuivre et sur la solubilité à l'équilibre.