Peculiarities of LaFeO3 nanocrystals formation via glycine-nitrate combustion

Bachina, A. K.; Иванов, В. А.; Попков, В.И.

doi:10.17586/2220-8054-2017-8-5-647-653

Cited by 19 publications

(22 citation statements)

References 27 publications

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“…It is known that by varying the Red / Ox composition of the reaction mixture, it is possible to control the type of combustion and synthesis temperature, composition, morphology, microstructure and electromagnetic parameters of the resulting combustion products [25]. In turn, a change in the redox environment is possible both by choosing various types of reducing agents (glycine, urea, citric acid, etc.)…”

Section: Resultsmentioning

confidence: 99%

Effect of the Red / Ox ratio on the structure and magnetic behavior of Li0.5Fe2.5O4 nanocrystals synthesized by solution combustion approach

et al. 2019

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In this research, nanocrystalline lithium ferrite (Li 0.5 Fe 2.5 O 4 ) was synthesized using the solution combustion approach with using glycine as fuel and a chelating agent at various Red / Ox ratios ("glycine to nitrate" ratio G / N = 0.4, 0.6, 0.8, 1.0). According to the data of energy-dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS), the prepared samples correspond in their composition to stoichiometric ferrite Li 0.5 Fe 2.5 O 4 within the error of the determination methods used. The results of powder X-ray diffractometry (PXRD) confirmed the formation of α-Li 0.5 Fe 2.5 O 4 at G / N ratio of 0.8 and 1.0 and the presence of β-Li 0.5 Fe 2.5 O 4 modification in case of deficiency (G / N = 0.4) and stoichiometry (G / N = 0.6) of the chelating agent. It is shown that a change in the Red / Ox composition of reacting solutions affects not only the phase composition of the synthesized lithium ferrite samples, but also the crystallite size, which lies in the range from 22 to 35 nm. Based on the scanning electron microscopy (SEM) data, it was found that Li 0.5 Fe 2.5 O 4 powders had a developed porous microstructure consisting of micron agglomerates. According to the vibration magnetometry data of nanocrystalline lithium ferrite powders, it follows that all synthesized compositions have a pronounced ferrimagnetic behavior, despite the presence of β-modification in some of them. It is shown that by varying the Red / Ox environment and, as a consequence, the phase composition and crystallite size, it is possible to obtain Li 0.5 Fe 2.5 O 4 nanocrystals with magnetic parameters in the following ranges: saturation magnetization (M s ) = 51.6 -61.9 emu / g, residual magnetization (M r ) =14.3 -17.8 emu / g, coercive force (H c ) =109 -135 Oe.

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Section: Resultsmentioning

confidence: 99%

Effect of the Red / Ox ratio on the structure and magnetic behavior of Li0.5Fe2.5O4 nanocrystals synthesized by solution combustion approach

et al. 2019

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“…Even dimers are such, and one can consider the distribution function by these parameters [58]. And, of cause, very often, it is needed to investigate the distribution function by sizes and other parameters with its value, which is not only number or concentration of particles [29]. In these cases the distribution functions can have interesting plots [29].…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

“…And, of cause, very often, it is needed to investigate the distribution function by sizes and other parameters with its value, which is not only number or concentration of particles [29]. In these cases the distribution functions can have interesting plots [29]. And certainly, distribution functions of single initial particles (molecules, atoms, etc.)…”

Section: Discussion Of the Resultsmentioning

confidence: 99%

“…In order to describe the particle size distribution of powders, basically, four formulas are used in practice [22]: the Gorden-Andreev [22,23], the Rozin-Rammlar-Bennett [24], [22], the normal [25][26][27][28][29] or lognormal [25][26][27][28][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] distributions. In other research [27,36,37], it is considered the issue that distributions with only two parameters are insufficient.…”

Section: The Parameters Of Modeling Distribution Functions Of Particlmentioning

confidence: 99%

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Approaches to determining the kinetics for the formation of a nano-dispersed substance from the experimental distribution functions of its nanoparticle properties

Adzhiev¹,

Мелихов²,

Vedenyapin³

2019

Nanosystems: Phys. Chem. Math.

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In the present paper, we discuss the kinetic equations for the evolution of particles of a nanodispersed substance, distinguishing by properties (sizes, velocities, positions, etc.). The aim of the present investigation is to determine the coefficients for the equations by the distribution functions, which are obtained experimentally. The experiment is characterized by the time interval, which is needed for the measurement of the distribution function. However, the nanodispersed substance is obtained from a highly supersaturated solution or vapor and this time interval is large, thus, one is able to measure distribution functions only when the processes of the integration and the fragmentation of the particles become rather slow. So it is advisable to reconstruct the kinetics for the formation of a nanodispersed substance by the experimental distribution functions measured when the processes are rather slow. The first problem that arises is the obtaining of correct equations, and, hence, the derivation of the equations from each other. From the discrete system of equations for the evolution of discrete distribution functions of particles of a nanodispersed substance, we obtain the continuum equation of the Fokker-Planck type, or of the Einstein-Kolmogorov type, or of the diffuse approximation on the distribution function of nanoparticles distinguishing by the numbers of molecules forming them. We consider the distribution functions, which approximate the experimental data. We determine the coefficients for the equation of the Fokker-Planck type by the stationary and non-stationary distribution functions of a nanodispersed substance. Due to unity of the kinetic approach, the present work may be useful for specialists of various areas, who study the evolution of structures (not only with nanosize) with differing properties.

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“…Another important property of the nonautonomous finite-thickness phase is its melting point. If early papers [75,78,80,81,117,118] provided discussion that the melting temperature of surface (nonautonomous) phases may differ from the melting temperature of volume phases of the same composition, the recent papers generally consider only the value of these differences and expressions describing the dependence of the melting temperature of different nonautonomous phases on certain parameters [13,15,95,[97][98][99]108,214]. Information on the component distribution between the nonautonomous and volume phases, which makes it possible to predict the material properties and behavior over a wide temperature range, is of great importance for the analysis of polycrystalline and other disperse systems [78,79,117].…”

Section: Status Of Nonautonomous Phases and Materials With The High Vmentioning

confidence: 99%

Thermodynamics and kinetics of non-autonomous phase formation in nanostructured materials with variable functional properties

Коваленко¹,

Тугова²

2018

Nanosystems: Phys. Chem. Math.

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The review addresses physico-chemical aspects of interaction between macro-, micro-and nano-structured units of matter with the analysis of interface and grain boundary entities (nonautonomous phases) mechanisms and formation, as well as methods of their control in order to achieve the desired functional properties of nanostructured materials. Construction of these materials involves identification of thermodynamic and kinetic regularities in the organization processes, state and genesis parameters of nonautonomous phases formed as specific nanosized structures in a limited space between the macroscopic volume phases and with the limited amount of substance, which differ significantly on their properties, structure and composition from the appropriate characteristics of volume phases. Studying them is based on the application and development of theoretical and experimental methods of non-equilibrium thermodynamics, chemical kinetics, nonlinear dynamics and fractal analysis to determine the conditions of self-organization or materials directed synthesis with a high content of nonautonomous phases.

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Peculiarities of LaFeO3 nanocrystals formation via glycine-nitrate combustion

Cited by 19 publications

References 27 publications

Effect of the Red / Ox ratio on the structure and magnetic behavior of Li0.5Fe2.5O4 nanocrystals synthesized by solution combustion approach

Effect of the Red / Ox ratio on the structure and magnetic behavior of Li0.5Fe2.5O4 nanocrystals synthesized by solution combustion approach

Approaches to determining the kinetics for the formation of a nano-dispersed substance from the experimental distribution functions of its nanoparticle properties

Thermodynamics and kinetics of non-autonomous phase formation in nanostructured materials with variable functional properties

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