Phase diagrams of refractory bimetallic nanoalloys

Mendoza‐Pérez, Rafael; Mühl, S.

doi:10.1007/s11051-020-05035-x

Cited by 4 publications

(3 citation statements)

References 98 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At the same time, in the analysis of phase equilibria in systems of a small volume, it is necessary to take into account several characteristic features. These peculiarities manifest themselves in significant dependences of mutual solubilities of components and equilibrium volume fractions of coexisting phases on the volume [9][10][11][12][13][14][15][16][17][18][19][20], shape of a nanoparticle [12][13][14]18], thermodynamical characteristics of the surrounding environment [20] and several other factors [15,17,19]. The equilibrium phase compositions of small-volume systems are significantly different from the phase compositions of the same systems in the bulk state and can be modeled using the methods of equilibrium chemical thermodynamics [21] and several other approaches [22] (the applicability of thermodynamical methods in the analysis of phase equlibria in small-volume systems as well as their applicability limits are discussed in [23]).…”

Section: Introductionmentioning

confidence: 99%

Fractal Nanoparticles of Phase-Separating Solid Solutions: Morphology-Dependent Phase Equilibria in Tungsten Heavy Pseudo-Alloys

Shishulin

2023

Eurasian phys. tech. j.

View full text Add to dashboard Cite

In this paper, we simulate thermodynamically the morphology-dependent phase equilibria in core-shell nanoparticles of a phase-separating solid solution using the example of W-Cr heavy alloy. The morphology of a nanoparticle is described in the framework of the fractal geometry methods. Itis shown that there are two possible heterogeneous states in a nanoparticle while the compositions of phases in both states differ from each other. The dependences of mutual solubilities of components on the temperature are obtained while the behavior of these dependences significantly differs depending on the particular state and the morphology of nanoparticle under consideration. In nanoparticles of a very complicated morphology, the phase separation itself gets suppressed and the nanoparticle remains inthe homogeneous state at the temperatures significantly below the macroscopic value of the upper critical dissolution temperature. The demonstrated regularities are explained based on three mechanisms of reducing the free energy of the system and the “competition” between them. In the final section, a method for calculating the equlibrium size distributions and average characteristics of nanoparticle ensembles is described along with a technique of measuring nanoparticle fractal dimensions based on the microscopy data.

show abstract

Section: Introductionmentioning

confidence: 99%

Fractal Nanoparticles of Phase-Separating Solid Solutions: Morphology-Dependent Phase Equilibria in Tungsten Heavy Pseudo-Alloys

Shishulin

2023

Eurasian phys. tech. j.

View full text Add to dashboard Cite

show abstract

“…The compositions of co-existing phases and phase transition temperatures in nanoscale systems (nanoparticles, nanodroplets etc.) depend on the size of the system [13][14][15][16][17][18][19][20][21][22][23], its shape [16][17][18][19]22] as well as on the thermodynamical properties of all interfaces [23]. In phase diagrams, the mentioned effects can manifest themselves as significant shifts of characteristic points, shifts and deformations of characteristic lines in comparison with phase diagrams for the bulk-state systems.…”

Section: Introductionmentioning

confidence: 99%

“…In order to calculate the phase equilibria at the nanoscale by thermodynamical methods, it is necessary to minimize the total Gibbs function of the system with allowance for the contribution of all interfaces and to analyze the configuration of its minima (see [16,20,21], for example). Despite the fact that there is a set of papers observing the mentioned effects, the general regularities cannot be obtained from most of them at present due to the substantial differences in the models derived and some critical gaps.…”

Section: Introductionmentioning

confidence: 99%

Untitled

2021

Eurasian phys. tech. j.

View full text Add to dashboard Cite

Being the basis of modern electronics, silicon-germanium semiconductor alloys are widely used in a great number of fields. In this paper, the phase equilibria in Si-Ge nanoparticles have been simulated using a thermodynamical approach. Calculations show that nanoparticles of different diameters and compositions have unique sets of nanoscale liquidus and solidus temperatures which differ significantly from the reference data for the bulk alloy, and the range between nanoscale liquidus and nanoscale solidus temperatures narrows with reducing the particle size. Unlike bulk alloys, the compositions of co-existing liquid and solid phases at different temperatures dramatically differ in nanoparticles with various Si contents while the dependences of equilibrium phase compositions and volume fractions of co-existing phases on particle diameters have turned out to be different at various temperatures and atomic fractions of Si in a nanoparticle. A thermo-dynamical interpretation of the obtained results has also been given based on several mechanisms of lowering the free energy of the system.

show abstract