Binary Solid Solutions Research Articles

Novel (Ni, Fe)S2/(Ni, Fe)3S4 solid solution hybrid: an efficient electrocatalyst with robust oxygen-evolving performance

Fabrication of high-activity electrocatalysts with operational stability is desperately needed to achieve efficient energy conversion. Herein, for the first time, we highlight a novel electrocatalyst based on binary nickel iron sulfide solid solution hybrids on carbon cloth for oxygen evolution reaction. Benefitting from the synergistic effect of varied phases and the interfacial connection between (Ni, Fe)S2 and (Ni, Fe)3S4 to accelerate the charge transport, the Ni incorporation to optimize the electronic structure of the hybrids and the downshift of the d-band center to facilitate the desorption of oxygen intermediates, the partial charge-transfer between Fe and Ni to boost the generation of catalytically active Ni3+ as well as the unique nanosphere structure to offer enough buffer area for the volume changes during constant redox reactions, the obtained binary nickel iron sulfide hybrids ((Ni, Fe)S2/(Ni, Fe)3S4) display high catalytic reactivity with a low overpotential of 210 mV to reach the current density of 10 mA cm−2, and excellent stability with negligible activity deterioration, making the hybrid a promising candidate for electrocatalytic alkaline water oxidation.

Oxygen potential calculations for conventional and Cr-doped UO2 fuels based on solid solution thermodynamics

The effect of Cr-doping on the oxygen potential of UO2 fuels was studied through a comprehensive thermodynamic treatment. Berman-type sublattice solid solutions were formulated and calibrated for UO2 (with Pu, Am, Cm, Np, La, Nd, Ce and Cr as solutes) and for a five-component noble-metal phase (Mo, Pd, Ru, Rh, Tc). Ideal gas, a binary (Sr,Ba)ZrO3 ideal solid solution and a number of stoichiometric solids were also included. The equilibrium calculations were carried out using the GEM-Selektor code with the in-house Heracles database.Ellingham diagrams were calculated for burnups between 1 and 60 GWd/tiHM over the temperature range 400 °C–1400 °C. They indicate no significant effect of Cr-doping on the oxygen potential, except at very low burnup. Oxygen potentials appear however to depend sensitively on mole fraction and non-ideality of the Mo component in the noble-metal phase. In contrast, the effect of solutes in UO2 is small. Above about 40 GWd/tiHM, the fuel oxygen potential curves converge to values exceeding by 5–30 kJ/mol the pure Mo–MoO2 buffer. Further calculations indicate that oxidation of zirconium alloy at the inner side of the cladding could considerably lower the oxygen potential.

Influence of thermomechanical loads on the energetics of precipitation in magnesium aluminum alloys

We use first principles calculations to study the influence of thermomechanical loads on the energetics of precipitation in magnesium-aluminum alloys. Using Density Functional Theory simulations, we present expressions of the energy of magnesium-aluminum binary solid solutions as a function of concentration, strain and temperature. Additionally, from these calculations, we observe an increase in equilibrium volume (and hence the equilibrium lattice constants) with the increase in concentration of magnesium. We also observe an increase in the cohesive energy of solutions with increase in concentration, and also present their dependence on strain. Calculations also show that the formation enthalpy of β phase solutions to be strongly influenced by hydrostatic stress, however the formation enthalpy of α phase solutions remain unaffected by hydrostatic stress. We present an expression of the free energy of any magnesium aluminum solid solution, that takes into account the contributions of strain and temperature. We note that these expressions can serve as input to process models of magnesium-aluminum alloys. We use these expressions to report the influence of strains and temperature on the solubility limits and equilibrium chemical potential in Mg-Al alloys. Finally, we report the influence of thermomechanical loads on the growth of precipitates, where we observe compressive strains along the c axis promotes growth of precipiates with a (0001)α habit plane, whereas strains along the a and b directions do not influence the growth of precipitates.

Investigation on the 773 K Isothermal Section of the Er-Ni-Si Ternary Phase Diagram by X-ray Powder Diffraction

The isothermal section phase diagram of Er-Ni-Si ternary system at 773 K was created by x-ray powder diffraction (XRD) analysis in this paper. Seventeen known ternary compounds ErNiSi, ErNi2Si2, ErNiSi2, Er2Ni3Si5, ErNiSi3, Er3Ni6Si2, ErNi10Si2, Er3NiSi2, ErNi2Si, ErNi5Si3, ErNi4Si, ErNi6Si6, Er33.3Ni18.7−10.7Si48−56 (Er2NiSi3), Er3Ni2Si4, Er33.3Ni8.7−4.7Si58−62 (Er4NiSi7), Er8Ni31Si11, and Er5Ni2Si3 (unknown structure type, similar to Dy5Ni2Si3) have been testified. A new compound Er37Ni3Si60 (unknown structure type) has been confirmed by excluding its XRD pattern as a superposition of nearby phase patterns. Part diffraction peaks have obvious movement with the change of Si content in Er2NiSi3 solid solution, and more moving directions are not consistent, especially at (002) and (110) planes. At the same time, quasi–binary solid solutions were detected in Er2Ni17−xSix, ErNi5−xSix, Er2Ni7−xSix, ErNi3−xSix, ErNi2−xSix, ErNi−xSix, and ErSi−xNix compounds. Other binary compounds of the Er-Ni-Si system do not show any visible solubility of the third element. If the mixture of α-ErSi2 and β-ErSi2 phases is regarded as one ErSi2 phase, the 773 K isothermal section of the phase diagram of Er-Ni-Si system consists of 55 three phase regions and ten solid solution lines.

New Method for Calculating Pairwise Effective Potential in Binary Solid Solutions

A new method for calculating the pairwise effective potential on arbitrary shells of the binary disordered solid solutions is proposed with account for the linear size effect. The method is based on the fitting of the order–disorder temperature calculated by the model potential method to its known experimental value. In disordered Cu $${}_{3}$$ Au alloy, the pairwise effective potential is calculated and the short-range order parameters on the first fourteen shells are estimated using the Krivoglaz–Clapp–Moss method. A satisfactory coincidence with the experimental data is obtained.

Binary solid solutions of anthracene and carbazole: Thermal properties, structure and crystallization kinetics

Abstract The present work explored the thermal properties, structure and crystallization kinetics of the anthracene (ANT)-carbazole (CAR) discontinuous binary solid solutions. The solid solutions with different stoichiometric ratios were synthesized by solid-state grinding or solution crystallization and characterized by differential scanning calorimetry and powder X-ray diffraction to explore their structure, morphology, and co-melting behavior. The molecular simulations results of the lattice energy of the constructed supercells also revealed the formation of ANT-CAR discontinuous solid solutions. The crystallization kinetics of the solid solutions were investigated, and the growth rate of the mixed crystals was determined using the population balance model.

Microstructural Evaluation during dissimilar transient liquid phase bonding of TiAl/Ni-based superalloy

The paper aims at understanding solidification phenomena and solid state precipitations during dissimilar transient liquid phase bonding of γ-TiAl intermetallic compound to IN718 Ni-based superalloy using a quinary Ni–7Cr–3Fe–4.5Si–3.2B (wt%) filler metal. The mechanisms of intermetallic formation via solidification and solid state reactions are discussed. The joint is featured by the formation of Ni-rich solid solution in an isothermal solidification zone near to IN718, Ni-rich solid solution and isostructural binary phases solid solution designated as Al1-xNi3Six in an isothermal solidification zone near to TiAl, boride/silicide and boro-silicide formation during binary and ternary eutectic-type solidification in an athermal solidification zone, fine nickel silicide precipitation during cooling in the joint centerline, and in-situ precipitation of Cr–Mo–Nb rich borides in a diffusion affected zone. On the other hand, Ni from the filler metal reacted with γ-TiAl base metal, leading to the formation of Ti2Ni, τ2-Al2TiNi and τ4-AlNi2Ti compounds on the reaction layer adjacent to TiAl substrate. The evaluation of different zones of the bond region showed that some brittle phases with high hardness are formed in the bond region. It was identified that the presence of the eutectic gamma solid solution between boride phases within the joint centerline can decrease the detrimental effect of the intermetallic phases on the joint toughness.

Anomalous lattice stiffening in tungsten tetraboride solid solutions with manganese under compression

Tungsten tetraboride (WB4)-based solid solutions represent one of the most promising superhard metal candidates; however, their underlying hardening mechanisms have not yet been fully understood. Here, we explore the lattice compressibility of WB4 binary solid solutions with different manganese (Mn) concentrations using high-pressure x-ray diffraction (XRD) up to 52 GPa. Under initial compression, the lattices of low and high Mn-doped WB4 alloys (i.e. W0.96Mn0.04B4 and W0.84Mn0.16B4) are shown to be more and less compressible than pure WB4, respectively. Then, a c-axis softening is found to occur above 39 GPa in WB4, consistent with previous results. However, an anomalous sudden a-axis stiffening is revealed at ~36 GPa in W0.96Mn0.04B4, along with suppression of c-axis softening observed in WB4. Furthermore, upon Mn addition, a simultaneous stiffening of a- and c-axes is demonstrated in W0.84Mn0.16B4 at ~37 GPa. Speculation on the possible relationship between this anomalous stiffening and the combined effects of valence-electron concentration (VEC) and atomic size mismatch is also included to understand the origin of the nearly identical hardness enhancement in those two solid solutions compared to WB4. Our findings emphasize the importance of accurate bonding and structure manipulation via solute atoms to best optimize the hardness of WB4 solid solutions.

Formation criterion for binary metal diboride solid solutions established through combinatorial methods

AbstractEstablishing the formation criterion is urgent for accelerating the discovery and design of solid‐solution materials with desirable properties. The previously reported formation criterion mainly focused on solid‐solution alloys, while the formation criterion was rarely established in solid‐solution ceramics. To solve this problem, herein, we take a class of solid‐solution ceramics, namely binary metal diboride ((MxN1‐x)B2) solid solutions, as a prototype. Through combinatorial methods including high‐throughput molten salt syntheses and high‐throughput first‐principles calculations combined with the machine learning approach, the correlation between influential factors, including atomic size difference (δ), mixing enthalpy at 0 K and 0 Pa (), doping condition (φ), and valence electron concentration (VEC), and the formation ability of (MxN1‐x)B2 solid solutions was first studied systematically, and then their formation criterion was well established. The results showed that the influential degree of the aforementioned four factors on the formation ability of (MxN1‐x)B2 solid solutions could be described as follows: δ > > φ > VEC. In addition, a newly proposed parameter, β, could well reflect the formation ability of (MxN1‐x)B2 solid solutions: when β > 0, the single‐phase (MxN1‐x)B2 solid solutions could be successfully synthesized in our work and vice versa. This study may provide a theoretical guidance in the discovery and design of various solid‐solution ceramics, such as the metal borides, carbides, nitrides, etc, with desirable properties.

Size-dependent Electrochemical Properties of Binary Solid Solution Nanoparticles

The electrochemical properties have different or reverse trend with decreasing radius dependent on the synthetic methods and thermodynamic states of nanoparticles. Here, a size-dependent thermodynamic model was derived to describe the thermodynamic equilibrium state of binary solid solution nanoparticles. This model combined the capillary equation with the Gibbs-Duhem equation and the Butler-Volmer equation, can simultaneously analyze nanoparticle size, stresses, solute segregation and electrochemical properties in solid solution nanoparticles. Then, spherical nanoparticles of CuZn binary solid solution were studied. With decreasing CuZn nanoparticle radius, the anodic current density decreased, whereas the equilibrium potential increased, meaning that the stability was enhanced. With increasing apparent Zn concentration, the anodic current density and the equilibrium potential difference between the CuZn nanoparticle components increased, implying that the selective corrosion of Zn atoms enhanced. These results were qualitatively consistent with some experimental observations.

Structural and dielectric properties of Lead Magnesium Niobate and Ti-doped Lead Magnesium Niobate at room temperature

Lead based relaxor ferroelectric like Lead Magnesium Niobate and their binary solid solutions with Lead Titanate have great interest of research because of their significant and excellent dielectric, piezoelectric and electrostrictive properties. In the present work, the Lead Magnesium Niobate (PMN) and Lead Magnesium Niobate-Lead Titanate (0.75PMN-0.25PT) were prepared through solid state reaction method with double sintering process at 1200 °C for 6 hr. XRD data shows the pervoskite structure of the prepared sample. SEM report of PMN and 0.75PMN-0.25PT shows the different microstructure with dense grains. Dielectric study of PMN and 0.75PMN-0.25PT shows the effect of addition of PT content on electrical properties at room temperature.

Thermodynamic Properties of Components in the Ag–Au–Pd System

The absence of consistent thermodynamic data on the systems Au–Pd, Ag–Pd, and Ag–Au–Pd prevents from interpreting the properties of alloys of these types. An approach was proposed to create models for calculating the characteristics of a ternary solid solution and binary solid solutions using a single computational apparatus. Data on the thermodynamic properties of alloys in the systems Au–Pd and Ag–Pd at certain temperatures from various experimental works and calculation models were generalized. The Redlich–Kister formalism was used to estimate the excess partial Gibbs energies and activities of components of a ternary solid solution in the Ag–Au–Pd system in the temperature range 400–1300 K. An algorithm was prepared to create calculation modules in programs for modeling natural mineral formation in systems containing Au, Ag, and Pd.

Influence of Thermomechanical Loads on the Energetics of Precipitation in Magnesium Aluminum Alloys

We use first principles calculations to study the influence of thermomechanical loads on the energetics of precipitation in magnesium-aluminum alloys. Using Density Functional Theory simulations, we present expressions of the energy of magnesium-aluminum binary solid solutions as a function of concentration, strain and temperature. Additionally, from these calculations, we observe an increase in equilibrium volume (and hence the equilibrium lattice constants) with the increase in concentration of magnesium. We also observe an increase in the cohesive energy of solutions with increase in concentration, and also present their dependence on strain. Calculations also show that the formation enthalpy of beta phase solutions to be strongly influenced by hydrostatic stress, however the formation enthalpy of alpha phase solutions remain unaffected by hydrostatic stress. We present an expression of the free energy of any magnesium aluminum solid solution, that takes into account the contributions of strain and temperature. We note that these expressions can serve as input to process models of magnesium-aluminum alloys. We use these expressions to report the influence of strains and temperature on the solubility limits and equilibrium chemical potential in Mg-Al alloys. Finally, we report the influence of thermomechanical loads on the growth of precipitates, where we observe compressive strains along the c axis promotes growth, whereas strains along the a and b directions do not influence the growth of precipitates.

Dielectric Phase Transition Behaviour Study of Dry Route Derived (BA0.5 SN0.5) TIO3 Ceramics

Ceramic materials display a wide range of properties that facilitate their use in many different product areas. Currently, there has been keen interest in the field of ceramic materials due to their excellent mechanical and physical properties. Barium Stannate Titanate (BST) is a binary solid solution system composed of ferroelectric Barium titanate and non-ferroelectric barium titanate. In this study, the phase transition behavior of (Ba1-xSnx)TiO3 (x = 0.5) (BST) ceramics was obtained by the dry-route method. The previous studies were based on Sn 2+ on the Ti site with varying values of x. The powders after calcination are compacted in the form of pellets using a hydraulic press at an optimized load above 70KN. The experimental density of our sample measured by liquid displacement method with glycerin was lower than theoretical density, giving the shape is highly dense with low porosity. The structure shows that on increasing the Sn2+ content volume decreases due to the size of Sn2+, which is smaller than that of Ba2+, in comparison to BaTiO3. As the demand of lead-free environment-friendly sensor is increasing, thus obtained BST has great applications as a sensor material in modern electronic devices.

Visible-light-induced enhanced photocatalytic degradation of Rhodamine-B dye using BixSb2-xS3 solid-solution photocatalysts

The present work examines binary solid solutions of BixSb2-xS3 [x = 0.536, 1.09, 1.68] toward photocatalytic degradation of Rhodamine-B (RhB) under visible light. Phase and microstructural analysis confirmed the formation of Bi0.536Sb1.464S3, Bi1.09Sb0.91S3, and Bi1.68Sb0.32S3 solid-solution phase with nanorods (~25–50 nm average diameter) morphology. The synthesized products show outstanding photocatalytic degradation of RhB with ~95–99.5% degradation achieved within 30 min. The kinetic study finds the high degradation efficiency (~98%) of BixSb2-xS3 photocatalysts stems from the amenable band gap (~2.3 eV, confirmed from DRS study), and higher separation efficiency of photogenerated electron-hole pairs (established from PL studies). The complete detoxification of RhB dye was confirmed by quantitative estimation of CO2 post photodegradation through GC analysis. Moreover, due to the solid and hard nature of the photocatalysts, it was easily recovered from the reaction mixture and reused multiple times without losing the degradation behavior. The parallel comparison with other active photocatalysts demonstrates BixSb2-xS3 [x = 0.536, 1.09, 1.68] have higher catalytic efficiency with similar dosing hitherto reported in the literature and possibly can be used for degradation of other organic dyes using the visible spectrum.

Composition-driven phase boundary and electromechanical properties in Bi0.5Na0.5TiO3-A(Mg1/3Nb2/3)O3 binary solid solutions

A(Mg1/3Nb2/3)O3 (abbreviated as AMN, A=Ba, Sr and Ca) complex perovskite with tolerance factor t of 0.937–1.03 was incorporated into Bi0.5Na0.5TiO3 (BNT) matrix with tBNT = 0.977 to form binary solid solutions, and the influence of dopant concentration and type on their ferroelectric and piezoelectric properties were investigated. It is found that the BNT-xCaMN system has a higher driving field, probably due to the co-contribution from smaller A-site ionic radius and larger atomic electronegativity. This study also revealed a relationship between t value of morphotropic and polymorphic phase boundary compositions for the BNT-xAMN systems and AMN end-members with tBaMN = 1.03 > tBNT, tSrMN = 0.972 ≈ tBNT and tCaMN = 0.937 < tBNT, which complements a MPB-t relation for quick predicting the approximate morphotropic and polymorphic phase boundary regions of BNT-based systems.

Thermodynamic modelling of the Fe–Sn–Zr system based on new experiments and first-principles calculations

The Fe–Sn–Zr system has been studied by first principles calculation and modelled with the Calphad method using the literature and new experimental data. The work includes a revision of Fe–Sn and Fe–Zr systems. Our experimental study has confirmed that the W5Si3 phase (stoichiometry Zr5Sn2,3Fe0,7) is stable at 1350 °C but also down to 1000 °C. Moreover, the crystal structure of the X” phase has been determined. The formation enthalpies of all the ordered configurations of the C15, C16, C36, E1a phases and the stoichiometric Fe5Sn3, Fe3Sn2, FeSn, FeSn2, Fe23Zr6, FeSn2Zr6 (θ), Fe36.36Sn36.36Zr27.27 (N) et Fe14.39Sn43.47Zr39.13 (X″) compounds have been calculated using the Density Functional Theory (DFT). The mixing enthalpies of the A1, A2 and A3 binary solid solutions have been calculated using the Special Quasirandom Structures (SQS) and DFT calculation. From these new experimental and calculated data, new thermodynamic assessments are proposed for Fe–Sn, Fe–Zr and Fe–Sn–Zr systems.

Effect of solid solution phase constitution on dissimilar Al/Cu FSW using Zn as an alloying element at the joint interface

The effect of Al/Zn/Cu binary and ternary solid solution phase constituents on metallurgical and mechanical properties of Al/Cu dissimilar friction stir welding using Zn as an alloying element was investigated. Because of Zn interlayer material binary intermetallic compounds (IMCs) such as AlCu, Al2Cu, Al.71Zn.29, CuZn5 and ternary IMCs such as Al4.2Cu3.2Zn.7 are formed. These solid solution alloying phase constituents improved the weld properties of the joint. The tensile strength was enhanced by 13% for Zn alloying specimens compared with non-alloyed weld specimen and 104% of the Al base material due to the formation of thin and controlled IMCs and solid solution phase constitution strengthening as well as Orowan strengthening. The fractured surface with Zn alloying element suggested combination of ductile–brittle fracture and indicated transgranular failure. Micro-hardness with Zn alloying specimen is higher compared to the non-alloyed specimen for the existence of different IMCs at the stir-zone. The mapping analysis indicated that the thickness of the IMCs with Zn alloying was at micro-meter level. Phase constituent revealed that thin continuous and uniformly distributed binary and ternary phases are beneficial for the enhancement of mechanical and metallurgical qualities. Macrostructural views revealed variation in IMCs flows at non-alloyed and Zn alloying cases. Different weld zone reflected grain variations and finer grain at the weld nugget due to the nucleating effect of Zn interlayer.

Change in Damping Capacity Due to Twin Boundary Segregation in Solid Solution Magnesium Alloys

The change in twin boundary mobility due to twin boundary segregation was investigated in pure magnesium and four binary solid solution magnesium alloys. The damping capacity in the vicinity of {10-12} twin boundaries were measured before and after annealing by nano-dynamic mechanical analysis. The annealing led to lower damping capacity in all magnesium alloys, which was in contrast to the results in pure magnesium. This is caused by the segregation of solute atoms in incoherent twin boundaries. The alloying element that has a characteristic of low segregation energy for twin boundaries effectively prevented the damping capacity degradation.

The Study of Crystal Structure on Grossular–Andradite Solid Solution

The effects of Al3+–Fe3+ substitution on 10 synthesized garnet samples along the grossular–andradite binary solid solution were investigated using both powder and single-crystal X-ray diffraction. Results showed that cell volume increased with andradite content. Small negative excess volume was observed in the Al-rich samples. By measuring the bond length, polyhedral volume, octahedral distortion parameter (σ), and tetrahedral rotation angle (α), we determined that the distortion occurred on the dodecahedral site. The width of the diffraction peaks was obviously related to the composition of the solid solution. Full width at half maximum of diffraction peaks was used to calculate the microstrain, which may have a relationship with enthalpy of mixing.