Liquid Alloys Research Articles

Structural Evolution of Liquid Metals and Alloys.

Low-melting liquid metals are emerging as a new group of highly functional solvents due to their capability to dissolve and alloy various metals in their elemental state to form solutions as well as colloidal systems. Furthermore, these liquid metals can facilitate and catalyze multiple unique chemical reactions. Despite the intriguing science behind liquid metals and alloys, very little is known about their fundamental structures in the nanometric regime. To bridge this gap, this work employs small angle neutron scattering and molecular dynamics simulations, revealing that the most commonly used liquid metal solvents, EGaIn and Galinstan, are surprisingly structured with the formation of clusters ranging from 157Å to 15.7Å. Conversely, non-eutectic liquid metal alloys of GaSn or GaIn at low solute concentrations of 1, 2, and 5wt%, as well as pure Ga, do not exhibit these structures. Importantly, the eutectic alloys retain their structure even at elevated temperatures of 60 and 90°C, highlighting that they are not just simple homogeneous fluids consisting of individual atoms. Understanding the complex soft structure of liquid alloys will assist in comprehending complex phenomena occurring within these fluids and contribute to deriving reaction mechanisms in the realm of synthesis and liquid metal-based catalysis. This article is protected by copyright. All rights reserved.

A review on optimum substrate surface roughness to create better wetting

Surface roughness or texture is one of the key parameters for liquid fluids or liquid metals to achieve good or poor wetting. In certain applications surface roughness of a smooth surface [mirror finish] is treated as a slippery surface for poor wettability however in a few applications’ roughness surfaces are considered as better wetting, especially for liquid metals. In this regard, to understand the parameters for the optimum surface roughness of the substrates to achieve good wetting is essential. In the present review paper, an attempt has been made to find the ideal roughness value of the substrate for better wetting of liquid metals or alloys based on substrates and fluids.

Corrosion of austenitic and ferritic steels, Kovar, and molybdenum in liquid Sb-Bi alloys with different compositions

Sb-Bi alloys may be applied as positive electrode in liquid metal batteries. In this work, the material compatibility of two steels (SS 316L and T91), Kovar 4J29, and molybdenum with SbBi9, Sb2Bi8, and Sb3Bi7 is investigated in static corrosion tests for 740 h at around 450 °C. Kovar shows severe dissolution attack (800 µm depth for SbBi9), which is mitigated at higher Sb contents due to the formation of Fe-Sb compounds. Both steels exhibit moderate corrosion depths (10–20 µm) for all Sb-Bi alloys thanks to the additional formation of stable Fe-Cr-Sb compounds. Good corrosion resistance is obtained for molybdenum.

The Promising Potential of Gallium Based Liquid Metalsfor Energy Storage.

Energy storage devices play a crucial role in various applications, such as powering electronics, power backup for homes and businesses, and support for the integration of renewable energy sources into electrical grid applications. Electrode materials for energy storage devices are preferred to have a flexible nature, conductive, better capacity, and low-toxicity. Currently, using Gallium based liquid metal alloys, such as Eutectic Gallium-Indium (EGaIn), Eutectic Gallium-Tin (EGaSn), and Eutectic Gallium-Indium-Tin (EGaInSn), as electrode materials play very important role in energy storage devices. These liquid metals have some interesting properties with a self-healing nature, high mechanical stability, compatibility with various materials, fluidity, low young's modulus, high electrical and thermal conductivity. Those properties have made it suitable to be used in various energy storage devices. In this mini review, we have concisely described the advantages and challenges of using liquid metal as electrode materials for various energy storage devices.

Irradiation-decelerated corrosion behavior of CrN/TiSiN multilayer coating in Liquid Pb-Bi eutectic alloy

CrN/TiSiN multilayer coatings deposited at 316L substrate were selected to explore the effects of irradiation on LBE (Liquid Pb-Bi eutectic alloy) corrosion. The as-deposited and irradiated coatings were exposed in LBE. After exposure, all CrN/TiSiN coatings presented oxidation accompanied with PbBi penetration. Irradiated coatings revealed better corrosion resistance with thinner oxide layer and smaller penetration thickness. The largest decrement of 39% in oxidation thickness was observed in CrN/TiSiN deposited with Ti80Si20 under 150V. The irradiation-decelerated LBE corrosion could be attributed to the rapidly formed protective oxide layer resulting from the irradiation defects which accelerated nucleation and diffusion process during oxides formation. The decelerated effect was relatively weak in coatings deposited with a bias voltage under 100 V, in which the decrement is under 10%. The enhanced corrosion resistance was attributed to the quickly formed dense and continuous chromium oxide which rapidly formed due to the irradiation induced defects and acted as diffusion barrier to slow down LBE penetration.

Enhanced Wettability of Gallium-Based Liquid Metal Alloys on Copper Films by Promoting Intermetallic Reactions

Gallium-based liquid metal alloys (LMs) have promising prospects as circuit components for flexible electronics, while, their high surface tension is now challenging for wetting of LMs on polymer surfaces and further patterning. In this study, we prepared functional Cu thin films on PDMS to enhance wettability of EGaIn liquid metal, using metal reaction-enhanced wetting. By adjusting the deposition pressure for Cu film deposition and introducing silicon-bound PDMS, both surface characteristics and microstructures of the Cu films change greatly. The corresponding contact angle of EGaIn can be tuned from 19° to 79.5°. The folded texture of the Cu film surface reduces the actual contact area, leading to an increase in the contact angle. The higher I(111)/I(200) ratio in the Cu films improves the surface wettability, probably due to the fact that the (111)-phase orientation promotes the formation of CuGa2 reaction products. This tunable wettability of LMs is expected to improve the performance of flexible electronic devices.

Bio-Inspired Electrodes with Rational Spatiotemporal Management for Lithium-Ion Batteries.

Lithium-ion batteries (LIBs) are currently the predominantenergy storage power source. However, the urgent issues of enhancing electrochemical performance, prolonging lifetime, preventing thermal runaway-caused fires, and intelligent application are obstacles to their applications. Herein, bio-inspired electrodes owning spatiotemporal management of self-healing, fast ion transport, fire-extinguishing, thermoresponsive switching, recycling, and flexibility are overviewed comprehensively, showing great promising potentials in practical application due to the significantly enhanced durability and thermal safety of LIBs. Taking advantage of the self-healing core-shell structures, binders, capsules, or liquid metal alloys, these electrodes can maintain the mechanical integrity during the lithiation-delithiation cycling. After the incorporation of fire-extinguishing binders, current collectors, or capsules, flame retardants can be released spatiotemporally during thermal runaway to ensure safety. Thermoresponsive switching electrodes are also constructed though adding thermally responsive components, which can rapidly switch LIB off under abnormal conditions and resume their functions quickly when normal operating conditions return. Finally, the challenges of bio-inspired electrode designs are presented to optimize the spatiotemporal management of LIBs. It is anticipated that the proposed electrodes with spatiotemporal management will not only promote industrial application, but also strengthen the fundamental research of bionics in energy storage.

Influence of Zr element on the atomic structure of Al-Cu alloy liquid

The relationship among chemical composition, structure and glass-forming ability in multicomponent alloys is a long-standing puzzle due to the complexity of compositions. In this work, Al77.8Cu22.2 and Al70Cu20Zr10 amorphous alloy liquids were investigated by combining high-energy X-ray diffraction at a synchrotron facility, ab-initio molecular dynamics and reverse Monte Carlo simulations. The analysis of short- and medium-range order structures of two liquid alloys show that the addition of Zr element increases the number of cluster types and makes the distribution of cluster content more uniform, and enhances the structural heterogeneity and correlation of clusters with high five-fold symmetry. These findings reveal the influence of Zr element on the atomic structure of the Al-Cu liquid alloy and deepen the understanding of Al-based metallic glasses formation.

The influence of trihaloacetic acids on the hydrogen sorption properties of palladium nanoparticles-modified AB5 alloy in aprotic ionic liquid: Towards ionic liquid-based electrolytes for hydride batteries

Binary mixtures of acetic acid/trihaloacetic acids with aprotic ionic liquid – 1-ethyl-3-methylimidazolium methanesulfonate ([EMIM][MS]) are used as electrolytes for hydrogen electrosorption measurements. Preliminary studies are performed with palladium limited volume electrode to determine optimum concentration of the acid additives for hydrogen capacity and physicochemical properties of the electrolytes. The results obtained for trichloro- and tribromoacetic acid indicate that their decarboxylation occurs after mixing with [EMIM][MS] and dissolution of palladium is observed in contact with the decomposed electrolyte. Research on hydrogen capacity of palladium nanoparticles-modified AB5-type alloy is performed in mixtures of acetic acid and trifluoroacetic acid of optimum concentration. The best electrochemical performance is demonstrated by 2 M acetic acid/[EMIM][MS] mixture. The determined value of specific capacity of the investigated hydrogen absorbing material reaches 230 mAh g−1 and is close to that previously obtained from aqueous solutions of acids or bases.

Barley Malt as a Binder for Moulding Sands—Gas Evolution and Surface Quality of Iron Castings

The requirements placed on the foundry industry are mainly related to the need to maintain an appropriate quality–price ratio of the product and to maintain an appropriate production regime that takes into account modern legal solutions related to environmental protection. This work is part of the trend of searching for new or previously unused materials from renewable sources in moulding sand technology. This article concerns the possibility of using barley malt in moulding material technology as a binding material. The presented work contains the results of research on the release of gases during casting, where high temperatures cause the decomposition of chemical substances. The tests confirmed that moulding sands with barley malt as a binder do not cause excessive emissions of harmful gaseous products when pouring moulds with liquid casting alloy. The volume of gases formed was smaller than that of commonly used moulding sands with other binders. The total volume of gases produced and the kinetics of their release indicate that casting in this type of moulding sand did not cause any technological inconvenience or casting defects of gaseous origin. This was confirmed by research involving obtaining iron castings in industrial conditions using barley malt as a binder in moulding sand technology, which were then subjected to visual assessment and roughness analysis.

Primary dendrite growth within binary Fe71Ge29 eutectic alloy under duplex levitation states

The primary β-Fe3Ge2 dendrite growth kinetics within liquid Fe71Ge29 eutectic alloy was studied by both acoustic levitation and electrostatic levitation techniques, with maximum experimental undercoolings of 130 and 143 K, respectively. At small undercoolings, (α1 + β-Fe3Ge2) eutectic growth proceeded and then transformed to lamellar (ε-Fe3Ge + β-Fe3Ge2) microstructure by peritectoid reaction. Once liquid undercooling reached 56 K, β primary phase started to nucleate preferentially and its maximum growth velocity attained 13.5 mm/s at 143 K undercooling. By acoustic levitation processing, β dendrites were distributed inside the alloy droplet. Under electrostatic levitation state, β dendrites were distributed both at the periphery and within the interior of alloy droplet, and their volume fraction was significantly higher than that under acoustic levitation. Numerical simulation results indicated that a duplex flow was induced by alloy droplet shape oscillation and acoustic streaming. The flow exhibited maximum intensity near the alloy surface, which inhibited the achievement of larger undercoolings during acoustic levitation.

Sub-5 nm ultrathin IGO film transistor printed by micro-doped InGa liquid alloy

In this study, we introduce a novel perspective that the formation of the atomically ultrathin oxide layer on the surface of liquid alloys is primarily governed by thermodynamic laws and is additionally influenced by the surface tension of the liquid alloys. In this case, we control the competition of Gibbs free energy and surface tension to effectively address the severe segregation problem of Ga2O3 and realize the precise doping of Ga2O3 in the preparation process of two dimensional IGO film through the liquid InGa alloy printing approach. Importantly, the Ga2O3 content in the IGO films can be tailored in the full range and a sub-5 nm ultrathin IGO film transistor is innovatively fabricated. The oxidation law, band gap, Fermi level, field-effect mobility, subthreshold swing, and other properties of IGO films in sub-5 nm scale are systemically investigated in detail. It has been demonstrated that the incorporation of Ga2O3 in the doping process dramatically reduced the device's turn-off current and enhanced its ability to resist ultraviolet interference. This novel doping process opens up a significant opportunity for future developments of atomically ultrathin transparent conducting film.

Mechanism behind the Controlled Generation of Liquid Metal Nanoparticles by Mechanical Agitation.

The size-controlled synthesis of liquid metal nanoparticles is necessary in a variety of applications. Sonication is a common method for breaking down bulk liquid metals into small particles, yet the influence of critical factors such as liquid metal composition has remained elusive. Our study employs high-speed imaging to unravel the mechanism of liquid metal particle formation during mechanical agitation. Gallium-based liquid metals, with and without secondary metals of bismuth, indium, and tin, are analyzed to observe the effect of cavitation and surface eruption during sonication and particle release. The impact of the secondary metal inclusion is investigated on liquid metals' surface tension, solution turbidity, and size distribution of the generated particles. Our work evidences that there is an inverse relationship between the surface tension and the ability of liquid metals to be broken down by sonication. We show that even for 0.22 at. % of bismuth in gallium, the surface tension is significantly decreased from 558 to 417 mN/m (measured in Milli-Q water), resulting in an enhanced particle generation rate: 3.6 times increase in turbidity and ∼43% reduction in the size of particles for bismuth in gallium liquid alloy compared to liquid gallium for the same sonication duration. The effect of particles' size on the photocatalysis of the annealed particles is also presented to show the applicability of the process in a proof-of-concept demonstration. This work contributes to a broader understanding of the synthesis of nanoparticles, with controlled size and characteristics, via mechanical agitation of liquid metals for diverse applications.

Calorimetric Studies and Thermodynamic Modeling of Ag-Mg-Ti Liquid Alloys.

Due to the absence of thermodynamic data concerning the Ag-Mg-Ti system in the existing literature, this study aims to fill this gap by offering the outcomes of calorimetric investigations conducted on ternary liquid solutions of these alloys. The measurements were performed using the drop calorimetry method at temperatures of 1294 K and 1297 K for the liquid solutions with the following constant mole fraction ratio: xAg/xMg = 9/1, 7/3, 1/1, 3/7 [(Ag0.9Mg0.1)1-xTix, (Ag0.7Mg0.3)1-xTix, (Ag0.5Mg0.5)1-xTix, (Ag0.3Mg0.7)1-xTix)], and xAg/xTi = 19/1 [(Ag0.95Ti0.05)1-xMgx]. The results show that the mixing enthalpy change is characterized by negative deviations from the ideal solutions and the observed minimal value equals -13.444 kJ/mol for the Ag0.95Ti0.05 alloy and xMg = 0.4182. Next, based on the thermodynamic properties of binary systems described by the Redlich-Kister model and the determined experimental data from the calorimetric measurements, the ternary optimized parameters for the Ag-Mg-Ti liquid phase were calculated by the Muggianu model. Homemade software (TerGexHm 1.0) was used to optimize the calorimetric data using the least squares method. Next, the partial and molar thermodynamic functions were calculated and are presented in the tables and figures. Moreover, this work presents, for comparative purposes, the values of the enthalpy of mixing of liquid Ag-Mg-Ti alloys, which were calculated using Toop's model. It was found that the best agreement between the modeled and experimental data was observed for the cross-sections xAg/xTi = 19/1 [(Ag0.95Ti0.05)1-xMgx] and xAg/xMg = 9/1 [(Ag0.9Mg0.1)1-xTix]. The results of the experiments presented in this paper are the first step in the investigation and future evaluation of the thermodynamics of phases and the calculation of the phase diagram of the silver-magnesium-titanium system.

Influence of the Cooling Rate on the Heterogeneity of the Structure in the Rapid Quenched Fe – Based Alloys with the Si Addition

The paper presents the results of research from the analysis of primary magnetization curves for Fe based amorphous alloys. Structural defects in the form of pseudodislocation dipoles occur in amorphous alloys. Using the theory developed by H. Kronmuller called the approach to ferromagnetic saturation, it is possible to indirectly observe internal stresses occurring in the volume of amorphous alloys. The magnetic structure is sensitive to all kinds of inhomogeneities that become visible in the process of high-field magnetization. It has been shown that the cooling rate of the liquid alloy has a great influence on the migration of atoms during the solidification process. Longer time of alloy formation causes more atoms to occupy ordered positions, which results in a change in the distance between the magnetic atoms and a higher degree of structure relaxation. This is indicated by a significant difference in the value of the spin wave stiffness parameter Dspf. The structural differences of the alloys were also investigated using a magnetic balance. It has been shown that the cooling rate influences insignificant differences in the course of thermomagnetic curves and the Curie temperature.

Conversion of CO2 into fibrous carbon materials using Ga-based liquid alloys

This study investigates the catalytic reduction of CO2 using various ratios of Ga-based liquid alloys under different conditions. We explored the alloying of liquid gallium with metals like indium (In) and magnesium (Mg) through mechanical stirring and heating. The alloys, once prepared, were exposed to CO2 in a reactor, with the Ga-In-Mg alloy demonstrating optimal reaction effects. In an exemplary synthesis, 1 g of Ga was combined with 30 wt% In and 7 wt% Mg, yielding a 7 wt% Ga-In-Mg alloy. This alloy, when reacted with CO2 for 10 h, exhibited a maximum weight gain of 445 mg. Elemental analysis showed a carbon content increase from 4.56 % to 72.56 % post-reaction. The reacted alloy, post-acid washing and electron microscopy examination, revealed the production of fibrous carbon materials approximately 7 μm wide. The primary objectives of this research were to identify the optimal temperature for CO2 reduction by the alloy and to determine the most efficient alloy catalyst using orthogonal experimental methods. Furthermore, we aimed to elucidate the catalytic mechanism of gallium-based liquid metal in CO2 reduction. The study also involved analyzing the adsorption and reaction processes by fitting the adsorption and reaction kinetic curves of the liquid metal with CO2. Achieving these objectives could enable the conversion of CO2 into solid carbon products, aligning with current environmental and sustainable development goals. This research offers new insights and innovative approaches to tackling energy-related challenges, highlighting the potential of liquid metal alloys in carbon capture and reduction applications.

Effect of Mg on healing of bifilm defects in Zn4Al melt

ABSTRACT This research explores how the presence of 0.1 wt% Mg in Zn4Al liquid alloy affects the healing of bifilm defects. Two bars in contact with each other and the atmosphere trapped between them were placed in a furnace for different times. The resulting oxide layers on the bars were then analysed using SEM, EDS, and XRD. The presence of 0.1 wt% Mg in the Zn4Al liquid caused the oxide layers to bond. The bonding started from an early stage of 8 min holding (when they were still in solid state) and continued to increase to about 30 min holding time. The bonding was attributed to the presence of Mg in the Zn4Al liquid metal, which caused the trapped atmosphere between the layers to be consumed quickly. The transformations from Al2O3 to ZnAl2O4 and ZnAl2O4 to MgAl2O4 provided potential mechanisms for the formation of bonding between the oxide layers.

A Liquid Alloy Anode for the Electrolytic Reduction of Uranium Oxide in Molten Lithium Chloride

Abstract A cost-effective anode material for uranium oxide electrolytic reduction in lithium chloride is still in deficiency. In this work, the application of liquid lithium-bismuth alloy anode was investigated. In the LiCl electrolyte at 923 K, UO2 was reduced electrochemically in cathode, while Li-Bi alloy served as counter electrode. Partial reduction of UO2 was verified by X-ray powder diffraction when the cathode potential was intentionally controlled above the lithium reduction potential. In contrast, when the precipitation of lithium metal was intentionally controlled, the reduction of UO2 was significantly improved. The charge transfer coefficient of UO2/U reaction was also calculated. Regeneration of Li-Bi alloy in LiCl-Li2O through electrolysis was proposed. Carbon, gold, and platinum had been investigated as anode materials. According to the potential variation curve, lithium was not effectively reduced into bismuth as in pure LiCl when oxygen ion was present in the molten salt. These three materials failed to demonstrate advantage in the regeneration of Li-Bi alloy.

Equation of state and thermodynamic properties of liquid Fe-O in the Earth’s outer core

Equation of state (EoS) plays a crucial role in the prediction of the composition of the outer core. Here, we calculated pressure (P)-volume (V)-temperature (T) data of liquid iron-oxygen alloys (Fe-X wt.% O, X = 0, 2.8, 6.1, and 9.9) under the outer core conditions (∼136–330 GPa, 4000–6000 K) by first-principles molecular dynamics simulations. We established an EoS for liquid Fe-O alloys with parameters including P, T, V, and O concentrations. Consequently, thermodynamic properties of liquid Fe-O alloys such as density (ρ), thermal expansion coefficient, isothermal and adiabatic bulk modulus, and sound velocity (VP) are calculated. To constrain the O content, we predicted the ρ-P and VP-P profiles along the geotherm and compared them with data from the Preliminary Reference Earth Model (PREM). We conclude that the adiabatic T profile as a function of depth affects the prediction of O content dramatically. With several anchored TICB, the composition of Fe-6.1 wt% O matches the PREM data with an acceptable range of error. But strictly speaking, the distribution in the outer core is probably uneven. In such case, we state that the O content in the outer core cannot be higher than approximately 6.1 wt%.

A DSC study of undercooling thermodynamics and crystallization kinetics for liquid Ag-Si alloys

The undercooling thermodynamics and crystallization kinetics of pure silver, hypoeutectic Ag-2%Si, and eutectic Ag-3.1%Si alloys were explored with differential scanning calorimetry. Liquid silver was highly undercooled by an extent of 200K (0.16Tm) within molten B2O3 denucleating agent. The nucleating incubation time and crystallization kinetics were investigated under isothermal condition. It was found that the crystal incubation time of nucleation generally decreased with enhanced undercooling. The analyses based on classical nucleation theory showed that heterogeneous nucleation was still dominant even at substantial undercoolings. The transformed solid fraction was derived to elucidate the crystallization kinetics of liquid silver by Johnson-Mehl-Avrami equation. The Avrami exponent was revealed to vary with liquid undercooling and crystallization extent. High cooling rate and denucleating agent were two effective ways to achieve large undercoolings for liquid Ag-Si alloys. The primary (Ag) dendrites were refined with increased undercoolings in hypoeutectic Ag-2%Si alloy. Irregular (Ag)+(Si) eutectics were the typical solidification microstructures for eutectic Ag-3.1%Si alloy at small undercoolings, while primary (Ag) dendrites displayed a remarkable volume fraction at extended undercoolings.