Liquid Metal Phase Research Articles

Distribution Behaviors of As, Sb, Bi, Sn, Se, Te, Au and Ag Between Cu and Liquid Metal Phases in the Cu-Pb Binary System at 500–1080°C

Distribution Behaviors of As, Sb, Bi, Sn, Se, Te, Au and Ag Between Cu and Liquid Metal Phases in the Cu-Pb Binary System at 500–1080°C

Thermodynamic analysis for molten corium stratification with U-Zr-O-Fe database

Aided by CALPHAD (CALculation of PHAse Diagram) method, a self-consistent thermodynamic corium database of U-Zr-O-Fe system is established based on reoptimization of key binary and ternary subsystems. According to molten corium stratification thermodynamic analysis for STFM-Fe tests in MASCA project, the corium would separate into metallic liquid phase and oxidic liquid phase due to the existence of miscibility gap and their mass fraction and composition can be well predicted. Further, the density of the oxide phase is accurately calculated by a linear fitting relationship obtained from the measured oxide density, and the density of the metal phase is calculated by the empirical formula. Thus the molten corium would exhibit a two-layer structure with a higher density metal phase below and a lower density oxide phase above. The good agreement with the STFM-Fe tests indicates the reliability of the database to analyze the molten corium stratification which tends to improve the effectiveness of in-vessel retention strategy by providing the thermodynamic prediction.

Formation, cooling history and age of impact events on the IIE iron parent body: Evidence from the Miles meteorite

Most iron meteorites formed in planetary cores during differentiation, but the IIE iron meteorites have chemical and physical features that are inconsistent with this origin. By combining mineral chemistry, mineral modes and three-dimensional petrography, we reconstruct the bulk chemistry of the felsic silicate-bearing Miles IIE iron meteorite and demonstrate that the silicate inclusion compositions are similar to partial melts produced experimentally from an H chondrite composition. We use the reconstructed bulk composition, mineralogy and thermodynamic modelling to show that melting above ∼1200°C under reducing conditions formed metal (Fe-Ni alloy) and felsic silicate partial melts. Upon cooling, the melts crystallized Mg-rich pyroxenes, Na- and K-rich feldspars, and tridymite. Importantly, this mechanism enriches cosmochemically volatile elements (i.e., those with a 50% condensation temperature of ∼430–830°C, like Na and K) to the level found in the felsic silicate inclusions.The presence of crystallographically disordered srilankite (only stable above 1160°C) and an absence of Widmanstätten texture require both high peak temperatures and rapid cooling, which cannot be explained by core formation. Instead they point to small melt volumes, a transient heat pulse, and small thermal mass, and imply efficient physical segregation of silicate and metallic melts through buoyancy separation followed by rapid cooling that arrested the separation of metal and silicate liquid phases. In situ 207Pb/206Pb age of 4542.3 ± 4.0 Ma in Zr-oxide and phosphate minerals dates the melting event that formed the silicate inclusions. This age aligns with the earliest ages found in other IIE iron meteorite silicates and requires a heating event ∼25 million years after the solar system formed. We found 39Ar/40Ar ages of 3495 ± 52 Ma (low-T) and 4303 ± 7 Ma (high-T) in a K-feldspar grain, with the 3495 Ma age aligning with later thermal events recorded in other IIE iron meteorites. Dating reveals the complex petrogenetic and thermal history of Miles and the IIE iron meteorites. This is the first IIE iron meteorite found to record evidence of heating at 4.5 and 3.5 Ga likely from impact events.We propose that high-velocity impact(s) into an iron-rich, porous chondritic parent body at ∼4.54 Ga produced immiscible metal and silicate melts that cooled rapidly and trapped low density silicate inclusions within high density metal. Other IIE irons that formed at lower peak temperatures (900–1000°C) contain chondritic silicate inclusions and relict chondrules, supporting this conceptual model. This petrogenesis is consistent with thermodynamic modelling, experimental data and the wide range of peak temperatures and cooling rates observed in the IIE iron meteorites.

Stability of the smectic phase in arrays of parallel quantum wires

Using bosonization, we study a microscopic model of parallel quantum wires constructed from two dimensional Dirac fermions in the presence of periodic topological domain walls. The model accounts for the lateral spread of the wavefunctions $\ell$ in the transverse direction to the wires. The gapless modes confined to each domain wall are shown to form Luttinger liquids, which realize a well known smectic non-Fermi liquid fixed point when interwire Coulomb interactions are taken into account. Perturbative studies on phenomenological models have shown that the smectic fixed point is unstable towards a variety of phases such as superconductivity, stripe, smectic and Fermi liquid phases. Here, we show that the considered microscopic model leads to a phase diagram with only smectic metal and Fermi liquid phases. The smectic metal phase is stable in the ideal quantum wire limit $\ell\to0$. For finite $\ell$, we find a critical Coulomb coupling $\alpha_{c}$ separating the strong coupling smectic metal from a weak coupling Fermi liquid phase. We conjecture that the absence of superconductivity should be a generic feature of similar microscopic models. Finally, we discuss the physical realization of this model with moire heterostructures.

Thermal melting of a quantum electron solid in the presence of strong disorder: Anderson localization versus the Wigner crystal

We consider the temperature-induced melting of a Wigner solid in one-dimensional (1D) and two-dimensional (2D) lattices of electrons interacting via the long-range Coulomb interaction in the presence of strong disorder arising from charged impurities in the system. The system simulates semiconductor-based 2D electron layers where Wigner crystallization is often claimed to be observed experimentally. Using exact diagonalization and utilizing the inverse participation ratio as well as conductance to distinguish between the localized insulating solid phase and the extended metallic liquid phase, we find that the effective melting temperature may be strongly enhanced by disorder since the disordered crystal typically could be in a localized glassy state incorporating the combined nonperturbative physics of both Anderson localization and Wigner crystallization. This disorder-induced enhancement of the melting temperature may explain why experiments often manage to observe insulating disorder-pinned Wigner solids in spite of the experimental temperature being decisively far above the theoretical melting temperature of the pristine Wigner crystal phase in many cases.

Paste-like recyclable Ga liquid metal phase change composites loaded with miscible Ga2O3 particles for transient cooling of portable electronics

• Miscible Ga 2 O 3 particles are introduced into Ga liquid metal to tailor thermophysical properties. • Phase change composites show low supercooling and low thermal interfacial resistance. • Paste-like composites are applied for transient cooling of USB flash disks. • Reusability and recyclability of liquid metal composites are demonstrated. With the increasing power density and continuously added functionalities, normal operation of portable electronic devices such as USB flash disks and smart phones calls for facile and efficient thermal management. Ga-based liquid metals have attracted intensive research attention for thermal management applications because of their high thermal conductivity and low toxicity, but as a type of phase change materials they still suffer from large supercooling and leakage issues. Herein, this work reports direct incorporation of high-loading miscible Ga 2 O 3 particles within Ga liquid metals to prepare non-leakage phase change composites for transient heat absorption. By loading 16.7 wt% of Ga 2 O 3 particles, paste-like liquid metal composites with a high thermal conductivity (∼21 W/m·K), a low interfacial thermal resistance (∼3.5 mm 2 ·K·W −1 ), a small supercooling degree (∼8.8 °C) and a large volumetric latent heat (∼308 J/cm 3 ) were obtained. These advantageous features enable application of the prepared liquid metal phase change composites for high-performance temporary heat absorption of intermittent-use electronic devices such as USB flash disks. Moreover, the attached phase change composites can be easily peeled off from electronic devices, and Ga liquid metals and Ga 2 O 3 particles can be readily recycled by immersing the composites within acidic or basic solutions. The facile direct hand-mixing fabrication process, broadly tailorable supercooling degree and form-stability properties, reusability and recyclability would make the prepared liquid metal composites suitable for phase change-based thermal management applications.

Thermodynamic and Experimental Study on Migration Characteristics of Heavy Metals during the Melting Process of Incineration Fly Ash

The migration characteristics of heavy metals during the melting process were one of the key factors for safe treatment and resource utilization of incineration fly ash (IFA). In this paper, the material variation of heavy metal elements of Pb, Zn, Cu, and Fe during the IFA melting process was simulated by HSC 6.0 chemistry software. The effects of melting temperature, alkalinity, atmosphere, chlorine content of raw materials, and an iron bath added to the migration characteristics, and phase transformation of selected heavy metal elements was investigated. The simulation results were also verified by experimental results. The results showed that, with the increase in temperature, the gas phase proportion of Pb, Zn, Cu, and Fe gradually increased. The alkalinity had little effect on the proportion of elements Fe and Cu in the liquid slag (LS) phase and the element Pb in the gas phase, but the increase in alkalinity could inhibit the proportion of element Zn in the gas phase. Zn mainly existed in the gas phase, and the atmosphere had little influence on the distribution of Zn. In reducing atmosphere (RA), elements Fe and Cu, which entered the liquid metal (LM) phase, were promoted, while the volatilization of Pb was restrained, which was conducive to the recovery of heavy metals. The melting process of IFA with water-washing and dechlorination had an inhibitory effect on the volatilization of Zn and Pb, but had little effect on Fe and Cu. The proportion of element Zn in the gas phase reduced from 85.84% to 9.89%. With the iron bath added in the IFA melting process, 98.42% of Cu and 82.28% of Pb entered the LM phase as metal simple substances, and 76.3% of Zn entered the gas phase as Zn (g) and ZnCl2 (g). In the experimental verification, the distribution proportions of the four heavy metals in the gas phase, LS phase, and LM phase were consistent with the simulation results.

Effect of Metal-Precursor Stacking Order on Volume-Defect Formation in CZTSSe Thin Film: Formation Mechanism of Blisters and Nanopores.

In this study, we investigated the effect of the stacking order of metal precursors on the formation of volume defects, such as blisters and nanopores, in CZTSSe thin-film solar cells. We fabricated CZTSSe thin films using three types of metal-precursor combinations, namely, Zn/Cu/Sn/Mo, Cu/Zn/Sn/Mo, and Sn/Cu/Zn/Mo, and studied the blister formation. The blister-formation mechanism was based on the delamination model, taking into consideration the compressive stress and adhesion properties. A compressive stress could be induced during the preferential formation of a ZnSSe shell. Under this stress, the adhesion between the ZnSSe film and the Mo substrate could be maintained by the surface tension of a metallic liquid phase with good wettability, or by the functioning of ZnSSe pillars as anchors, depending on the type of metal precursor used. Additionally, the nanopore formation near the back-contact side was found to be induced by the columnar microstructure of the metal precursor with the Cu/Zn/Mo stacking order and its dezincification. Based on the two volume-defect-formation mechanisms proposed herein, further development of volume-defect-formation suppression technology is expected to be made.

Electrochemical Reduction of La2O3, Nd2O3, and CeO2 in LiCl-Li2O Melt.

The reduction of pellets composed of individual CeO2, Nd2O3 and a La2O3-Nd2O3-CeO2 mixture by lithium extracted on a cathode during lithium chloride electrolysis at 650 °C was studied. The methods of cyclic voltammetry, electron microscopy, including determination of the elemental composition of the studied objects, and X-ray diffraction analysis were applied for the present study. The reduction degree of rare-earth metal (REM) oxides was determined using both the bromine method and reduction melting of the samples in the graphite crucible. The formation of the metallic phase composed of the rare-earth elements (REEs) was not observed even at the cathode potentials, corresponding to the formation of the liquid alkali metal phase, and lithium extraction, which, in the quantitative ratio, exceeds greatly the values needed for the reduction reaction. CeO2 was found to reduce to Ce2O3.

Liquid Phase 3D Printing: How This New Technology Can Help Bring 3D Printing to the Operating Room.

The purpose of this review is to discuss the state of technology in liquid phase three-dimensional (3D) metal printing, how this has affected the field of orthopedic surgery, and changes that we can expect in the future with the rise of this printing technology. We will also discuss how liquid phase metal printing can possibly bring three-dimensional printing to the operating room. The use of liquid phase 3D metal printing may become commonplace for manufacturing orthopedic implants and devices. Traditional metal printing involved powder-based metals and high-energy beam technologies that are expensive, time-consuming, and potentially wasteful. This unfortunately leaves them out of reach for most end consumers such as orthopedic surgeons. Liquid phase metal printing is less expensive and faster. However, there is still major work required to bring this technology to the operating room and benefit patients. While major strides have been made in the field of liquid phase metal three-dimensional printing, there are still significant developments in the pipeline. These could lead to future production of personalized orthopedic implants and devices with optimal material properties for patients.

SNF processing electrochemical operations: liquid-metal and salt medium purification

The paper investigates the process of regeneration of a liquid metal medium used in the pyroelectrochemical reprocessing of spent mixed uranium-plutonium nitride fuel produced by a fast neutron reactor. The investigation concerns the interaction of liquid cadmium with sludge formed during the anodic dissolution of ceramic nitride pellets in a 3LiCl-2KCl melt medium as well as the possibility of its purification by filtration from individual metal fission products. Anode sludge is represented by fission products of the platinum group, zirconium, molybdenum and technetium. It was determined by scanning electron microscopy that the metal product is composed of several intergrowth phases. It was found that upon contact of a polymetallic alloy simulating anode sludge with a melt, the liquid metal phase is saturated to 0.025 wt% of Pd, 0.01 wt% of Rh for 50 hours at 500 °C, while zirconium forms an insoluble dispersed intermetallic compound ZrCd3. Powders of molybdenum and technetium, which are not wetted with cadmium, can be completely removed using a filter mesh of plain weaving of the P-200 type. It is also possible to remove zirconium from anodic cadmium by filtration. The filtration efficiency of ruthenium and palladium powders did not exceed 54.3 and 13.1 wt%, respectively, due to partial dissolution and thinning of particles, which will lead to saturation of the liquid metal phase and the need to purify it by alternative methods.

Chemical species mixing during direct energy deposition of bimetallic systems using titanium and dissimilar refractory metals for repair and biomedical applications

Direct energy deposition (DED) is one of the additive manufacturing technologies where the metal powder is laser-melted by the nozzle and then deposited onto the metal substrate layer-by-layer. DED allows dissimilar metals to be fabricated in order to produce high-performance and intricate parts, and to utilise as a repair method of different metals as well. Refractory metals – high-density, high-melting point materials – are used for repair as a thermal shielding of titanium for high-temperature or biomedical applications. Chemical species mixing of the joint interface between Ti and Zr, Nb, Mo, Hf, Ta and W is induced by transport of species, heat and mass during the DED process. In this work, chemical species mixing, solute profile, and thermal-fluid characteristics are studied using the high-fidelity modelling of coupled powder and thermal-solutal-fluid flow dynamics to elucidate the dissimilar mixture of metals and provide insights into the manufacturability of the refractory metals using DED. It is found that low viscosity metals such as Zr and Nb show good repairability indicated by internal species mixing. Other metals also exhibit enhanced mixing when the temperature is properly set to reduce the viscosity. Therefore, consideration of convection and species mixing in the liquid metal phase is significant. Cooling rate, related to cracking, is also discussed and controlling the local cooling and subsequent solidification behaviour should be properly done by setting proper process conditions. This indicates that the computational tool is capable of predicting causal relationship between materials and processing route for DED applications. • Direct energy deposition is simulated for dissimilar Ti and refractory metals. • Powder and fluid flow simulation is used with multi-metal formulations. • Viscosity significantly affects the mixing behaviour. • Viscosity is linked with local temperature determined by process parameters. • Local temperature also affects cooling rate and thus solidification behaviour.

Mechanism of liquid-phase metal infiltration into pyridine-containing polymeric thin films

This research studied the liquid-phase selective metal infiltration of a pyridine-containing block copolymer (BCP). The results demonstrated that the metal cations interact differently with the poly(2-vinylpyridine) in polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP); the oxidation state and type of cation play an important role in the infiltration process, which is also affected by the solvent. Silver (Ag+) did not present an effective infiltration, while nickel (Ni2+) and chromium (Cr3+) were able to reproduce the pattern of the BCP. These differences can be associated with the coordination of the pyridinic nitrogen and the metal, in parallel with π-interactions. Furthermore, in the case of chromium, the presence of oxyanions led to an improved infiltration and high fidelity on the formation of the ordered metal oxide layer.

Large-Grain Spanning Monolayer Cu2 ZnSnSe4 Thin-Film Solar Cells Grown from Metal Precursor.

The persistent double layer structure whereby two layers with different properties form at the front and rear of absorbers is a critical challenge in the field of kesterite thin-film solar cells, which imposes additional nonradiative recombination in the quasi-neutral region and potential limitation to the transport of hole carriers. Herein, an effective model for growing monolayer CZTSe thin-films based on metal precursors with large grains spanning the whole film is developed. Voids and fine grain layer are avoided successfully by suppressing the formation of a Sn-rich liquid metal phase near Mo back contact during alloying, while grain coarsening is greatly promoted by enhancing mass transfer during grain growth. The desired morphology exhibits several encouraging features, including significantly reduced recombination in the quasi-neutral region that contributes to the large increase of short-circuit current, and a quasi-Ohmic back contact which is a prerequisite for high fill factor. Though this growth mode may introduce more interfacial defects which require further modification, the strategies demonstrated remove a primary obstacle toward higher efficiency kesterite solar cells, and can be applicable to morphology control with other emerging chalcogenide thin films.

Chemical interaction between uranium dioxide, boron carbide and stainless steel at 1900 °C — Application to a severe accident scenario in sodium cooled fast reactors

For the understanding of severe accidents in sodium cooled fast reactors (SFR), it is necessary to understand two prototypic accident scenarios such as ULOF (Unprotected Loss of Flow Accident) and UTOP (Unprotected Transient OverPower). As the base knowledge, it is also important to understand high temperature chemical interaction among major core materials such as MOx fuel (MOx: mixed oxide of uranium and plutonium), steel cladding and B4C neutron absorber have to be investigated. This study aims at providing experimental data on phase formation and phase-stability at various temperature and pressure conditions. A first series of samples containing a mixture of B4C and steel were prepared to obtain a homogenous metallic solid. In a second step, these metallic samples were mixed and melted with small UO2 pieces by arc melting. Then these samples underwent a heat treatment at 1900 °C for 1 hour. EDS, EBSD and EPMA analyses were performed to identify the phases formed during the solidification. In addition, thermodynamic calculations were performed for the interpretation of the results, revealing that a carbo-reduction reaction occurs: UO2 + 2 C = 2 CO + U. A significant amount of uranium from the fuel is dissolved in the metallic liquid phase, leading to the formation of mixed borides (UM3B2, UMB4, UM4B, M=Fe,Cr,Ni). In comparison with the UO2/steel interaction, the present results show that the presence of B and C in the melt improves the wetting behaviour of the metallic liquid towards UO2.

Analysis of the localized metallic phase solidification in VULCANO VF-U1 with MPS method

• MCCI analysis with MPS method has been developed with improved numerical accuracy. • The VULCANO VF-U1 experiment has been analyzed with the developed method. • Molten concrete generated by sidewall ablation dragged the metallic phase upward. • Liquid metallic phases were trapped in oxidic crust films during the cooling phase. • The final metallic phase distribution qualitatively agreed with the experiment.

Hierarchical heterostructured FeCr–(Mg–Mg2Ni) composite with 3D interconnected and lamellar structures synthesized by liquid metal dealloying

Liquid metal dealloying (LMD) has recently attracted significant attention. Because the LMD process enables the production of three-dimensional (3D) interconnected non-noble metallic materials. In addition, the metallic melt medium is useful for the development of heterostructure (HS) metal–metal composites. However, the solidified liquid metal phase (low melting point metals such as Mg, Bi, Sn, or Cu) has a much lower strength than the developed ligament phase (e.g., Fe, FeCr, Ti, etc.). In this study, the soft Mg phase was strengthened by adding alloying element of Ni. A eutectic composition of Mg–10 at.% Ni melt leads to the formation of fine eutectic structure of (Mg–Mg2Ni) within 3D interconnected morphology. This hierarchical heterostructured composite consisted of FeCr ligament and Mg–Mg2Ni lamellar, and a high yield strength of 280 MPa and a noticeable elongation (1.5%) were achieved. The complex 3D morphology of ligament and lamellar geometrically constraint each other, and it prevents the early fracture of brittle Mg–Mg2Ni lamellar phase. The alloy design for the LMD melt gives insights for hierarchical HS materials with outstanding mechanical properties for structural applications.

Visualization and modeling for water atomization of low melting point alloy

Liquid metal fragmentation by impinging fast water spray, so called water atomization, is widely used to produce metal powders efficiently. In the present paper, we conduct the high-speed visualization experiments and theoretical modeling for elucidating the mechanism of fragmentation and solidification processes, which are essentially important to control the metal powder characters. We successfully visualize the detailed sequential events from the water spray ejection, freely dropped molten metal of 42Sn-58Bi, followed by their collision, metal fragmentation in liquid phase, and solidification, leading to revealing the fragmentation processes as the impact of water spray and the vapor explosion. Quantified metal particle size convinces that the water atomization simultaneously proceeds fragmentation of metal in liquid phase with solidification. The experimental results of size distribution and mean diameter well validate the proposed physically-consistent theoretical modeling for the prediction of particle size.

Nanotip Formation from Liquid Metals for Soft Electronic Junctions.

Liquid metals and alloys with high-aspect-ratio nanodimensional features are highly sought-after for emerging electronic applications. However, high surface tension, water-like fluidity, and the existence of self-limiting oxides confer specific peculiarities to their characteristics. Here, we introduce a high accuracy nanometric three-dimensional pulling and stretching method to fabricate liquid-metal-based nanotips from room- or near-room-temperature gallium-based alloys. The pulling rate and step size were controlled with a resolution of up to 10 nm and yielded different nanotip morphologies and lengths as a function of the base liquid metal alloy composition and the pulling parameters. The obtained nanotips presented high aspect ratios over lengths of a few microns and apexes between 10 and 100 nm. The liquid metal alloys were found confined within nanotips with about 10 nm apexes when vertically pulled at 100 nm/s. An amorphous gallium oxide skin was shown to cover the surface of the nanotips, while the liquid core was composed of the initial liquid metal alloys. The electrical contact established at the nanotips was characterized under dynamic conditions. The liquid metal nanotips showed an Ohmic resistance when a continuous liquid metal channel was formed, and a controllable semiconductor state corresponding to a heterojunction formed at the junction between the liquid metal phase and the gallium oxide semiconductor skin. The variable threshold voltages of the heterojunction were controlled via stretching of the nanotips with a 10 nm step resolution. The liquid metal nanotips were also used for establishing soft electronic junctions. This novel method of liquid metal nanotip fabrication with Ohmic and semiconducting behaviors will lead to exciting avenues for developing electronic and sensing devices.

Modeling the Ga/As binary system across temperatures and compositions from first principles

Materials composed of elements from the third and fifth columns of the periodic table display a very rich behavior, with the phase diagram usually containing a metallic liquid phase and a polar semiconducting solid. As a consequence, it is very hard to achieve transferable empirical models of interactions between the atoms that can reliably predict their behavior across the temperature and composition range that is relevant to the study of the synthesis and properties of III/V nanostructures and devices. We present a machine-learning potential trained on density functional theory reference data that provides a general-purpose model for the Ga$_x$As$_{1-x}$ system. We provide a series of stringent tests that showcase the accuracy of the potential, and its applicability across the whole binary phase space, computing with ab initio accuracy a large number of finite-temperature properties as well as the location of phase boundaries. We also show how a committe model can be used to reliably determine the uncertainty induced by the limitations of the ML model on its predictions, to identify regions of phase space that are predicted with insufficient accuracy, and to iteratively refine the training set to achieve consistent, reliable modeling.