Application Of Liquid Metals Research Articles

Development of a Compact Multivariable Sensor Probe for Two-Phase Detection in High Temperature PbLi–argon Vertical Columns

Liquid gas two phase flow is a common occurrence in various industrial applications. For nuclear fusion applications with a Li based breeder, existence of two phase flow may lead to critical issues including decreased tritium breeding ratio, generation of hot spots and improper nuclear shielding. Additionally, a very large density ratio of liquid metal to gas mandates relevant experiments towards development and validation of software tools. PbLi has gained immense focus for its various advantages and is utilized in several breeding blanket concepts. In view of above mentioned requirements, a two phase detection tool is imperative for liquid PbLi environment. For liquid metal applications, electrical conductivity based probes are most suitable in terms of ruggedness, fabrication ease and operational simplicity. However, corrosive nature and high operational temperature for PbLi put severe demands on electrical insulation, a foremost requirement for electrical conductivity based schemes. In this study, a multivariable probe based on electrical conductivity and temperature measurement schemes is developed using Al2O3 coating as electrical insulation. Developed probe is validated in PbLi/Ar vertical column with bulk PbLi temperature upto 400 degC and time averaged void fraction upto 0.95 covering flow regimes from dispersed bubbly flow upto in box loss of coolant accident. Developed probe provides high reliability and excellent temporal resolution towards individual bubble detection through electrical conductivity based principle alongwith simultaneous two phase temperature trends. Present paper provides details about sensor probe fabrication, calibration, two phase test facility, void fraction estimations, bubble frequency and bubble residence time estimations alongwith critical observations from preliminary experimental investigations.

Applications of liquid metals in nanotechnology.

Post-transition liquid metals (LMs) offer new opportunities for accessing exciting dynamics for nanomaterials. As entities with free electrons and ions as well as fluidity, LM-based nanomaterials are fundamentally different from their solid counterparts. The low melting points of most post-transition metals (less than 330 °C) allow for the formation of nanodroplets from bulk metal melts under mild mechanical and chemical conditions. At the nanoscale, these liquid state nanodroplets simultaneously offer high electrical and thermal conductivities, tunable reactivities and useful physicochemical properties. They also offer specific alloying and dealloying conditions for the formation of multi-elemental liquid based nanoalloys or the synthesis of engineered solid nanomaterials. To date, while only a few nanosized LM materials have been investigated, extraordinary properties have been observed for such systems. Multi-elemental nanoalloys have shown controllable homogeneous or heterogeneous core and surface compositions with interfacial ordering at the nanoscale. The interactions and synergies of nanosized LMs with polymeric, inorganic and bio-materials have also resulted in new compounds. This review highlights recent progress and future directions for the synthesis and applications of post-transition LMs and their alloys. The review presents the unique properties of these LM nanodroplets for developing functional materials for electronics, sensors, catalysts, energy systems, and nanomedicine and biomedical applications, as well as other functional systems engineered at the nanoscale.

A core-shell liquid metal-Cu nanoparticle with glutathione consumption via an in situ replacement strategy for tumor combination treatment of chemodynamic, microwave dynamic and microwave thermal therapy.

The presence of high content glutathione (GSH) provides an effective "protective shield" for tumor cells, which undoubtedly is a huge impediment to reactive oxygen species (ROS)-based treatment. Fortunately, divalent copper (Cu2+) can not only consume GSH, destroying the protection mechanism of GSH, but also can be reduced to Cu+ with excellent Fenton-like reaction activity. Hence, capitalizing on the properties of liquid metals, we introduced Cu with three different valances via an in situ replacement reaction. A stable core-shell liquid-metal based "Cu storage pool" was obtained. It can effectively deplete GSH within the cells, and simultaneously produce ·OH through a Fenton-like reaction, further improving the effect of chemodynamic therapy (CDT). Under microwave irradiation, it is also capable of producing a large amount of ROS to promote tumor treatment. In addition, the loading of ionic liquid endows LZC@IL nanoparticles with certain microwave heating performance, which is able to augment microwave thermal therapy (MWTT). With the combination of CDT, microwave dynamic therapy (MDT) and MWTT, LZC@IL has an excellent effect on tumor elimination. This work offers a new idea for the application of liquid metals and the combined treatment of tumors, which has potential application value.

Experimental investigations on electrical-insulation performance of Al2O3 coatings for high temperature PbLi liquid metal applications

Electrical-insulating coatings are of great importance for applications in liquid metal breeder/coolant based systems relevant to nuclear fusion power plants. In specific to lead–lithium eutectic (Pb-16Li), a candidate breeder material, such coatings are being actively investigated worldwide for their criticality in addressing various functionalities including, but not limited to, reduction in Magneto-Hydro Dynamics (MHD) pressure drop, corrosion resistance to structural materials and development of specific diagnostics, like two-phase detection techniques. For such applications, a candidate coating must be demonstrated for its compatibility with corrosive media, endurance towards high operational temperatures and integrity of electrical-insulation over long operational durations without substantial degradation. Further, quantitative performance assessment of coated substrates within PbLi environment over long operational durations is rendered difficult due to scarcity of relevant in-situ insulation resistance data. To address this shortfall, a preliminary experimental study was performed at Institute for Plasma research (IPR) towards application of AlPO4 bonded high-purity alumina (Al2O3) coatings on SS-316L substrates and further rigorous validation in static PbLi environment. The adopted coating process required a low temperature heat treatment (<430 °C) and could yield average coating thicknesses in the range of ∼ 100 µm – 500 µm. Coated samples were validated for their electrical-insulation integrity in static PbLi over two test campaigns for continuous durations of over 700 h and 1360 h, including thermal cycling, at operational temperature in the range of 300 °C-400 °C. Volumetric electrical-resistivity, estimated through high-voltage insulation resistance measurements at relevant temperatures, remained of the order of 109-1011 Ω-cm without significant degradation. In-situ estimations of thermal derating factors establish good electrical-insulation characteristics after long term exposure to liquid PbLi. This paper presents details of utilized coating application methods, coating thickness estimations, liquid metal test set-up, insulation performance and critical observations from SEM/EDX and XRD analysis on the tested samples.

Conversion of Polymer Surfaces into Nonwetting Substrates for Liquid Metal Applications.

Liquid metal-based applications are limited by the wetting nature of polymers toward surface-oxidized gallium-based liquid metals. This work demonstrates that a 120 s CF4/O2 plasma treatment of polymer surfaces-such as poly(dimethylsiloxane) (PDMS), SU8, S1813, and polyimide-converts these previously wetting surfaces to nonwetting surfaces for gallium-based liquid metals. Static and advancing contact angles of all plasma-treated surfaces are >150°, and receding contact angles are >140°, with contact angle hysteresis in the range of 8.2-10.7°, collectively indicating lyophobic behavior. This lyophobic behavior is attributed to the plasma simultaneously fluorinating the surface while creating sub-micron scale roughness. X-ray photoelectron spectroscopy (XPS) results show a large presence of fluorine at the surface, indicating fluorination of surface methyl groups, while atomic force microscopy (AFM) results show that plasma-treated surfaces have an order of magnitude greater surface roughness than pristine surfaces, indicating a Cassie-Baxter state, which suggests that surface roughness is the primary cause of the nonwetting property, with surface chemistry making a smaller contribution. Solid surface free energy values for all plasma-treated surfaces were found to be generally lower than the pristine surfaces, indicating that this process can be used to make similar classes of polymers nonwetting to gallium-based liquid metals.

Biomimetic surface strategy of spectrum-tailored liquid metal via blackbody inspiration for highly efficient solar steam generation, desalination, and electricity generation

Solar steam generation as a promising strategy has attracted more and more attention owing to its applications of the water purification which meet the demand of clean water worldwide. Photothermal material, as the key component of solar evaporators, has aroused great interest in the design of extraordinary photothermal conversion efficiency. Herein, liquid metal was the first time used to develop a photothermal promotor with the tailored spectrum via the dipole layer strategy for highly efficient solar steam generation. As the proof-of-concept, cellulose nanocrystals were applied as bonding agent of matrix scaffold and photothermal layer for the successful preparation of the lignin-based aerogel evaporators. Inspired by the seedless sunflower, binary configurations of interior topology and surface topography was manipulated on the layer-doubled lignin-based aerogels with inverted pyramid veneer for the favorable multi-functionalities, which could hardly realize within the entirety before. The blackbody-inspired aerogel evaporators showed exceptional solar evaporation efficiency of 94% under 1 sun, and the depuration and desalination efficiency up to 99% in the sewage (water containing Zn2+, Ni2+, Cu2+, Fe3+) and seawater (Yellow sea, China). In addition, the resulted lignin-based aerogels also presented a promising application in the electricity generation field. This work opens a new avenue to design liquid metals with excellent light absorption ability for the effective solar steam generation, sewage depuration and desalination, with the application of liquid metals in the electricity generation field.

Development of a PbLi heat exchanger for EU DEMO fusion reactor: Experimental test and system code assessment

In the framework of the DEMO Work Package Balance of Plant of EUROfusion consortium, ENEA has been involved in experimental and numerical activities related to the development of a prototypical heat exchanger, suitable as steam generator for the lithium-lead loop of the Dual Coolant Lithium Lead and Water Cooled Lithium Lead breeding blankets. For this purpose, an experimental campaign has been executed on the pool-type liquid metal-cooled facility CIRCE at ENEA Brasimone Research Centre.A dedicated test section named HERO has been designed and installed inside the main vessel of CIRCE. The innovative steam generator consists of a tube bundle with seven double walled bayonet tubes, fed with pressurized water. The selected configuration improves the plant safety, reducing the possibility of water-lead/lead-alloy interaction thanks to a double physical separation and allowing an easier control of eventual leakages from the coolant by pressurizing the separation region with inert gas.A set of tests has been defined to demonstrate technological feasibility and performances of this prototypical steam generator, as well as the suitability of the component for the lithium-lead loop in DEMO. In particular, one of the performed tests is presented and discussed in this paper. The experiment is characterized by a secondary loop feedwater working pressure of 10 MPa and a steam generator inlet temperature of 300 °C. On the primary side, the lead-bismuth eutectic has been used as working fluid with a steam generator inlet temperature of 480 °C. During the test, an experimental sensitivity analysis on the primary coolant mass flow rate has been performed. Furthermore, the results of a post-test analysis realized with two versions of the system thermal-hydraulic code RELAP5 are presented, in order to evaluate their capability in simulating the performances of the component and to support the validation process of the codes for heavy liquid metal applications. The work is concluded presenting a scaling analysis to find the equivalence between LBE and PbLi, recalculating the available experimental data with RELAP5 code using PbLi as working fluid.

Recent Development in Liquid Metal Materials.

Liquid metals (LM) have shown a very broad development prospect over the past decades. This review article focuses on the latest research dedicated to liquid metal materials and their applications in five significant areas: stretchable conductive composite, intelligent sensing electronic skin, catalysis, 3D printing material, and driving machines. The fabrication, specific properties and application of stretchable liquid metal‐polymer composites that can be used as self‐healing materials have been summarized. Liquid metal deposition printing technology, liquid phase 3D printing, suspension 3D printing technology, micro‐contact printing technology, and in vivo 3D printing molding technology have also been reviewed. Furthermore, the application of liquid metal catalyst in aldehyde reaction, photocatalysis, and electrocatalysis have been discussed. We have shown that electricity, magnetism, sound, light and heat could stimulate the movement of liquid metal. Through this comprehensive overview of the latest research, the main practical application, development, and mechanism of liquid metal were summarized and described. The future development of liquid metal technology was prospected, thus providing a strong basic research support for the further development of LM materials and their applications.

Unsteady development of Marangoni convection in a sidewall moving open cavity

In this study, simultaneous effect of free, forced and Marangoni convection on fluid flow and heat transfer in a sidewall moving open cavity is investigated. The cavity is filled with low Prandtl number fluid (Pr = 0.054); such a situation can be find in the application of liquid metal and semiconductor melts. Free convection is induced due to the heating of fluid from the bottom of the cavity. Forced convection is originated due to the translation of the sidewalls either in upward or downward direction. Whereas, the Marangoni convection is generated in the upper portion of the fluid due to imposed temperature gradient along the top free surface. The transient phenomena of the combined effects are analyzed numerically in dimensionless forms utilizing an in-house CFD code. The analyses are conducted under different pertinent parameters such as Marangoni number, Biot number, Reynolds number and Richardson number. The study is conducted to explore the flow-field structures and heat transfer characteristics in the presence of three convection modes with their relative strengths.

Study on the Performance of Liquid Metal Lubricated V-Groove Bearing Considering Turbulence

To study the application of liquid metal (LM) in the field of practical lubrication, the viscosity of gallium based liquid metal (GBLM) was measured initially, and the relationship between viscosity and temperature was fitted to obtain the viscosity under high temperature. Under the simulated high temperature and vacuum working environment of computed tomography tube (CTT) machines, considering the influence of turbulence, the changes, with eccentricity, of bearing capacity, discharge, friction power consumption, temperature rise, stiffness, and critical mass of the GBLM lubricated V-groove bearing (V-g B) were analyzed. Due to the special structure of V-g B, the coordinate transformation was carried out and the turbulent Reynolds equation was solved by using the finite difference method and the local integral method. The bearing film thickness and pressure distribution under the two coordinate systems were analyzed and compared and the pressure distribution of V-g B under small eccentricity and large eccentricity was studied, respectively. The performance of GBLM lubricated V-g B was studied, which provides theoretical guidance and an analytical method for LM bearing of high-performance CT equipment.

A Review of the Surface Modifications for Corrosion Mitigation of Steels in Lead and LBE

The review paper starts with the applications of liquid metals and then concentrates on lead and lead–bismuth eutectic used in Gen IV nuclear reactors and accelerator-driven systems. Key points of degradation modes of austenitic stainless steels and ferritic-martensitic steels, candidates for the structural components, are briefly summarized. Corrosion and liquid metal embrittlement are critical issues that must be overcome. Next, the paper focuses on the strong efforts paid to the mitigation of corrosion and reviews the different solutions proposed for the protection of steels in lead and lead–bismuth eutectic. There exist promising solutions based on protection by deposition of protective coatings or protection by “natural” oxidation resulting from optimized chemical composition of the steels. However, the solutions have to be confirmed especially by longer-term experiments and by additional mechanical testing.

Application of liquid metal to soft actuators and its performance evaluation

Application of liquid metal to soft actuators and its performance evaluation

Preparation and application of gallium-based conductive materials in the very recent years

Gallium and its alloys are a group of metallic materials with low-melting points at or around room temperature. Apart from the good electrical conductivity, the unique liquid state endows those metals with excellent compliance and self-healing capacity, which present great value in the development of flexible and stretchable electronics. Constrained by the high surface tension and low viscosity, however, liquid metals cannot be applied to some common microelectronics manufacturing technologies such as micro-electro mechanics in the preceding years, which impedes their mass production in electronic devices. To address these issues and broaden the applications of liquid metals in electronics devices, numerous efforts have been taken and great progress has been made especially in the very recent years. This review summaries the recent development of liquid metal-based conductive materials from the aspects of preparation or modification methods and their accommodative fabrication techniques in flexible electronic applications. Further outlook including expectations and challenges of liquid metal-based conductive materials are also presented.

Liquid metal slingshot

This Rapid Communication presents the self-propelled and controllable motion of liquid metal droplets, which is driven by surface tension and does not depend on any external force field. Its motion speed and direction can be controlled just as a projectile fired by a slingshot: The liquid metal droplet is the projectile, and a substrate surface serves as the bowstring. This motion provides a potential mechanism for the application of liquid metals in soft robotics, drug delivery, chip cooling, and other fields.Received 11 March 2020Accepted 16 October 2020DOI:https://doi.org/10.1103/PhysRevFluids.5.111601©2020 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasDrop & bubble phenomenaSurface tension effectsPhysical SystemsLiquid metalsLiquid-liquid interfacesFluid DynamicsCondensed Matter, Materials & Applied PhysicsBiological Physics

Liquid Metals in Catalysis for Energy Applications

Summary To keep up with the fast-paced transitioning of the global energy sector, which is constantly thriving to enable reliable, economic, and sustainable energy production, catalysis research has been required to continuously evolve in response. The challenges in the existing systems are predominantly due to dependencies on heterogeneous solid catalysts that are susceptible to coking. In this respect, liquid-metal (LM) catalysts have been demonstrated to have a critical advantage over conventional catalysts. Recently, LMs acquired a place in catalysis, with a reputation often synonymous with interesting properties and a remarkable ability to break trade-offs between homogeneous and heterogeneous catalysis. This review bridges the fundamental principles of LM research and the recent advances in LM-based thermal and electrochemical catalysis for energy applications. Moreover, emerging approaches for the improved utilization of LMs are outlined, and the concepts requiring greater research attention that could enable the development of exciting energy solutions are highlighted.

Progress in heat transfer research for high-temperature solar thermal applications

High-temperature solar thermal energy systems make use of concentrated solar radiation to generate electricity, produce chemical fuels, and drive energy-intensive processing of materials. Heat transfer analyses are essential for system design and optimisation. This article reviews the progress, challenges and opportunities in heat transfer research as applied to high-temperature solar thermal and thermochemical energy systems. The topics discussed include fundamentals of concentrated solar energy collection, convective heat transfer in solar receivers, application of liquid metals as heat transfer media, and heat transfer in non-reacting and reacting two-phase solid–gas systems such as particle–gas flows and gas-saturated porous structures.

Liquid Metal Motor

As an emerging soft material, liquid metal has demonstrated enormous potential for developing high performance functional devices and machines. However, current liquid metal enabled machines suffer from several issues, such as the requirement of a liquid environment, generation of weak actuating forces, and insufficient maneuverability. These restrictions limit the application of liquid metal in constructing more complex, flexible and powerful actuating systems. Here, a motor is developed based on the electrical actuation of liquid metal droplets without the need for conventional electromagnets. The approach is distinguished by (1) the encapsulation of electrolyte and multiple liquid metal droplets within an enclosed system, and (2) the creation of stable and continuous torque outside a liquid environment. In addition, an electrical brush is introduced to contact liquid metal with solid electrodes and operate the motor with low friction. The parameters affecting the actuation behavior are further investigated. Moreover, the versatility and maneuverability of the motor is demonstrated by applying it to drive untethered vehicles and boats. The unique driving mechanism endows the liquid metal motor with several advantages, including low friction, no sparking, low noise, versatile working environment, and being built from soft materials that could offer new opportunities for developing soft robotics.

A Simple and Cost-Effective Method for Producing Stable Surfactant-Coated EGaIn Liquid Metal Nanodroplets.

Liquid metals show unparalleled advantages in printable circuits, flexible wear, drug carriers, and electromagnetic shielding. However, the efficient and large-scale preparation of liquid metal nanodroplets (LM NDs) remains a significant challenge. Here, we propose a simple and efficient method for the large-scale preparation of stable eutectic gallium indium nanodroplets (EGaIn NDs). We compared different preparation methods and found that droplets with smaller particle sizes could quickly be produced using a shaking technique. The size of EGaIn NDs produced using this technique can reach 200 nm in 30 min and 100 nm in 240 min. Benefiting from the simple method, various surfactants can directly modify the surface of the EGaIn NDs to stabilize the prepared droplets. In addition, we discovered that shaking in an ice bath produced spherical nanodroplets, and after shaking for 30 min in a non-ice bath, rod-shaped gallium oxide hydroxide (GaOOH) appeared. Furthermore, the EGaIn NDs we produced have excellent stability—after storage at room temperature for 30 days, the particle size and morphology change little. The excellent stability of the produced EGaIn NDs provides a wider application of liquid metals in the fields of drug delivery, electromagnetic shielding, conductive inks, printed circuits, etc.

Perspective on liquid metal enabled space science and technology

With the rapid development of deep space exploration and commercial flight, a series of tough scientific and technological challenges were raised, which urgently require ever advanced technologies to tackle with. Recently, liquid metals, as a kind of newly emerging functional material, are attracting various attention and many breakthroughs have been made on earth. Such a scientific trend also suggests promising approaches for solving those extreme challenges in space environment. To fulfill the increasing needs thus involved, this article is dedicated to systematically introducing liquid metal material and its related disciplines into space science and technology. Firstly, existing application of liquid metal cooling for space nuclear power was summarized. Then, some potential space practices were tentatively put forward, such as liquid metal thermal interface medium, liquid metal phase change material, liquid metal convection cooling, metal alloy thermal storage, liquid metal electromagnetic shielding and liquid metal electronic printing. Fundamental as well as practical issues that would differ with earth were interpreted. Finally, potential liquid metal space experiments were proposed to investigate the liquid metal hydrodynamic characteristic, wettability and phase change mechanism in space physical environment. Overall, liquid metal enabled space science and technology investigation will not only help efficiently solve the current and future space technological problems, but also aid to stimulate the advancement of liquid metal space material science.

Study on the nucleating agents for gallium to reduce its supercooling

Gallium, a typical room temperature liquid metal, has high thermal conductivity and large volume fusion enthalpy. These characteristics make it a promising phase change material (PCM). However, the significant supercooling of gallium has obstructed its wide application. Adding nucleating agents is a commonly adopted method to reduce supercooling, while the study of nucleating agents for liquid metal is rarely reported so far. In this paper, the influences of the thermal history and the particle size of nucleating agents on the supercooling of gallium were systematically investigated. After that, several particles, such as TeO2, CaO, MgO, iron, and copper were selected as nucleating agents for experiments. The lattice constant was found as one of the most important parameters when selecting nucleating agents. In addition, a more favorable wettability of the nucleating agents with gallium also contributed to the restraint of supercooling. The experimental result showed that the addition of TeO2, whose lattice constant appears as the most similar to that of α-Ga, had the best effect for reducing the supercooling of gallium. The largest reduction of supercooling occurred when 0.5 wt.% TeO2 was added, and more additions resulted in particle agglomeration and a lower nucleation effect. This paper provides important routes for the selection of nucleating agents for gallium, which will benefit for future applications of liquid metal in building heat storage, thermal comfort maintenance and thermal management.