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The magnetic and compressive properties of the ternary Ni40.6Fe36.4Ti23 eutectic alloys solidified under electromagnetic levitation condition were investigated. An undercooling range from 32 to 141 K was achieved, and a ternary eutectic consisting of a fibrous Fe2Ti phase and lamellar γ-Fe(Ni) + Ni3Ti phases formed. In the ternary eutectic, the γ-Fe(Ni) and Ni3Ti phases kept cooperative growth, while the Fe2Ti phase grew either cooperatively with these two phases or sometimes independently. Theoretical calculations showed that there existed a vertical flow field and temperature gradient in the center of the levitated alloy droplet, contributing to the directional growth behavior of eutectic grain. The growth velocity of primary Ni3Ti dendrite increased by 2.4 times, while that of ternary eutectic increased by 77% as undercooling rose, and consequently, the microstructures were significantly refined. The temperature stability of coercivity and residual magnetization below ambient temperature was improved once alloy undercooling reached 128 K, ascribed to the enhancement of the exchange coupling effect between the magnetic domains inside refined grains. The fracture strain of the ternary eutectic alloy increased with undercooling because microcrack propagation was further hindered and the plastic deformation was more homogeneous. Meanwhile, the fracture was dominated by transgranular (TG) mode at an undercooling of 132 K because the bonding force of grain boundaries became stronger.

Thermophysical properties of the γ-TiAl alloy Ti-48Al-2Cr-2Ni in the liquid phase were investigated with a containerless electromagnetic processing device on board the International Space Station. Containerless processing is warranted by the high liquidus temperature T liq = 1 776 K and the high dissolution reactivity in the liquid phase. Thermophysical properties investigated include the surface tension and viscosity, density, specific heat capacity and the electrical resistivity. The experiments were supported by magnetohydrodynamic fluid flow calculations. The Ti-48Al-2Cr-2Ni alloy could be stably processed over extended times in the stable and undercooled liquid phase and exhibited an exceptional degree of undercooling before solidification. Experimental processes and thermophysical properties so obtained will be described. The experiments demonstrate the broad experimental capabilities of the electromagnetic processing facility on the International Space Station for thermophysical investigations in the liquid phase of metallic alloys not achievable by other methods.

The grasping and conveying of an object by utilizing the frictional force generated by contact are performed during various steps in the process of manufacturing industrial products. Deterioration of the surface quality due to these contacts is a problem. A noncontact way to transport steel plates using electromagnetic force has been proposed as a solution to these problems. In such applications to date, electromagnets are installed in the vertical direction. However, if the steel plate is thin and lacks sufficient flexural rigidity, it is difficult to exert enough suspension force to levitate the entire steel plate. To solve this problem, we propose an edge-supported electromagnetic levitation system suitable for flexible steel plates using electromagnets installed in the horizontal direction. In this paper, we report on levitation experiments to verify the effectiveness of the proposed system and discuss characteristics of the horizontal positioning of electromagnets and levitation suspension.

In this work, a dynamic model was established for the dephosphorization of metallurgical grade silicon by levitation refining. Particular emphasis was placed on the transport behavior of phosphorus in the liquid boundary layer, then at the melt surface and finally within the gas phase surrounding the levitated droplet. Within the melt boundary layer, and at the droplet surface, temperature was the controlling factor affecting phosphorus behavior. Within the gas phase, the controlling factors were temperature and gas velocity with temperature showing a more pronounced effect on the phosphorus mass transfer coefficient than gas velocity. The dynamic model shows that the dephosphorization of MG-Si was controlled by phosphorus diffusion within the gas phase. The values calculated from the model for the mass transfer coefficient were in good agreement with dephosphorization data obtained from levitation experiments conducted with metallurgical grade silicon. This work can provide a good foundation for application of electromagnetic levitation technology to the refining of metallurgical grade silicon.

The article presents the results of multivariate calculations for the levitation metal melting system. The research had two main goals. The first goal of the multivariate calculations was to find the relationship between the basic electrical and geometric parameters of the selected calculation model and the maximum electromagnetic buoyancy force and the maximum power dissipated in the charge. The second goal was to find quasi-optimal conditions for levitation. The choice of the model with the highest melting efficiency is very important because electromagnetic levitation is essentially a low-efficiency process. Despite the low efficiency of this method, it is worth dealing with it because is one of the few methods that allow melting and obtaining alloys of refractory reactive metals. The research was limited to the analysis of the electromagnetic field modeled three-dimensionally. From among of 245 variants considered in the article, the most promising one was selected characterized by the highest efficiency. This variant will be a starting point for further work with the use of optimization methods.

In order to evaluate the energy consumption of the superconducting magnetic levitation system with real-time control, the methods of simulation and test were used to study the AC plus DC loss of the superconducting coil. The simulation established a 2D finite element model in COMSOL, which was based on the H equations method with simple form and fast calculation speed. The test was carried out on a new type of measurement system, which adopted the electrical method with high sensitivity, simple operation and easy implementation. The results of simulation and test showed that, under normal working conditions, the levitation current in the form of AC plus DC produced a relatively small energy loss below $1mW$ per meter. This conclusion is helpful for the promotion and application of superconducting magnetic levitation control system.

Thin steel plates are widely used in various industrial products. However, because of the deterioration of surface quality and metal plating that occurs during transport, some problems exist. As a solution to these problems, a noncontact transport of steel plate using electromagnetic force has been proposed. However, side slip or the dropping of the plate may occur. Therefore, we proposed the addition of electromagnetic actuators to control the horizontal motion of levitated steel plates. In this study, we examined the change in the levitation stability during noncontact transport with the addition of positioning control in the horizontal direction or changed transport conditions. As a result, the application of a magnetic field in the horizontal direction improved the levitation stability of transported thin steel plates in different transport conditions.

Electromagnetic levitation (EML) enables the handling of samples in a containerless manner, facilitating more precise measurements or manipulation of materials. Currently, EML coil design is based on two-dimensional (2D) mathematical models combined with empirical data and experience. We propose that employing a truly 3D model enables a more accurate and rational coil design. This approach shows significant differences in magnetic field, and the resulting lift and heating properties, when comparing a 2D and a 3D coil. A 3D coil, resembling the geometry of a 2D coil, requires more current to generate the same lift. Reversing the situation, a 3D coil producing the exact same magnetic field as a 2D coil has a vastly different design. Furthermore, we show that the assumption that the magnetic field is homogeneous in the axial plane within the sample volume is invalid, even for small samples, in the upper and lower regions of the coil. Using a 3D model, we design a coil capable of levitating and melting an iridium sphere with a diameter of 6 mm.

During containerless processing, the oscillating drop method can be used to measure the surface tension and viscosity of a levitated melt. Through containerless processing, reactive melts that cannot be measured through conventional methods can be accurately measured; however, the accuracy of this method is dependent on the internal flow within the drop. While laminar flow does not redistribute the momentum of the oscillations, turbulent flow does redistribute the momentum of the flow and, as a result, dominates the damping. As a result, it is important to understand the internal flow behavior and the factors that affect the flow during these experiments. Models are used for the indirect quantification and characterization of the internal flow using the experimental parameters and material properties. In some cases, such as Cu50Zr50, the flow is laminar over the full range of the experiment. In other cases, including Al75Ni25, the sample is dominated by turbulent flow at high temperatures and applied electromagnetic fields, but upon cooling, transitions to laminar flow. Additionally, cases exist in which the flow is fully turbulent over the range of interest and valid measurements using the oscillating drop method are not possible. During the design phase of the experiment, the experimental parameters should be modeled to characterize the flow behavior and ensure a clean experiment.

The production of high-purity aluminum nanoparticles (Al-NPs) is challenging due to the highly reactive nature of Al metals. Electromagnetic levitation gas condensation (ELGC) is a promising method to produce high-purity metallic particles as it avoids the interaction between molten metal and refractory-lined, which guarantees the removal of impurities such as oxygen (O). In this research, high-purity Al-NPs were successfully fabricated via ELGC process and fully characterized. The effects of power input and gas flow rate on particle size and distribution were analyzed using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and dynamic light scattering (DLS). The results showed that the Al-NPs have spherical morphologies with an average diameter of 17 nm and size distribution of NPs is narrow under helium (He) flow rate of 15 L/min at a constant temperature of 1683 &plusmn, 10 K. The purity of the NPs was confirmed by utilizing X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), and X-ray fluorescence (XRF). Finally, metal purity of 99.976% and 99.97% was measured by AAS and XRF analyses, respectively. Moreover, it was found that increasing gas flow rate and sample temperature results in a decrease in the particle size. The particle sizes for the Al-NPs obtained under He atmosphere were smaller than those obtained under Ar atmosphere.

When an ultrathin and flexible steel plate is to be levitated, levitation control becomes difficult because the ultrathin steel plate undergoes increased flexure. We herein propose a levitation method for an ultrathin steel plate that is bent to an extent that does not induce plastic deformation. In this study, to investigate the levitation stability of an ultrathin steel plate, we applied disturbance cancellation control in the bending levitation system. The object of electromagnetic levitation was a rectangular zinc-coated ultrathin steel plate (SS400) of length 800 mm, 600 mm, and thickness 0.19 mm. The vibrator was attached below the three frames, in which the electromagnet unit was installed so that the frames could be vibrated up and down. We conducted experiments on the levitation performance when the electromagnet was displaced by the frame vibration in the bending levitation system. The results showed that a stable levitation can be achieved even with an input of external disturbance when levitating at the optimum bending angle.

In this study, a numerical model was developed of the electromagnetic levitation system based on the actual structure and size of the levitation coil. The model was then used to investigate the effects of the induced magnetic field, the electric field, and the magnetic force on the lateral drift and irregular deformation of different sized copper droplets. In addition, several tests were conducted in order to verify the conclusions obtained from the numerical simulation analysis.

MoSiBTiC alloys are promising candidates for next-generation ultrahigh-temperature materials. However, the phase diagram of these alloys has been unknown. We have developed an ultrahigh-temperature thermal analyser based on blackbody radiation that can be used to analyse the melting and solidification of the alloy 67.5Mo–5Si–10B–8.75Ti–8.75 C (mol%). Furthermore, electromagnetic levitation (EML) was used for in-situ observation of solidification and microstructural study of the alloy. On the basis of the results, the following solidification pathway is proposed: Mo solid solution (Moss) begins to crystallize out as a primary phase at 1955 °C (2228 K) from a liquid state, which is followed by a (Moss+TiC) eutectic reaction starting at 1900 °C (2173 K). Molybdenum boride (Mo2B) phase precipitates from the liquid after the eutectic reaction; however, the Mo2B phase may react with the remaining liquid to form Moss and Mo5SiB2 (T2) as solidification proceeds. In addition, T2 also precipitates as a single phase from the liquid. The remaining liquid reaches the (Moss + T2 + TiC) ternary eutectic point at 1880 °C (2153 K), and the (Moss + T2 + Mo2C) eutectic reaction finally occurs at 1720 °C (1993 K). This completes the solidification of the MoSiBTiC alloy.

Nanostructured Ag@SiO2-Penicillin was synthesized from high-purity Ag0 NPs with a mean particle size of about 10 nm produced by electromagnetic levitation gas condensation (ELGC) method. The silver and penicillin contents of the synthesized nano-antibiotic were about 34 wt% and 2.5 wt% respectively, as determined by ICP-OES and TGA analyses. The antibacterial properties and synergistic effects of nanostructured Ag@SiO2 and Ag@SiO2–Penicillin on killing the Methicillin-susceptible S. aureus (MSSA) and Methicillin-resistant S. aureus (MRSA) bacteria were also examined. The nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Ag@SiO2-Penicillin NPs showed an outstanding antibacterial activity compared to Penicillin and Ag@SiO2 NPs. The Fractional inhibitory concentration (FIC) indexes were 0.54 and 0.52 against MSSA and MRSA bacteria respectively, illustrating the synergistic effects of Ag@SiO2-Penicillin NPs. In addition, Ag@SiO2-Penicillin NPs showed promising dose-dependent cytotoxicity effects indicating the protective effects emanating from anti-inflammatory properties of penicillin.

A Ti-Al based alloy was prepared by aluminothermic reduction of acid soluble titanium slag followed by electromagnetic levitation refining. It was observed from the XRD and microstructure analysis that the alloy after refining was mainly composed of TiAl2 phase, with Mn and Fe dissolving into Al lattice, Ti5Si3, TiAl, and other metallic compounds. With increase of the vacuum degree or refining time, the phase of the alloy changed from an Al-rich compound to a Ti-rich phase due to Al loss by evaporation. The kinetics of Al evaporation demonstrated that the rate determining step of Al evaporation was controlled by the mass transfer in the liquid metal phase. The oxygen removal showed increasing tendency with increase of vacuum degree and refining time. The removal rate of oxygen after refining at 1858 K, 400 Pa for 25 min was over 40% and the final percentage of oxygen in the alloy was 0.59 wt%. Vickers hardness of the alloy showed increasing tendency with increase of vacuum degree and refining time, while its bending strength showed decreasing tendency. These results are mainly attributed to the comprehensive effect of oxide inclusions removal and phase transition in the refining process.

In this paper, the design and characterization of a contactless electromagnetic levitation and electrostatic driven microsystem is presented, which has applications for example for large scale angle rotation micro mirrors. The proposed design can levitate a fabricated aluminum micro rotor which can incorporate a mirror and control it to rotate around the vertical axis within the range of ± 180°, which enlarges the scanning angle dramatically compared with conventional torsion micro mirrors. The rotation angle of the micro rotor is detected by the change of capacitance and controlled by the electrostatic force produced by variable capacitors. The levitation of the micro rotor is realized by utilizing electromagnetic inductions. The rotation is achieved through electrostatic forces generated by a digital controller. The hybrid system design for a micro rotor, combining magnetic and electrostatic forces is introduced. The digital control strategy is based on a PID controller with bias voltage. The detection interface circuit, which is based on frequency multiplexing, is also presented in this paper. It has been experimentally shown that the proposed design can levitate a 1.65 mm radius and 8 µm thickness aluminum micro rotor to 100 µm height with 20 MHz frequency and 0.5A p-p input current. Square and slope wave input experiments were carried out. The experimental results show that the control principal is in good agreement with the simulation models and this applies as well to the time-response performance and stability.

A major reason to conduct solidification experiments in space is that the unique conditions accessible in reduced-gravity allow investigation of fundamental questions while limiting the influence of sedimentation or buoyancy-induced convection. When processing metallic alloys using containerless electromagnetic levitation, convection may be controlled over a wide range, spanning the laminar-turbulent transition, by proper selection of facility operating conditions. By measuring key thermophysical properties such as density, viscosity, and electrical resistivity on-orbit, the specific sample being processed may be characterized and the results used to update pre-mission magnetohydrodynamic model predictions of induced stirring within the droplet. Thus, convection becomes a controlled experimental parameter that can be applied to an investigation of how stirring influences the metastable-to-stable transformation during rapid solidification of FeCrNi alloys. For these alloys, the incubation or delay time is observed to be a weak function of undercooling and a strong function of applied convection.

In this paper, the design of an electromagnetic levitation system and a technique for non-conductive silicon heating and conductive silicon levitation is described. The aim of the work is to describe the various parameters including coil design, applied power and specimen weight that govern the temperature of levitated silicon and silicon-iron alloy droplets.

W360 is a hot work tool steel produced by voestalpine BÖHLER Edelstahl GmbH & Co KG, a special steel producer located in Styria, Austria. Surface tension and density of liquid W360 were studied as a function of temperature in a non-contact, containerless fashion using the oscillating drop method inside an electromagnetic levitation setup. For both, surface tension and density, a linear model was adapted to present the temperature dependence of these measures, including values for the uncertainties of the fit parameters found. The data obtained are compared to pure iron (with 91 wt% the main component of W360), showing an overlap for the liquid density while there is a significant difference in surface tension (− 5.8 % at the melting temperature of pure iron of 1811 K).

The main advantage that attracted the attention of researchers was the lack of contact of liquid metal with refractory lining, which ensured the elimination of one of the main sources of metal contamination by such a harmful impurity, such as oxygen. This is especially important for melting refractory and highly reactive metals and semiconductors. Compared to other melting methods, which also ensured the absence of contact of liquid metal with the crucible (vacuum arc, electron beam floating zone, cold crucible, plasma, etc.), EML of metal melts has a number of significant advantages. Among all types of noncontact technologies, only EML has the functions of levitation and heating.

Electromagnetic levitation (EML) melting process is performed by adopting the finite-element method. It is a complicated field-coupled problem, which involves two-way interactions of electromagnetic, thermal, fluid flow fields as well as deformation. Oscillations of a solid titanium metal sample are studied to obtain the time for their balance positions under different electrical factors, such as frequency, current, and the number of coils turn. Droplet size of liquid titanium, which might be affected by different electrical factors, is also studied. It is shown that mathematical model adopted in this paper could be used to dynamically predict the melting process, balance time, and droplets size under the influences different electrical parameters.

Samples of INCONEL 718 were levitated and melted in a slag by the application of an electromagnetic field. The effects of temperature, time, and slag composition on the inclusion content of the samples were studied thoroughly. Samples were compared with the original alloy to study the effect of the process on inclusions. Size, shape, and chemical composition of remaining non-metallic inclusions were investigated. The samples were prepared by Standard Guide for Preparing and Evaluating Specimens for Automatic Inclusion Assessment of Steel (ASTM E 768-99) method and the results were reported by means of the Standard Test Methods for Determining the Inclusion Content of Steel (ASTM E 45-97). Results indicated that by increasing temperature and processing time, greater level of cleanliness could be achieved, and numbers and size of the remaining inclusions decreased significantly. It was also observed that increasing calcium fluoride content of the slag helped reduce inclusion content.

Electromagnetic levitation provides a containerless condition for materials processing, which is a desired technique to produce optimized microstructures and properties. In this paper, the large undercooling and rapid solidification of high-temperature Fe67.5Al22.8Nb9.7 alloy were realized by means of electromagnetic levitation method. The undercooling range from 13 to 150 K was achieved, and the microstructure consisted of Nb(Fe, Al)2 + (αFe) pseudoeutectic grains and a small amount of primary Nb(Fe, Al)2 phase. The eutectic growth velocity was measured and found to increase by nearly 4 times with enhanced undercooling. Both eutectic grain size and interlamellar spacing decreased more than 50% with the increase of undercooling. Owing to the structural refinement, the micromechanical property of eutectics in terms of Vickers microhardness was improved, whereas that of primary phase remained unchanged. The soft magnetism of the undercooled alloy was reduced according to the variation of hysteresis loops. Besides, the thermal expansion coefficient of this alloy increased by two times within the temperature range from 300 to 1573 K, and the alloy density variation was determined accordingly. Keywords: Eutectic growth, Undercooling, Electromagnetic levitation, Solidification, Applied performance

In contactless electromagnetic levitation technology, one of the main challenges is that the amount of power delivered to the load depends significantly on parameters of the transformer and therefore is very sensitive to system impedance variations. In this paper, a systematic design procedure based on virtual impedance control strategy is proposed to obtain high transfer efficiency and achieve maximum power transfer. A contactless electromagnetic levitation melting system was used to validate the proposed method. Both theoretical analysis and simulation results indicate the effectiveness of the proposed structure.

The Inconel 600 alloy was highly undercooled and its S/L interface migration during recalescence was observed in real time by using the electromagnetic levitation (EML) system. The characteristic of S/L interface migration and the dendritic growth velocity are strongly dependent on undercooling. At a small undercooling, the γ phase nucleates and grows to the undercooled melt with a sharp interface, and the corresponding microstructure appears as dendrite with strong texture. Nevertheless, once the undercooling exceeds the critical undercooling the sharp S/L interface transforms to a planar shape, which is attributed to the formation of equiaxed grain with a diffused orientation distribution. The 60° annealing twins are generated only when the undercooling is larger than 130 K, due to the obvious recrystallization and sufficient driving force. Besides, the compressive tests were performed on the bulk Inconel 600 alloy samples. The results demonstrate that the elastic modulus is affected little by the undercooling, however, the yield strength obviously increases with the enhancement of undercooling. The strengthening mechanism is mainly ascribed to the formation of sub grain boundaries and annealing twins.

10 th PAMIR International Conference Fundamental and Applied MHD, Jun 2016, Cagliari, Italy; International audience

The presented paper is focused on possibilities of research of rheological properties of liquids with use of the device based on the principle of electromagnetic levitation. The device works on the principle of damping of the levitated body vibrations by the liquid. Levitation is ensured by feedback control of the magnetic field using an optical barrier. Vibrations are excited by controlled interruptions of electromagnetic field. Thanks to this principle it is possible to investigate the liquid of non-Newtonian character, as well as liquids susceptible to clinging on spindles of rotational viscometers. The equipment was calibrated using silicate oil standards and its performance was compared with commercially used models of viscometers Anton Paar FRS1600 (viscosity range 3 mPa s–20 Pa s, precision 0.5%, temperature range 300–1600°C) and Brookfield DV-III Ultra (viscosity range 1.4 mPa s–20 Pa s, precision 1%, temperature range 100–1600°C).

Electromagnetic levitation (EML) is a contact-less, high-temperature technique which has had extensive application with respect to the investigation of both thermophysical and thermochemical properties of liquid alloy systems. The varying magnetic field generates an induced current inside the metal droplet, and interactions are created which produce both the Lorentz force that provides support against gravity and the Joule heating effect that melts the levitated specimen. Since metal droplets are opaque, transport phenomena inside the droplet cannot be visualized. To address this aspect, several numerical modeling techniques have been developed. The present work reviews the applications of EML techniques as well as the contributions that have been made by the use of mathematical modeling to improve understanding of the inherent processes which are characteristic features of the levitation system.

The rapid solidification mechanism of Ni–Zr alloys was investigated by electromagnetic levitation (EML) technique assisted with high speed videography. A systematic analysis of the competitive growth mode between the primary phase and eutectic structure was conducted for three types of alloys (hypoeutectic Ni-5 at.%Zr, eutectic Ni-8.8 at.%Zr and hypereutectic Ni-13 at.%Zr alloys), whose maximum undercoolings reached up to 260, 192 and 270 K, respectively. With the increase of undercooling, the primary (Ni) phase of hypoeutectic Ni-5 at.% Zr alloy transferred from well-defined dendrites to dendrite fragments. Zr atom was difficult to diffuse into the Ni lattice because the radius of Zr atom was larger than Ni atom. For eutectic Ni-8.8 at.% Zr alloy, the competitive nucleation and growth between primary (Ni) phase and eutectics could happen when the undercooling exceeded 18 K. The refined dendrites of primary (Ni) phase and various eutectic morphologies were observed at the undercooling of 192 K. For the hypereutectic Ni-13 at.% Zr alloy, the growth morphology transition of the primary Ni5Zr intermetallic compound from faceted to non-faceted crystals occurred if the liquid alloy achieved a high undercooling. Furthermore, the atomic scale structure of the primary phase was explored by the transmission electron microscopy (TEM), which revealed that the solid solubility and the lattice constant were consistent at various undercoolings. Moreover, the compressive performance of these three type alloys were determined for EML solidified samples. Due to the effects of undercooling and composition on microstructures, Ni-5 at.%Zr and Ni-8.8 at.%Zr alloys exhibited plastic deformation at the large strain condition, while Ni-13 at.%Zr alloy showed brittle fracture feature. The compressive strength and yield strength displayed a non-linear relationship with the rise of undercooling.

The temperature dependent viscosities of stable and undercooled liquid zirconium (Zr) have been studied by the electromagnetic levitation (EML) experiments on the International Space Station ISS together with molecular dynamics (MD) simulations. Oxygen additions of about 1.2 ± 0.5 at.% in EML experiments increases the viscosity of undercooled liquid Zr. MD simulations reveal a Vogel-Fulcher-Tammann-type temperature dependent viscosity for pure Zr in the temperature range of 1600–2700 K. The evolution of the internal energy and the nearest neighboring coordination numbers show crossovers at about 2000 K, indicating a local structural change when stable liquid Zr is cooled into undercooled liquid state. This local structural change is reflected by a slight drop of fraction of the cluster, and the nonlinear temperature dependent evolution of icosahedral-like, bcc-like and tetrahedral-like short-range order. The temperature dependent fraction of mobile atoms with high potential energy exhibits a strong anti-correlation with the temperature dependent viscosity. The decrease of these mobile atoms reduces the potential energy and increases the high-coordinated clusters with strong spatial correlations upon cooling, resulting in an increase of the local stability and viscosity of stable and undercooled liquid Zr. All results obtained here will promote the research activities of the thermophysical properties and structural evolution of metallic liquids.

Fast resistive pulse-heating techniques and electromagnetic levitation techniques are capable of determining thermophysical properties of metals in the liquid phase. These properties have become increasingly important as input data for modern numerical simulations. Among others, density is a very relevant parameter for e.g., casting modeling. Density determinations of copper and nickel in their liquid states are performed using a fast resistive pulse-heating setup and a recently build up electromagnetic levitation apparatus. Both methods use optical imaging techniques to determine thermal expansion of the specimen under investigation, but are operating at very different experimental durations. The pulse-heating setup provides a heating of the sample using it as part of an electrical discharge circuit. Heating rates of 108 K/s lead to experimental durations of about 60 µs. Temperature is determined by measuring surface radiance emitted from the sample by a pyrometer. The sample’s thermal expansion is monitored by an adapted CCD camera system. The electromagnetic levitation apparatus enables noncontact investigations of samples by levitating and heating them by an induction coil generating inhomogeneous electromagnetic fields. Temperature again is determined by a pyrometer. For thermal expansion determination, shadowgraph images are recorded with a high-speed CCD camera and evaluated with an edge detection algorithm. Thermal expansion then is calculated by averaging several 1000 frames for each temperature point. Investigations of copper and nickel in the liquid state were performed with both techniques and are compared to each other and to literature values.

Measurement of the thermophysical properties of liquid metals is challenging because of their high chemical activity and high temperatures. The electromagnetic levitation allows one to hold the electrically conductive liquid sample containerless in an inert atmosphere in thermal equilibrium while measurements on the sample can be taken in a non-contact way followed by extraction of some thermophysical properties. Yet, the electromagnetic forces within the skin layer inside the sample cause convective flow of the liquid thus disabling the data extraction. A static magnetic field imposed over a sample is known to damp the convective flow. With these ideas, an experimental set-up with a DC magnetic field directed perpendicular to the gravity vector was constructed and first experiments were performed with liquid Ni and some other materials. In most of the experiments the instability of the levitated sample during a slow variation of the DC magnetic field was observed which is reported in the present article.

Recent years, high quality thin steel plate is used for many industrial products. A production line of thin steel plate includes a transport system utilizing the friction force induced by contact. However, the deteriorates of surface quality from contact with rollers is a problem. As a solution to this problem, non-contact conveyance systems applying electromagnetic levitation technology have been proposed. From the previous study, control horizontal displacement of thin steel plate using electromagnet. Using horizontal displacement control, we confirmed improvement performance of magnetic levitation system. By using an electromagnet installed horizontally direction, a vertical force to support the steel plate and a horizontal force to suppress elastic vibration act on the steel plate. Focusing on these forces, we have proposed a magnetic levitation system for a steel plate with simultaneous horizontal positioning control and vertical non-contact support using a horizontal electromagnet. In this study, we carried out levitation experiment using magnetic levitation system. We verify levitating characteristic of thin steel plate.

Electromagnetic levitation (EML), a contactless metal melting method, can be used to produce ultra-pure metals and alloys. In the EML process, the levitation force exerted on the droplet is of paramount importance and is affected by many parameters. In this paper, the relationship between levitation force and parameters affecting the levitation process were investigated by dimensionless analysis. The general formula developed by dimensionless analysis was tested and evaluated by numerical modeling. This technique can be employed to design levitation systems for a variety of materials.

In this paper a new drip-and leakage-free method for the electromagnetic levitation melting of metallic samples with greater weights, stabilized position and free surface shape is presented. The method can be used in a melting furnace, as well as for the coreless induction valves applied for the flow rate control, e.g. in the continuous casting of molten metals.The applicability of the method was examined numerically and experimentally proved by tests conducted with different types of laboratory setups.

Pure titanium nanoparticles were synthesized by utilizing an Electromagnetic Levitation Melting Gas Condensation (ELM-GC) method. Pure bulk titanium samples were melted and evaporated by electromagnetic levitation technique in an inert gas atmosphere in a silica tube. Titanium nanoparticles were formed from ascending vapor by employing high purity argon and helium as carrier gases and cooling agents. Particle size and morphology of the produced nanoparticles were studied by Field-Emission Scanning Electron Microscopy (FE-SEM) and Dynamic Light Scattering (DLS) analysis. Results showed almost spherical nanoparticles with a narrow size distribution under both cooling atmospheres. The purity of the produced titanium nanoparticles was confirmed through powder X-ray diffraction (XRD) as well as X-ray fluorescence (XRF), and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) analysis. As to the impact of carrier gas, titanium nanoparticles synthesized under helium atmosphere had smaller particle size with narrower particle size distribution compared to those produced in argon. Average particle size of synthesized titanium nanoparticles under Ar and He atmospheres were about 42 and 31 nm, respectively.

This research focuses on studying levitating forces of droplets by utilizing a refining process known as electromagnetic levitation(EML). With the mathematical predictions, the levitating forces were described by a mathematical model in this article. Combined with theory analysis, the balancing phenomenon was also investigated in silicon-iron systems. The research found that the relationship between droplets position and levitation forces was linear. As EML system was a multi-induction, the levitating forces generation was affected by the properties of droplet, quality and size. The electromagnetic properties of the droplets were mainly the reasons for the levitation force to change from heating process before melting. EML droplet getting its melting point, electromagnetic properties of EML droplet were fixed due to the droplets absorbing latent heat. The results of this investigation will be used for vacuum electromagnetic levitation technology, and solar grade silicon samples will be prepared from relative inexpensive raw material, metallurgical grade silicon.