Research Terms
This procedure for measuring the surface tension of molten metals or alloys utilizes electrostatic levitation and resonance to derive the values with sufficient accuracy for designing reliable metallic 3D prints. The use of 3D printing in the metals industry is growing rapidly, and analysts expect the market for metal 3D printing to be worth $10 billion by 2030. Advancements in metallic 3D printing would improve resource utilization so that unneeded tools could be melted down for 3D reprinting as other tools. Such on-site manufacturing could reduce the amount of refined metal needed for many projects, including long-term space missions. Accurate measurement of thermophysical properties like surface tension is crucial for various manufacturing methods, such as metal 3D printing and crystal growth. Traditional procedures for surface tension measurement fail when measuring high-temperature materials because of their high surface reactivity. Electrostatic levitation of liquid droplets can facilitate accurate surface tension measurement via pulse-decay analysis, but this can prove inaccurate if the droplets are highly viscous or the levitation system is noisy.
Researchers at the University of Florida and NASA have developed a system that accurately measures the surface tension of oscillating liquid droplets at high temperatures. Resonance analysis of an electrostatically levitated molten metal droplet measures its surface tension value, which enables accurate calculation of the 3D printing speed of a metal in order to eliminate aberrations in prints. This measurement system will undergo tests in microgravity, which should demonstrate its ability to determine surface tension.
Highly accurate system to measure surface tension of molten metals that can improve the quality of metallic 3D printing and crystal growth processes
The process measures the surface tension of a molten metal droplet that is electrostatically levitated in a vacuum (at least 10-7 torr). A range of continuously applied electric field oscillations causes a maximum deformation of the droplet at two distinct modes of oscillation. The droplet’s resonance then allows determination of its surface tension value at a specific temperature. The system works with high viscosity materials and remains accurate in extreme high-temperature environments . The surface tension value determines the 3D printing speed of a metal, so increased measurement accuracy can reduce or eliminate aberrations. This will improve the potential for on-site manufacturing, which would reduce the mass of metals and processing energy needed in space.
This device that uses electrostatic oscillations can measure interfacial tension between liquids in extreme environments with accuracy. Understanding interfacial tension is important for production in many industries, such as the chemical, cosmetic, and automobile industries. Available technologies can be used to determine interfacial tension only under certain conditions. Previously, samples with high melting points, high viscosities, or samples with similar densities could not be tested. Researchers at the University of Florida have developed a system and device that will overcome these obstacles and allow companies to better compare the interfacial tension of their product to a theoretical value. This will allow products to be adjusted for optimal fit for a prescribed use, such as improved semiconductor crystals that could result in better devices.
System and device for more accurate measure of interfacial tension even in extreme environments
This system and device is capable of characterizing or measuring interfacial tension between layers of liquids through the use of electrostatic oscillation. A dish with multiple liquids can be positioned between electrodes; a constant voltage superimposed with an alternating voltage is then applied across the electrodes. The amplitude of the alternating voltage can be increased to determine the amplitude at which the interface between the liquids begins to deflect or Faraday waves are created. This amplitude can characterize the interfacial tension between the liquids and be compared to the theoretical value.
This contactless, contamination-free levitation platform accurately and reliably measures the surface tension of high-temperature molten metals by analyzing droplet images at natural frequencies. In standard materials science and metallurgical practice, advanced engineers and researchers use traditional thermophysical analysis methods to calculate liquid-surface interactions. However, existing measurement media and testing experiences are often limited by high surface reactivity, poor spectral resolution, or a rapid decline in data integrity when evaluating materials at extreme temperatures. This lack of rapid kinetic efficiency and targeted selectivity reduces the effectiveness of diagnostic systems, particularly for capturing precise thermophysical phenomena under extreme, high-reactivity conditions.
The diagnostic platform, developed by researchers at the University of Florida, enables highly efficient recognition and analysis of advanced thermophysical properties through an expanded frequency sweep that operates across higher-order modal thresholds. The system offers several advantages over conventional testing matrices, including extending data capture beyond traditional thresholds to isolate data from each individual mode within a single trial, post-capture image refinement for enhanced analytical accuracy, and a highly stable architecture that supports independent, repeatable measurement cycles. By using a levitation-based approach, the platform guarantees a fully contactless testing matrix, eliminating chemical interactions and contamination risks from high-reactivity materials. These properties allow the platform to function as a versatile evaluation tool for mitigating severe manufacturing defects and ensuring process compliance across multiple industrial scales.
Researchers at the University of Florida address a growing need for advanced thermophysical measurement technologies as manufacturing and aerospace sectors globally emphasize strict quality standards, process reliability, and material structural integrity. The global aerospace 3D printing market is experiencing robust growth, propelled by newly established production methodologies and expanding municipal, industrial, and consumer applications. Valued at $4.04 billion in 2025, the aerospace 3D printing sector is projected to expand to $20.41 billion by 2034. Concurrently, the global tensiometer market, valued at $146.0 million in 2025, is projected to reach $219.4 million by 2033.
A contactless, levitation-based diagnostic platform designed to capture high-precision, contamination-free surface tension measurements of molten alloys, directly mitigating material defects and maximizing structural reliability in advanced 3D metal printing and aerospace additive manufacturing systems
Traditional methods calculate the surface tension by analyzing molten metal droplet images at natural frequencies of n = 2 and n = 3. University of Florida researchers have developed a new levitation-based method by expanding the frequency sweep to capture higher-order modes. By analyzing beyond n = 3, the system delves into data from each mode within a single trial to significantly greater detail; this allows the approach to cross-verify between trials. The surface tension value determines the 3D printing speed of a metal, so increased measurement accuracy can reduce or eliminate aberrations. This approach promises enhanced accuracy and reliability in measuring surface tension, which is ideal in industries focusing on 3D metal printing.
This heat transfer system removes heat in zero gravity through conductance using vibrations induced by an AC electrostatic force. Heat transfer in microgravity is limited in the absence of buoyancy-driven convection. The conventional heat transfer approaches on Earth utilize buoyancy-driven flow and do not work in space, particularly in closed-loop systems requiring external pumps. As high-powered electronics become smaller and more powerful, heat must dissipate. Current thermal management breaks into active or passive thermal control systems.
Active thermal control systems require power input to operate, while passive thermal control systems do not. In active systems, pumped fluid systems decrease sensitivity to pressure drops, increase flow rate control, and achieve more precise temperature control within allowable margins. However, prominent disadvantages of active systems are the associated mechanical pump, requiring an electrical input that consumes part of the spacecraft’s power budget, and the potential cavitation of pumped systems, introducing possible system failures. On the other hand, passive systems do not use mechanical pumps, lowering the risks of system failures, but have a minimum startup heat flux. Electrostatic resonance can enhance heat transfer in microgravity.
Researchers at the University of Florida have developed a heat transfer control system able to function in zero-gravity environments. It removes heat through conductance using vibrations induced by an AC electrostatic force, showcasing a substantial increase in heat flux. The dissipated heat is applicable for heating and converting to mechanical energy.
Active heat transfer system uses AC electrostatic resonance to remove heat in microgravity
This heat transfer management system composes two water baths, at the top and bottom of the device, held at a constant temperature. Between the water baths sits an aluminum electrode at the top boundary and an indium tin oxide (ITO) coated glass electrode at the bottom boundary. Both these electrodes are sapphire, an electric insulator, directing the electricity to flow through the fluids as intended. A voltage and frequency are applied across the electrodes, causing electrostatic fields to create wavelike patterns for increasing the heat flux. This device combines the reliability of active thermal management and the ability of passive thermal management to avoid cavitation and mechanical failure.
This quasi-one-dimensional microfluidic electrochemical platform suppresses convection through microscale confinement and eliminates electric field singularities by combining thin film electrodes with a dielectric overhang that shields the top surface of the electrode. This design will enable the isolation of diffusion and transport effects in electrochemical systems. Accurate measurement of intrinsic electrochemical kinetics and metal surface energies is critical for applications in energy storage, corrosion science, materials processing, and biotechnology Transport control in electrochemical cells is essential for quantifying chemical reactions at the electrode level, proving integral to technologies such as batteries, fuel cells, biosensors, and materials processing. Available electrochemical setups are often influenced by convective transport and geometric artifacts such as corner growth, making it difficult to determine true reaction kinetics and surface properties.
Researchers at the University of Florida have developed a fabrication protocol and cell architecture that minimizes these effects, allowing measurement of metal surface energies within 95% of predicted values while isolating diffusion-controlled transport. This platform can also be extended beyond copper-copper sulfate systems to other metals and provides a versatile tool for fundamental electrochemical research and materials development.
For example, the same dielectric overhang architecture can be applied to other electrochemical systems, including reversible redox couples, battery-relevant redox chemistries with stationary or slowly moving interfaces, and electrocatalytic reactions where a quasi-1D diffusion field is advantageous. In each case, the principal design adjustments involve selecting electrode and overhang materials that are electrochemically inert within the desired potential window, provide adequate adhesion to the substrate, and are chemically compatible with the lithographic etchants and electrolytes used in device fabrication and operation. These considerations enable the extension of the platform to a broad class of reactions without fundamentally altering the quasi-1D transport characteristics.
A microfluidic electrochemical cell and an electrode design isolates diffusion and transport effects, enabling the precise measurement of metal surface energies and electrochemical reaction kinetics
Researchers at the University of Florida have developed a specialized electrochemical cell design and fabrication protocol that enables controlled investigation of transport and surface phenomena. The system structures the electrode geometry and surrounding environment to suppress convective flow and limit geometric irregularities, allowing diffusion to dominate mass transport. By creating a well-defined and stable interface, the platform allows accurate measurement of electrochemical reactions and surface energies without interference from external transport effects. Unlike conventional setups, which are often influenced by fluid motion and uneven growth at electrode edges, this design isolates intrinsic material behavior. While the platform has been demonstrated with copper electrodes, there is promise that this system can work well with other metals as well, making it a versatile tool for studying electrochemical kinetics and fundamental material properties across different systems.
