Spreading Of Liquid Metal Research Articles

Conformally Adhesive, Large-Area, Solidlike, yet Transient Liquid Metal Thin Films and Patterns via Gelatin-Regulated Droplet Deposition and Sintering.

Adhesion and spreading of liquid metals (LMs) on substrates are essential steps for the generation of flexible electronics and thermal management devices. However, the controlled deposition is limited by the high surface tension and peculiar wetting and adhesion behavior of LMs. Herein, we introduce gelatin-regulated LM droplet deposition and sintering (GLMDDS), for the upscalable production of conformally adhesive, solidlike, yet transient LM thin films and patterns on diverse substrates. This method involves four steps: homogeneous deposition of LM microdroplets, gelation of the LM-gelatin solution, toughening of the gelatin hydrogel by solvent displacement, and peeling-induced sintering of LM microdroplets. The LM thin film exhibits a three-layer structure, comprising an LM microdroplet-embedded tough organohydrogel adhesion layer, a continuous LM layer, and an oxide skin. The composite exhibits high stretchability and mechanical robustness, conformal adhesion to various substrates, high conductivity (4.35 × 105 S·m-1), and transience (86% LM recycled). Large-scale deposition (i.e., 5.6 dm2) and the potential for patterns on diverse substrates demonstrate its upscalability and broad suitability. Finally, the LM thin films and patterns are applied for flexible and wearable devices, i.e., pressure sensors, heaters, human motion tracking devices, and thermal management devices, illustrating the broad applicability of this strategy.

Electrochemically enabled manipulation of gallium-based liquid metals within porous copper

Electrochemically enabled reactive wetting, coating and spreading of liquid metals within porous copper.

Wetting and spreading of liquid metals on ZrB2-based ceramics

The possibility to exploit commercially the peculiar characteristics of refractory metallic and ceramic materials and in particular of Zirconium diboride ceramics—a class of promising materials for high temperature applications—often depends to a great extent on the ability to join different ceramics one to the other or to special metallic alloys. As the behaviour of a metal-ceramic joint is ruled by the chemical and the physical properties of the interface, the knowledge of wettability, interfacial tensions and interfacial reactions is mandatory to understand what happens at the liquid metal-ceramic interface during joining processes.

Atomic dynamics and Marangoni films during liquid-metal spreading

Despite its apparent simplicity, spreading of liquid metals at high temperatures has defied description and generalization. Wetting at high temperature is usually accompanied by interdiffusion and chemical reaction, but the forces that drive reactive spreading and the mechanisms that control its kinetics have been very poorly understood. The unsolved challenge has been to link macroscopic measurements such as the dynamic contact angle or the speed of a moving liquid front to phenomena occurring at the microscopic and even atomic level in the vicinity of the triple solid-liquid-vapour junction. We have taken a big step towards meeting this challenge. Our systematic analysis of the spreading of metal-metal systems with varying degrees of mutual solubility allows us to report on the fundamental differences between the mechanisms controlling spreading of organic liquids and liquid metals and on formation of Marangoni films driven by surface-tension gradients in high-temperature systems.

Dynamics of interparticle reactions in spherical metal powders during electric sintering

The dynamic characteristics of the process of interparticle neck formation depend not only on current density (raising the current density by 1.7 times increases interaction rates by an order) but also on the positions of the particles relative to the direction of passage of current (particles lying in a plane parallel to the direction of passage of current interact 3.4–5 times more rapidly than particles lying in a plane perpendicular to this direction). The kinetics of powder particle sintering by an electric current is due to the most intense sintering mechanisms, such as viscous flow, transport through the gaseous phase, and spreading of liquid metal over the solid surfaces of particles. The strongest influence on the kinetics of mutual particle sintering is exerted by a transport mechanism with n< 0.5. Such a mechanism may be provided by electroerosion transport in the interparticle gap.

Wetting and spreading of liquid metals: the rôle of surface composition

AbstractQuantitative measurements of the surface compositional changes which occur during the wetting of copper substrates in vacuum by liquid SnPb solder alloys have been made in situ, by Auger electron spectroscopy. Five different spatial regions associated with the wetting front have been identified. Away from the spreading front, the liquid solder shows a surface enhancement of lead. Approaching the front, adjacent bands of Cu3Sn intermetallic compound, and tin‐depleted liquid occur, both of width ∼ 20 μm. The lead‐enriched surface of the solder extends over these two regions, and out over the copper to form approximately 50% monolayer ‘halo’ of ∼ 80 μm width. Beyond the halo, in the fifth region, very small amounts of tin and lead were detected. The lead halo forms rapidly by surface diffusion, and precedes wetting. In the absence of other limitations, it is the reduction of the copper substrate surface energy by the lead halo that restricts the spread of the molten alloy. Intermetallic compound formation is relatively slow and only takes place once spreading has ceased and a quasiequilibrium reached.

Wetting and Spreading of Liquid Metals on Solid Metal Surfaces

Wetting and Spreading of Liquid Metals on Solid Metal Surfaces