Thermal, Viscoelastic and Surface Properties of Oxidized Field’s Metal for Additive Microfabrication

Abstract

Field’s metal, a low-melting-point eutectic alloy composed of 51% In, 32.5 Bi% and 16.5% Sn by weight and with a melting temperature of 333 K, is widely used as liquid metal coolant in advanced nuclear reactors and in electro–magneto–hydrodynamic two-phase flow loops. However, its rheological and wetting properties in liquid state make this metal suitable for the formation of droplets and other structures for application in microfabrication. As with other low-melting-point metal alloys, in the presence of air, Field’s metal has an oxide film on its surface, which provides a degree of malleability and stability. In this paper, the viscoelastic properties of Field’s metal oxide skin were studied in a parallel-plate rheometer, while surface tension and solidification and contact angles were determined using drop shape analysis techniques.

A Short History of Fusible Metals and Alloys – Towards Room Temperature Liquid Metals

“…The name Field's metal (better Field's alloy) is a pun related to the Fields medal (a prestigious price for mathematicians) [99] . It is interesting to note that little is known of this alloy besides its low melting temperature [76,100] and a few other basic physical properties. Only recently, thermophysical properties of this alloy have been put forward, [76,100] fueled by its potential application as a heat transfer medium and cooling agent in nuclear power plants as well as low melting point and heat‐free solders [101] .…”

“…It is interesting to note that little is known of this alloy besides its low melting temperature [76,100] and a few other basic physical properties. Only recently, thermophysical properties of this alloy have been put forward, [76,100] fueled by its potential application as a heat transfer medium and cooling agent in nuclear power plants as well as low melting point and heat‐free solders [101] . Nowadays, common uses of Indium are in transparent touch screens as a thin layer of ITO (indium tin oxide) that function as electrodes (coatings), [102] solders and alloys (see Section 2.4.3), electrical components, and research, as shown in the end use statistics of Indium depicted in the Figure 9b [103] .…”

Field’s Metal Nanodroplets for Creating Phase-Change Materials

“…Sub-50-nm Field’s metal nanodroplets are produced by a shear-emulsification-driven synthesis approach. While the emulsion-driven synthesis of metal nanoparticles is well-established, , the high surface tension associated with liquid metals (the surface tension of the Field’s metal is 417 mN m –1 ) and the tendency of droplets to minimize surface energy usually prevents liquid metals from forming nanometer-sized droplets through shearing methods . Therefore, the unanticipated formation of nanodroplets in the lower end of the nanometer-scale range (sub 50 nm) through low-energy mechanical agitation indicates that other mechanisms play a central role in the generation of nanodroplets.…”

The Effect of Trace Oxygen Addition on the Interface Behavior of Low-Alloy Steel

“…According to Brooks, only around 50 ppm of oxygen can reduce the surface tension of pure iron by 50% [16]. In the case of more complex systems, i.e., binary, ternary, quaternary systems, and Fe-based alloys, oxygen also affects the surface tension, lowering it [10,[17][18][19][20][21][22]. It is also worth noting that for polycomponent steels, the interface wetting is challenging to simulate, and therefore accurate data are obtained mostly experimentally [10].…”