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

Abstract

Liquid metals are a class of materials with a millennia-long history, albeit until 200 years ago, mostly centered on mercurybased applications. The knowledge of mercury's toxicity and the discovery of it's bioaccumulation and biomagnification in the late 20 th century resulted in phasing out mercury for copious application. Lead-based, bismuth-based, and sodiumbased technology has partially replaced mercury, but due to toxicity or reactivity issues, replacements for lead and sodium are sought. The discovery of indium and, especially, gallium has allowed for the third generation of alloys with a melting point close to room temperature. This review gives a comprehensive overview of the technological developments of fusible and liquid metals, i. e., metals and alloys with melting points below ca. 250 °C, from the early days to current research and industrial application. Special emphasis is focused on important steppingstones and recent developments of gallium-based alloys as well as how they could be used for future applications.

GaOOH Crystallite Growth on Liquid Metal Microdroplets in Water: Influence of the Local Environment

“…Metals and alloys with low melting temperatures, so-called fusible metals, and liquid metals have been known for several millennia; i.e., mercury has been known for around 4000 years, and humankind was fascinated with this liquid metal. During the millennia, a host of applications in industry and research were established for these fusible metals (i.e., for bending hollow metal tubes, thermal management systems (coolants), dental reconstruction, solders, casts, and liquid metals (in the past mostly mercury), for instance, for thermometers, barometers, pumps, and lamps).…”

“…Perhaps the most used liquid metal family to date is the Ga-based alloy family, in particular, Ga ( T m ≈ 29.6 °C), eutectic GaIn (denoted as EGaIn, T m ≈ 15.5 °C), and the eutectic composition of Ga, In, and Sn called galinstan ( T m ≈ 10.5 °C) . Gallium and its alloys have been used for several years as a substitute for mercury in medical thermometers . As an expansion liquid in thermometers, it features improved thermal stability compared to mercury- or alcohol-filled ones .…”

Redox reactions with and at liquid metals

“…Quecksilberist wohl dasbekannteste Flüssigmetall,jedochist es in derS chulew egen dessen Giftigkeit obsolet. Neben Quecksilbergibtesweitere Flüssigmetalle [2,3],z.B.die hochreaktive LegierungN atrium-Kalium( NaK, T m = À11 8C) und Gallium( T m = 29,7 8C) undd essenL egierungen,z .B.e utekti-schesG allium-Indium (EGaIn,T m % 15 8C) unde utektisches Gallium-Indium-Zinn( EGaInSn,a uchG alinstan genannt, T m % 10,5 8C).D iese Flüssigmetalles indj edocha uchw eitu nter derS chmelztemperatur wegenU nterkühlungv on ca. 30 -508Cnochflüssig undkçnnendaher beiniedrigeren Te mperaturenv erwendetw erden.…”

“…Vora llem Galliumu nd dessen Legierungenw erdeni nd er Forschung, Lehre, Entwicklung undf üre ineR eihe vonA nwendungen untersucht [2,4,5]. In Thermometerh at Galinstand as Quecksilbers eite iniger Zeit erfolgreiche rsetzt [3]. Auch fürd as Experiment "das pulsie-rendeQ uecksilberherz"w urdev on derG ruppeu mW alter Jansen [6 -8]v orgeschlagen,Q uecksilber durchG alinstan zu ersetzen.I nteressant istG alinstan,d ae sm ehrere erwünschte Eigenschaftenvereint,wie flüssiger Zustandb ei Raumtemperaturm it einerV iskositätv on ca.2 mPa•s( Wasser:c a.…”

“…Quecksilber ist wohl das bekannteste Flüssigmetall, jedoch ist es in der Schule wegen dessen Giftigkeit obsolet. Neben Quecksilber gibt es weitere Flüssigmetalle [2, 3], z. B. die hochreaktive Legierung Natrium‐Kalium (NaK, T m =−11 °C) und Gallium (T m =29,7 °C) und dessen Legierungen, z.…”