Galinstan

Galinstan is a commercial liquid metal alloy whose composition is taken from a family of eutectic alloys mainly consisting of gallium, indium, and tin. Such eutectic alloys are liquids at room temperature, typically melting at −19 °C (−2 °F). Due to the low toxicity and low reactivity of its component metals, Galinstan finds use as a replacement for many applications that previously employed the toxic liquid mercury or the reactive NaK (sodium–potassium alloy). An example of a typical eutectic composition is 68 wt% Ga, 22 wt% In and 10 wt% Sn, though it varies between 62 wt% and 95 wt% Ga, 5 wt% and 22 wt% In, 0 wt% and 16 wt% Sn, while keeping eutectic ability. The marketing name is a portmanteau of gallium, indium, and stannum (Latin for "tin"). Galinstan is a registered trademark of the German company Geratherm Medical AG. The exact composition of Galinstan is not publicly known.

Galinstan tends to wet and adhere to many materials, including glass, which limits its use compared to mercury. Galinstan is commercially used as a mercury replacement in thermometers due to its nontoxic properties, but the inner tube must be coated with gallium oxide to prevent the alloy from wetting the glass surface.

Galinstan may be used as a thermal interface for computer hardware cooling solutions, though its cost and aggressivity (it corrodes many other metals such as aluminium by dissolving them) are major obstacles for widespread use. It is also electrically conductive, and thus needs to be applied more carefully than regular insulating compounds.

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