FLiNaK

FLiNaK is the name of the ternary eutectic alkaline metal fluoride salt mixture LiF-NaF-KF (46.5-11.5-42 mol %).

It is used as electrolyte for the electroplating of refractory metals and compounds like titanium, tantalum, hafnium, zirconium and their borides.

FLiNaK salt was researched heavily during the late 1950s by Oak Ridge National Laboratory as potential candidate for a coolant in the molten salt reactor because of its low melting point, its high heat capacity, and its chemical stability at high temperatures.

[5] FLiNaK still gathers interest as an intermediate coolant for a high-temperature molten salt reactor where it could transfer heat without being in the presence of the fuel.

As FLiNaK melts, all three components are alkali fluorides and therefore disassociate into positive and negative ions.

FLiNaK in solid form, located inside of a glove box. Note: FLiNaK is almost pure white when crystallized, the black specks and waves in this image are likely from graphite or SiC from the crucible used to melt the salt.
Molten FLiNaK salt in a test tube heated by a natural gas flame.