Everything about Nak totally explained
» For other meanings, see Nak (disambiguation).
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NaK (often pronounced as such, rhyming with "sack") is an alloy of
sodium (Na) and
potassium (K), and particularly one that's liquid at room temperatures. It is a commercially available material in various grades. NaK is highly reactive with air or water, and must be handled with special precautions. Quantities as small as one gram can be a fire or explosion risk.
Physical properties
Alloys with between about 40% and 90% potassium by weight are liquid at room temperature. The mixture with the lowest melting point (the
eutectic mix), consisting of 78% potassium and 22% sodium, is liquid from −12.6 to 785 °C, and has a density of 866 kg/m³ at 21°C and 855 kg/m³ at 100°C.
Usage
As coolant
One notable use is as the
coolant in experimental
fast neutron nuclear reactors. Unlike commercial plants, these are frequently shut down and defuelled. Use of
lead or pure sodium, the other materials used in practical reactors, would require continual heating to maintain the coolant as a liquid. Use of NaK overcomes this. NaK is used in many other heat transfer applications for similar reasons.
The Soviet
RORSAT radar satellites were powered by a NaK-cooled reactor. Apart from the wide liquid temperature range, NaK has a very low
vapor pressure, important in the vacuum of
space. Some of the coolant has leaked and these NaK droplets constitute a significant
space debris hazard.
In catalysis
NaK is also used as a catalyst for many reactions, including precursors of
ibuprofen.
As desiccant
Both sodium and potassium are used as
desiccants in drying solvents prior to distillation. However, without heating, the solid metal is only able to react at the surface. Formation of oxide crusts also reduces the reactivity. As a liquid metal alloy at room temperature, the use of NaK as a
desiccant helps to avoid these problems.
Further Information
Get more info on 'Nak'.
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