NaK
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Duckysmokton
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{{for|other meanings|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 is 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.<ref>{{cite web | title=BASF Corporation – Sodium-Potassium Alloy (NaK) | url=http://www.basf.com/inorganics/pdfs/tech_datasheet/NaK.pdf | accessmonthday=September 13 | accessyear=2006 }}</ref>
==Usage==
===As coolant===
One notable use is as the [[coolant]] in experimental [[Fast neutron reactor|fast neutron nuclear reactor]]s. 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 [[Outer space|space]]. Some of the coolant has leaked and these NaK droplets constitute a significant [[space debris]] hazard.{{Fact|date=December 2007}}
===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 [[desiccant]]s 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.
==References==
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[[Category:Fusible alloys]]
[[Category:Coolants]]
[[Category:Potassium]]
[[Category:Sodium]]
[[Category:desiccants]]
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[[ja:ナトリウムカリウム合金]]
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[[zh:钠钾合金]]