NatriumKalium

NatriumKalium, commonly referred to as NaK, is a binary alloy of sodium (Natrium) and potassium (Kalium). The most important practical composition is the eutectic around 22% sodium and 78% potassium, which melts at about -12.6°C and is liquid at room temperature. This property gives NaK a very high thermal conductivity and low viscosity, making it attractive as a heat-transfer medium in certain high-temperature applications. The alloy has a wide liquid range and a boiling point well above 800°C, depending on composition.

Production and handling of NaK require strict inert- or oil-covered environments. It is prepared by direct alloying of molten sodium and potassium under an inert atmosphere and is typically stored in sealed containers or under mineral oil to limit exposure to air.

Chemical behavior and hazards are significant. NaK is highly reactive with air and moisture, producing heat, hydrogen gas, and caustic oxides. It can ignite spontaneously in air and reacts violently with water. Because of these hazards, handling and storage are conducted with specialized equipment and protocols to prevent contact with moisture and oxygen. In the event of a fire, conventional water-based extinguishers are ineffective and can worsen the situation; dry chemical powders or Class D extinguishing agents are typically used in controlled environments.

Applications of NaK have been most prominent in nuclear engineering as a coolant or heat-transfer medium for certain liquid-metal systems and experimental devices. While it offers advantageous thermal properties, its chemical reactivity and safety requirements limit its use to tightly controlled laboratory and industrial settings.

See also: sodium-potassium pump (Na+/K+-ATPase) in biology, which relates to the physiological roles of sodium and potassium but is unrelated to the chemical NaK alloy.