Cryogenics

Article By:

Daney, David E. Retired, Los Alamos National Laboratory, Los Alamos, New Mexico.

Last reviewed:September 2019

DOI:https://doi.org/10.1036/1097-8542.169900

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• Cryogenics, published January 2014:Download PDF Get Adobe Acrobat Reader

The science and technology of phenomena and processes at low temperatures, defined generally and arbitrarily as below 150°C (123 K or −238°F). Numerous novel and interesting phenomena occur at cryogenic temperatures. These include liquefaction (Fig. 1) and solidification of ambient gases (Table 1); loss of ductility and embrittlement of some structural materials such as carbon steel; increase in the thermal conductivity to a maximum value, followed by a decrease as the temperature is lowered further, of relatively pure metals, ionic compounds, and crystalline dielectrics (diamond, sapphire, solidified gases, and so forth); decrease in the thermal conductivity of metal alloys and plastics; decrease in the electrical resistance of relatively pure metals; decrease in the heat capacity of solids; decrease in thermal noise and disorder of matter; and appearance of quantum effects such as superconductivity and superfluidity. See also: Electrical resistivity; Specific heat of solids; Superconductivity; Superfluidity; Temperature; Thermal conduction in solids

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