Supercooling - kareikyaku (English spelling)

Japanese: 過冷却 - かれいきゃく（英語表記）supercooling

This is the phenomenon in which no phase transition occurs when a substance is cooled past the transition temperature, and is also simply called supercooling. This is the phenomenon in which vapor remains gaseous even when its temperature drops below the dew point, or when a liquid does not solidify even when it is cooled below its freezing point.

Generally, this occurs when the rate at which a stable phase is generated and grows at low temperatures is slower than the cooling rate of the system. Supercooling is a metastable state, and if a stable phase material is added as a nucleus or if vibration is applied, it immediately transitions to a stable state. A liquid in a supercooled state is called a supercooled liquid. If the temperature is lowered further, the viscosity gradually increases and some materials transition to a glassy state.

[Toshihisa Yoshida]

weather

Supercooled water is unstable, and if even a single particle of frost gets mixed in, the whole thing will freeze instantly. Cloud particles in the atmosphere do not freeze until temperatures reach -40°C, and often remain as supercooled water droplets.

[Hiroo Misaki]

"Understanding the Solidification of Metals" by Eisuke Niyama (1998, Maruzen) " "Physical Properties of Glass and Supercooled Liquids: Seeking the Intersection of Theory and Experiment" edited by Osamu Yamamuro (2002, High Energy Accelerator Research Organization)

[Reference] | Glassy state | Metastable equilibrium | Phase transition

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

物質を冷却したとき転移温度を過ぎても相の転移がみられない現象をいい、単に過冷ともいう。蒸気の温度が下がって露点以下になっても気体のままであったり、液体が冷却されて凝固点以下になっても固化しないような現象である。

　一般に低温側で安定な相が生成、成長する速度が、系の冷却速度よりも遅いときにおこる。過冷却は準安定状態で、安定な相の物質を核として添加したり、振動を与えると、ただちに安定な状態に転移する。過冷却状態の液体を過冷液体という。温度をさらに下げると、しだいに粘度が大きくなりガラス状態に転移するものもある。

［吉田俊久］