Thermal Shock

Definition - What does Thermal Shock mean?

Thermal shock is a variation in temperature which causes tension in a material. It frequently causes breakage in the material, and is most common in brittle materials such as ceramics.

This is a process that takes place abruptly when there is a sudden variation of temperature, either from hot to cold or vice versa. It is most common in materials that are structurally weak as well as those which offer a poor heat conductivity.

Corrosionpedia explains Thermal Shock

A temperature change will always produce either an expansion or a contraction of a material. If the material has high heat conduction (such as metals) the physical change in size is rather even. If this is accompanied by a strong material resistant to tension, then thermal shock is not a likely result.

However, on materials such as ceramics, glass, rocks and others, thermal shock is probable. These materials have poor heat conduction, which causes them to heat up or cool down in an uneven manner, which in turn causes them to expand or contract differently.

Some examples of thermal shock are:

  • Ice in a hotter liquid will shatter since water (liquid or solid) is a poor heat conductor. The ice in the liquid suffers a sudden increase in temperature and expands at different rates.
  • Rocks containing ore strains near a heat source such as a bonfire will cool down unevenly when splashed with cold water. The temperature change causes the rocks to contract unevenly, which causes fracture.
  • Head gaskets in internal combustion engines might fail by cracking due to a thermal shock when encountering sudden temperature changes.

Thermal shock can be prevented by:

  • Avoiding sudden temperature changes
  • Increasing the structural strength of the material
  • Enabling the material to conduct heat more efficiently, causing a more even expansion or contraction when encountering temperature changes
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