lämpöshokkia

Lämpöshokki, known in English as thermal shock, refers to the cracking or fracturing of a material due to rapid temperature changes. This phenomenon occurs when the temperature gradient within an object is too large, causing differential expansion or contraction. Different parts of the material attempt to change size at different rates, creating stresses that can exceed the material's tensile strength.

The susceptibility of a material to thermal shock depends on several properties, including its thermal expansion coefficient, thermal conductivity, and mechanical strength. Materials with high thermal expansion coefficients and low thermal conductivity are generally more prone to thermal shock. For example, ceramics, with their often brittle nature and high expansion coefficients, are particularly susceptible.

Thermal shock can manifest in various ways. In brittle materials like glass or ceramics, it often results in visible cracks or complete fragmentation. In metals, it can lead to surface cracking, reduced fatigue life, or even distortion. The effects can be immediate or develop over time through a process known as thermal fatigue.

Preventing thermal shock involves managing temperature changes. This can include slow heating and cooling rates, using materials with lower thermal expansion coefficients, or employing designs that minimize stress concentrations. In applications where rapid temperature changes are unavoidable, materials with excellent thermal shock resistance are chosen. Examples include certain types of refractory materials used in furnaces and cookware designed to withstand stovetop-to-counter transitions.