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For instance, metals typically have high thermal conductivity and are very efficient at conducting heat, while the opposite is true for insulating materials such as mineral wool or Styrofoam. Correspondingly, materials of high thermal conductivity are widely used in heat sink applications, and materials of low thermal conductivity are used as ...
In heat transfer, the thermal conductivity of a substance, k, is an intensive property that indicates its ability to conduct heat. For most materials, the amount of heat conducted varies (usually non-linearly) with temperature. [1] Thermal conductivity is often measured with laser flash analysis. Alternative measurements are also established.
Thermal conduction is the diffusion of thermal energy (heat) within one material or between materials in contact. The higher temperature object has molecules with more kinetic energy; collisions between molecules distributes this kinetic energy until an object has the same kinetic energy throughout.
Thermal contact resistance is significant and may dominate for good heat conductors such as metals but can be neglected for poor heat conductors such as insulators. [2] Thermal contact conductance is an important factor in a variety of applications, largely because many physical systems contain a mechanical combination of two materials.
Metals are relatively good conductors of heat, which in metals is transported mainly by the conduction electrons. [25] At higher temperatures the electrons can occupy slightly higher energy levels given by Fermi–Dirac statistics. [2] [21] These have slightly higher momenta (kinetic energy) and can pass on thermal energy.
Diamond is the best natural conductor of heat; it even feels cold to the touch. Its thermal conductivity (2,200 W/m•K) is five times greater than the most conductive metal (Ag at 429); 300 times higher than the least conductive metal (Pu at 6.74); and nearly 4,000 times that of water (0.58) and 100,000 times that of air (0.0224). This high ...
The gaseous and liquid nonmetals have very low densities, melting and boiling points, and are poor conductors of heat and electricity. [20] The solid nonmetals have low densities and low mechanical strength (being either hard and brittle, or soft and crumbly), [ 21 ] and a wide range of electrical conductivity.
Mercury is a liquid, heavy, silvery-white metal. It is the only common liquid metal at ordinary temperatures, and as compared to other metals, it is a poor conductor of heat, but a fair conductor of electricity. [12] The table below is a summary of the key physical properties of the group 12 elements.