Thermal conductivity is a measure of a material's ability to conduct heat. It is the rate at which heat energy is transferred through a material per unit of temperature difference.
Generally, thermal conductivity increases with temperature for metals and decreases with temperature for non-metals. This is because as temperature increases, the atoms in metals vibrate more and can transfer heat more efficiently, while non-metals have increased phonon scattering at higher temperatures, reducing their ability to conduct heat.
The atomic structure, composition, density, and temperature of a material all play a role in determining its thermal conductivity. Additionally, impurities, defects, and microstructure can also impact thermal conductivity.
Thermal conductivity is typically measured using a device called a thermal conductivity meter. This instrument measures the temperature difference across a material and the heat flow through it, and then calculates the thermal conductivity using the material's dimensions and properties.
Thermal conductivity is important in many fields, including engineering, materials science, and thermodynamics. It is used in the design of heat exchangers, insulation materials, and electronic devices, as well as in the study of heat transfer and energy efficiency.