

Thermal Conductivity and Thermal Diffusivity

Thermal conductivity is a local material property and expresses the relationship between a local temperature gradient and the resulting heat flow density:

In steady-state processes, i.e. at temporally constant temperatures, thermal conductivity is the decisive measurand to quantitatively determine heat flow.

Thermal diffusity describes the velocity of heat transfer and is defined by the quotient of thermal conductivity as the product of specific heat capacity and material density: