Thermal Diffusivity

Definition of Thermal Diffusivity

Thermal diffusivity (a with the unit mm2/s) is a material-specific property for characterizing unsteady heat conduction. This value describes how quickly a material reacts to a change in temperature.

In order to predict cooling processes or to simulate temperature fields, the thermal diffusivity must be known; it is a requisite for solving the Fourier Differential Equation for unsteady heat conduction.

An overview of the thermal conductivity and thermal diffusivity values of selected materials is shown in table 1.

Information about the thermal conductivity of further materials can be found in our posters “Thermal Properties of Elements", "Thermal Properties of Ceramics" and "Thermal Properties of Polymers”.

The thermal diffusivity can be measured by LFA.


Table 1: Thermal conductivity and thermal diffusivity values for various materials
Material Thermal Conductivity / W/(m•K) Thermal Diffusivity / mm2/s
Aluminum 237 98.8
Steel 81 22.8
Copper 399 117
Fused Silica 1.40 0.87
Gypsum 0.51 0.47
Polyethylene 0.35 0.15
Marble 2.8


Related Methods