In-plane Thermal Diffusivity Measurement of Thin Samples Using a Transient Fin Model and Infrared Thermography

A method for determining the in-plane thermal diffusivity of planar samples was constructed. The time-dependent temperature field of the sample heated at one edge was measured with an infrared camera. The temperature fields were averaged for different times over a narrow strip around the center line of the sample, and the temperature profiles for varying time were fitted by a solution to a corresponding one-dimensional heat equation. Heat losses by convective and radiative heat transfer were both included in the model. Two fitting parameters, the thermal diffusivity and the effective heat-loss term, were obtained from time-dependent temperature data by optimization. The ratio of these two parameters was also extracted from the steady-state temperature profile. The method was found to give good and consistent results when tested on copper and aluminum samples.