Characterisation of thermal property of materials by infrared thermography

An infrared thermography is used for non-contact characterisations of thermal properties of materials. In the experiment, a pulsed laser is used to excite a transient thermal source in the material, and an infrared camera system is used to record the infrared thermal images of the subsequent heat diffusion and heat loss processes. In the theory, by a solving heat conduction equation, a two-dimensional thermal distribution function produced by the pulsed laser excitation can be obtained. Then, based on the relations between both the two-dimensional thermal distribution functions extracted at any two times, the thermal diffusivities and heat loss rates of the materials can be obtained by fitting the theoretical calculations to the infrared images recorded at different times. The results indicate that this method is useful to determine the thermal diffusivity and thermal loss for industrial non-metallic materials with rough surfaces and/or inhomogeneous microstructures.