Non-contact Measurements of Thermal Diffusivity using High-speed Infrared Camera

We carried out non-contact measurements of thermal diffusivity in air using the Angström method with an infrared camera, specifically for small samples to which temperature sensors could not be attached. Thermal diffusivities of an alumina plate, a skutterudite plate, a glass fiber, and a silk fiber were measured, and the effects of heat loss on the measurements were investigated. In the analysis, a model assuming constant heat transfer coefficient to the air was employed, and the validity of the method was confirmed by comparing the measured values with reported data. The limitations of the constant heat transfer coefficient model under unsteady state conditions were also clarified. For obtaining thermal diffusivity in air simply, the present model with heat loss was found to be sufficient, and the necessity of performing measurements under vacuum could be quantitatively evaluated.