Determination of the Thermal Diffusivity of Materials by a Nondestructive Express Method with the Use of Step-By-Step Local Heating of the Surface and High-Speed Thermography

Abstract

We propose an express method for measuring the thermal diffusivity of the materials of products that does not require cutting out of the samples of special shapes from the homogeneous mass of the product. The method is based on the local heating of the surface by step-function pulses, e.g., by a focused laser beam with simultaneous high-speed thermography performed with the help of a thermal imager. The subsequent processing of a radially symmetric picture of isotherms carried out by using an original software program makes it possible to find the thermal diffusivity of macrohomogeneous materials with an error lower than 10%. As an example, we present the results of measurements of the thermal diffusivity of the ZrO₂:MgO ceramics, PhenoCure Powder composite based on phenol formaldehyde resin, and TPK-5PD polymeric-rubber material.