Thermal diffusivity measurements of carbon materials using optical beam deflection

Abstract Optical beam deflection (OBD) is a non-contact, non-destructive method of evaluation of materials. It is a powerful tool for the thermal characterization of carbon materials, regardless of the morphology, geometry, thickness and the anisotropy of the sample. The theory of determining the thermal diffusivity of materials by OBD is summarized in detail. The efficacy of using OBD to measure thermal diffusivities is experimentally verified by a study of metallic samples. Finally, the ability of OBD to distinguish anisotropic chemical vapor deposition (CVD) carbon from isotropic CVD carbon is demonstrated by measuring the thermal diffusivities of samples as they are heat treated at a series of temperatures reaching beyond the graphitization temperature.