THERMAL-DIFFUSIVITY MEASUREMENTS IN POROUS CERAMICS BY PHOTOTHERMAL METHODS

We present a study of the use of photothermal methods to measure the t hermal diffusivity of porous ceramic materials as an alternative to ot her conventional methods. Specifically, we discuss the use of three mo dulated techniques - thermoreflectance, IR radiometry, and the mirage effect - as complementary tools. Measurements of 'local' and 'global' thermal diffusivity are presented for a set of SiC samples of various porosities. In particular, the thermal diffusivity of three samples of SiC of different porosities is measured (by the mirage technique) as a function of temperature in the range from ambient to 1000 K.