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A thermal diffusivity study of the solid phase of porous samples

A method for determination of the thermal diffusivity of the solid phase of porous samples, based on frequency-dependent scattering of optically induced thermal waves, is presented. The surface temperature variation of powder-metallurgic Fe samples, due to modulated laser heating, was detected by a photoacoustic cell in the frequency range 30-320 Hz. The thermal diffusivity values obtained from comparison with a theoretical model (Appl. Phys. A 54 6 (1992)) are close to those of a homogeneous sample.