Analysis of thermal diffusivity of metals using lock-in thermography

The thermal diffusivity, sigma, is determined for sheets of different metals by means of an approach based on lock-in thermography in combination with periodical laser heating. Different lock-in frequencies are used to obtain the frequency dependent phase behavior of thermal waves generated by laser pulses. A subsequent curve fitting provides the coefficients required to determine the thermal diffusivity. To evaluate the effect of ambient conditions, the measurements are also performed in vacuum. A comparison with literature data substantiates that lock-in infrared thermography is a promising approach for the determination of the thermal diffusivity