Thermal diffusivity determination of solids by time-domain photoacoustic piezoelectric technique

Thermal–physical property is one of the most important properties of materials. The conventional frequency-domain photoacoustic piezoelectric (PAPE) technique has been developed as an important method for thermal diffusivity determination. In this paper, the PAPE technique is extended to time domain (TD). First, based on a simplified thermoelastic model, the TD PAPE theory under square-wave-modulated excitation was developed, the dependence of the TD PAPE signal on modulation frequency as well as material parameters was obtained, and the determination of thermal diffusivity was simulated and theoretically analyzed. Second, the experimental system and the corresponding measurement method were established. Third, thermal diffusivities of various standard samples, such as copper, aluminum, and nickel, were measured, and the effectiveness of the technique was verified. The results show that the TD PAPE technique can provide a simple, fast and effective way for thermal diffusion study.