Thermal properties of paint coatings on different backings using a scanning photo acoustic technique

A scanning photo acoustic technique to determine the thermal transport parameters, thermal diffusivity, effusivity and conductivity, as well as heat capacity of paint coatings on different backings is described. These parameters are obtained by measuring the normalized photo acoustic phase values from paint coatings of varying thicknesses and then fitting the experimental data with the theoretical expression for phase. Results are reported on four different black paint coatings on a metallic backing. The values obtained for thermal diffusivity are comparable to those reported in the literature following other techniques. Measurements have also been carried out on paint coatings over backings that are good as well as poor thermal conductors. No significant changes in the values of the thermal parameters of paint coatings could be detected for different backing materials with widely differing thermal properties.