from the conferences organized by TANGER Ltd.
Active thermography is a method for nondestructive inspection of materials. This contribution presents quantitative inspection of coating thickness by flash-pulse thermographic inspection and apparent thermal effusivity based evaluation. The apparent thermal effusivity algorithm for evaluation and visualisation of coating thickness is presented. The algorithm is based on a threshold value of the apparent effusivity, which can be found for any couple of substrate and coating if their effusivities differ. The square root of time at which the apparent effusivity curve reaches this threshold is then proportional to the thickness of the coating. Effectivity of the method is demonstrated by numerical model and experimental data obtained by inspection of Cr13%Fe thermally sprayed coatings made by twin wire arc spaying technology. A linear dependence between square root of apparent effusivity threshold time and couating thickness was found. Influence of the pulse length and presence of defects on the results are studied.
Keywords: Flash pulse thermography, coating thickness, apparent effusivity, thermographic inspection© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.