INFRARED TIIERMAlrWA VE STUDIES OF COATED SURFACES

In recent years plasma-sprayed coatings and polymer coatings have found wide application in manufacturing. Although the quality of the coatings improved over the years, there is a need for reliable NDE techniques to assess the quality and test the integrity of these coatings. Most existing techniques are not suitable for real-time applications. The introduction of synchronous thermal wave video imaging techniques using infrared cameras[1, 2] has made it possible to make images of thermal wave phenomena in almost real-time. In this work we describe the application of a pulsed heating and synchronous infrared thermal wave detection technique to image sub-surface defects in plasma-sprayed thermal barrier coatings and polymer coatings on metal substrates.