Use of ultrasound in connection with holographic interferometry for non-destructive testing of thermally sprayed coatings

Based on a new holographic technique ultrasound field on rough metallic surfaces are visualized. In contrast to the current method of sound detection using transducers, the ultrasound is probed by a contact free method, recording the sound field of a larger surface area simultaneously. This is of advantage in finding and estimating defects in the surface region, as the influence of the defects on the sound field can be visualized directly. (orig./RW)