An acoustic microscope for surface characterization

Progress on the development of a wide-angle, focused-beam acoustic microscope is presented. In the imaging mode, the tightly focused-beam is raster-scanned over the surface while simultaneously measuring the reflected signal. The beam may be focused beneath the surface in order to image subsurface features. Thus, it is possible to detect subsurface cracking introduced by machining or interfacial voids or disbonds in coatings.