Scanning electron acoustic microscopy (SEAM): A technique for the detection of contact-induced surface & sub-surface cracks

A variant of the scanning acoustic microscopy technique, scanning electron acoustic microscopy (SEAM), uses a pulsed electron beam in a conventional scanning electron microscope (SEM) to generate elastic waves near the surface of the sample. Conveniently for studies of surface damage, the contrast-generating processes are at a depth commensurate with the thickness of many thin hard ceramic coatings and the typical depths of fatigue-induced cracks in both gears and rolling element bearing systems.