Characterization of surfaces and surface-near zones of solid materials by acoustical imaging techniques

Scanning Acoustic Microscopy (SAM), High-frequency Acoustic Imaging(HAIM), and Scanning Laser Acoustic Microscopy(SLAM) use the interaction of high-frequency acoustic waves with the sample material. The contrast of the acoustic images is mainly determined by the elastic properties of the object under investigation. Since acoustic waves can also penetrate opaque materials, it is possible to image internal structures of the sample, to look for defects, to evaluate homogeneity, and to gain information on elastic parameters. These properties made acoustic microscopy and high-frequency acoustics an important tool to non-destructive evaluation(NDE) and material characterization. The wide range of use for these instruments is shown on the examples of fracture mechanics, thin film measurements, evaluation of adherence, evaluation of surface conditions due to machining, wear and corrosion, defect detection.