Scanning Acoustic Microscopy: Principle and Application in Material Testing of Antique and Contemporary Samples

Scanning acoustic microscopy (SAM) has proved to be an essential tool in materials science. Ultrasonic waves between 10 MHz and 2 GHz can be used for imaging boundary structures and elastic-mechanical discontinuities within opaque materials, compounds, or biological tissues[1, 2]. It has become an instrument for the development of IC ’s and microsensors. The lateral resolution on the surface of the specimen can vary with higher frequency, from several pm to 400 nm, while the penetrating depth is reduced from millimeters down to 10 microns in the inner region of a metallic specimen[3]. Here, an introduction to SAM and its special imaging processes is given[4, 5]. Four applications are shown, which are well suited to reveal the inner structures of the specimen.