Non-destructive testing of ceramic materials by ultrasonic methods at high frequencies

The physical and technical basis for the non-destructive testing of components made out of technical ceramics by high-frequency ultrasonic methods is described. Particular emphasis is laid on a large signal/noise ratio for defect detection. In order to attain this goal, broadband and rf-carrier excitation of ultrasonic probes suitable for this purpose were used, and a detailed comparison between the two is given. An outline of a prototype apparatus based on the results of this project is presented. Finally, the viability of photoacoustic microscopy as a complementary tool for the ndt of the surface region of technical ceramics is discussed. (IZFP