APPLICATION OF THERMAL-WAVE TECHNIQUES FO R CHARACTERIZATION OF CERAMICS

Application of thermal wave techniques on ceramics using photothermal and photoacoustic effects is described. Cracks and inclusions in zirco nia titanium carbide and in green as well as in sintered aluminium oxi de are detected with a lateral resolution of a few microns. Non-linear effects lean to contrast enhancement, when perpendicular cracks are d etected. Frequency dependent measurements allow to determine the depth of horizontal cracks and to measure the thickness of zirconia coating s. Delaminations of tungsten carbide coatings and thickness variations of silicon carbide coatings appear in measured images.