Einsatz von Wärmewellenverfahren bei der Charakterisierung von Keramik

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