Lock-in Thermographie an elektrokeramischen Vielschichtbauteilen

In this Thesis, a thermo-graphical method which will allow the localisation of a heat source in electro ceramic multilayer components (due to their thermal behaviour) will be developed. Since only surface temperatures can be detected, one can only get images of the heat sources which are often located inside the specimens. To get also information about the depth of the heat source one has to use lock-in thermography. For this purpose a specimen is electrically stimulated with a periodic signal and the thermal response on the surface is detected. From the phase shift of stimulation and response, the depth under the surface can be estimated. The experimental challenge is in the miniaturised size of the specimens (approx. 1 mm), in the accuracy of the preparation and in the micro measurement with relatively fast signal times. For the thermo-graphical shots a microscope lens has to be used, so that a local resolution of approx. 15 m can be achieved. With this method it is possible to localise areas of interest that can subsequently subjected to other analyses.