Entwicklung eines Messverfahrens zur Bestimmung der Wärmeleitfähigkeit von plattenförmigen Proben mittels Lock-in-Thermografie

Translated title of the contribution: Measuring the thermal conductivity of disc-shaped samples using lock-in-thermography

Peter Pulm

Research output: ThesisDiploma Thesis


Many electroceramic parts have disc-shape. For being able to conduct thermal management of such parts it is necessary to know their thermal conductivity. As there is no fast and inexpensive method to measure the thermal conductivity of such parts, this master thesis tries to develop a new measurement method for this purpose. This work uses a photothermal measurement approach combined with lock-in-thermography. As a physical model thermal diffusion waves were used and expanded to consider heat losses caused by convection and disc shape of the sample. The models were digitally realized and studied. The measurement principle used goes as following: Thermal diffusion waves were induced into a disc-shaped sample by using a sinusoidally modulated heat source penetrating one surface of the sample. The opposite side of the sample was monitored by using a thermography camera. By measuring the phase lag between the arriving thermal diffusion wave and the heat source the thermal conductivity can be calculated. After the first experiments the window of application of the measurement approach could be estimated. The results showed that the developed approach can be used to measure the thermal conductivity of bariumtitanate, a ceramic widely used to produce ptc-parts for electric circuits. Hence the thermal conductivity of bariumtitanate could be measured up to 10 % accuracy. Further improvements seem possible by further experiments, applying a 3-D-model and using a heat source which can be directly digitally modulated.
Translated title of the contributionMeasuring the thermal conductivity of disc-shaped samples using lock-in-thermography
Original languageGerman
  • Supancic, Peter Hans, Supervisor (internal)
Award date8 Apr 2011
Publication statusPublished - 2011

Bibliographical note

embargoed until null


  • thermography
  • thermal conductivity
  • heat conductivity
  • lock-in
  • measurement methods
  • measuring

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