Visualization of spatial conductivity irregularities within conductive rubber sheets

In this contribution a contactless measurement method to determine the spatial conductivity distribution within a thin and electrically conductive test specimen is presented. The test specimen is made of an intrinsically conducting polymer, more precisely conductive rubber. As a consequence of the manufacturing process and the material composition the conductivity distribution within the rubber is inhomogeneous. Especially for industrial usage of the conductive rubber (e.g. as heating mats) a certain degree of homogeneity must be attained. To verify the homogeneity of the material a fast and indirect conductivity measurement method based on magnetic imaging and thermography was developed. Additionally, for comparison a measurement with a classical resistance probe was done. The measurement results showed a good agreement between the developed and the classical method. Moreover, the developed measurement method requires less time but still offers a higher spatial resolution.