Experimental Evaluation of a Flexible Eddy Current Sensor Pattern to Characterize the Hardness of Burned Area in Ferromagnetic Material

摘要

Eddy Current is a powerful means of detection of defects located close to the surface in conductive parts. Defects to be detected can classically be flaws, but also variations of a mechanical or electromagnetic property of material. A typical Eddy Current pattern is composed of an emitting coil and a receiving coil. These coils can be etched on a kapton to design flexible probes able to fit complex shaped of pieces. By optimization of coil diameters and distance between coils, it is possible to obtain specific properties of the pattern. In this paper, we use a flexible pattern optimized for the detection of the variation of conductivity, thanks to a great sensitivity to this parameter and a straight response in the complex plane when it evolves. The applicability of this pattern is shown to detect and characterize burned areas of different intensities and their consequences on material hardness.