A novel ECT probe for non destructive testing on conductive materials

The development of Eddy Current non-destructive techniques and instruments is moving towards new challenges in detecting buried and smaller defects and minimizing the amplitude of excitation currents. The smaller the size of the detected defect, the greater the diagnostic capability of these techniques. Moreover, the lower the excitation current required, the longer the battery discharge time of the portable instruments, the greater the possibility of implementing broadband excitation strategies with reliable results. This feature is also important when portable instruments with array of probes have to operate for a large amount of time. To this aim, the paper proposes the assembling of a probe specifically developed to optimize the detection of small and buried defects by using reduced amplitudes of the excitation current. The proposed probe adopts a double coil excitation and a GMR based sensing section. The experimental analysis, carried out with different excitation currents amplitude on specimen with cracks having different depths and heights, have demonstrated the appreciable performance of the proposed solution.