A novel film eddy current probe having a detection coil interleaved to the excitation coil and the amplified effect by ferromagnetic amorphous alloys particles

Abstract

This paper presents the development of a square-film eddy current (EC) probe with a detection coil interleaved to the excitation coil to detect cracks on the surface of aluminum. The probe with an interleaved design between the detection coil and the excitation coil can eliminates the distance between the test piece surface and both coils and improves the signal-to-noise ratio. Furthermore, iron-based ferromagnetic amorphous alloy particles (FAAP) without conductivity placed above the probe to increase the magnetic flux density and enhance the ECs induced on the surface of the test piece. Moreover, FAAP also increases the interlinkage magnetic flux to the detection coil. A finite element simulation was conducted for the film EC probe to confirm the advantages of FAAP. Furthermore, experiments with probes were conducted using an aluminum plate with artificial cracks. In addition, the measurement results were analyzed to confirm the enhancement of the crack-detection ability of the FAAP. • A film probe with a detection coil interleaved to the excitation coil to detect was proposed. • The amorphous magnetic alloy particles was installed above the film eddy current probe. • The amorphous magnetic alloy particles enhanced the eddy current induced on the test piece. • The signal amplitudes significantly increased by the amorphous magnetic alloy particles.