Study for the Design of Eddy Current Microsensor Arrays for Non Destructive Testing Applications

In this paper, an experimental study was carried out for the design of microsensor arrays dedicated to eddy current non destructive applications. A 3-microcoil 1-D array sensor was realized thanks to microtechnology. Since each coil can be used as a transmitter or a receiver, five different transmission- reception strategies were considered for the inspection of a nickel based alloy target, featuring several calibrated surface notches. While the most basic strategy did not detect the smallest notch (0.1 x 0.1 x 0.1 mm
³
), the best strategy detected it with a 20 dB signal to noise ratio. The detection performances were then analyzed versus frequency and versus notch size.