Micro eddy current testing by micro magnetic sensor array

A micro Eddy Current Testing (ECT) system for planar thin specimens made of INCONEL 600 with flaws was proposed and developed. A micro ECT probe used here consists of a conventional pancake-type coil as an exciting coil and a micro magnetic sensor array as a set of pickup coils. Magnetic field perturbation due to a flaw was measured with high spatial resolution and signal-to-noise (S/N) ratio. The measured signals from the array were compared with numerical results obtained by a three-dimensional A-/spl psi/ code. It was confirmed that the micro ECT system has the potential to evaluate the length and depth of a flaw with better accuracy than that of a conventional pancake-type ECT in the steam generator tubings in a pressurized water nuclear reactor.<>