Investigation of an encircling Pulsed Eddy Current probe for corrosion detection

Pulsed Eddy Current (PEC) is an emerging nondestructive testing and evaluation (NDT & E) technique and has been used for a wide range of conductive materials. Existing Pulsed Eddy Current probes use surface type probes on pipes. For this type of probes, it is assumed that the diameter of the pipe is significantly larger than that of the excitation coil and the pipe wall is assumed as a plate. In this work, a new encircling pulsed eddy current probe is proposed. The system aims to increase the scanned area by taking advantage of an encircling coil to scan the complete circumference of a pipe with a single pulse. The proposed system consists of an encircling driver coil, Giant magnetoresistance (GMR) magnetic field sensors, a conditioning circuit, a data acquisition card connected to a computer with Matlab software for signal processing and presentation.