Tunnel-magnetoresistive-based Pulsed Eddy Current Probe for Inspection of Corrosion under Insulation

Abstract The problem of corrosion in the industrial oil and gas pipes has been one major contributors catastrophic structural failures. Among various types corrosion, under insulation (CUI) known to cause serious problems. Pulsed eddy current (PEC) non-destructive testing shown its effectiveness detecting hidden CUI. Most PEC systems have developed by using an inductive coil as their sensing device, while some use a magnetic sensor which potentially offers better resolution. A new probe design based on solid-state Tunnel magnetoresistance (TMR) is presented. TMR sensors offer higher sensitivities compared other commercially available sensors. performance evaluated ferromagnetic mild steel plates that thicknesses range 8mm 12mm at different stand-offs with thin aluminium sheet probe. represent levels, are mimic cladding real pipeline structure. results show overall mean absolute error (MAE) 0.19 mm, than our existing Hall-device-based