Research on eddy current testing defect identification using tunneling magnetoresistance sensor

Eddy current non-destructive testing has the advantages of non-contact, high sensitivity, and wide applicability to metal materials, and is widely used in high-pressure boilers, metal corrosion, and pipeline testing. With the rapid development of intelligent manufacturing, defect recognition has gradually evolved from the presence or absence of defects to the comprehensive recognition of size and morphology. To improve detection accuracy and efficiency, this study proposed an ECT system integrated with tunneling magnetoresistance (TMR) sensors. A dedicated magnetic field-to-voltage (B-V) calibration system was developed, and an imaging algorithm was implemented to convert defect signals in aluminum plates into two-dimensional visualizations. Experimental results demonstrate that the proposed system effectively detects and images defects with complex geometries, providing a reliable solution for defect inspection in metallic plates.