Detection of Defects Using GMR and Inductive Probes

Abstract

Eddy current testing (ECT) is one of the most extensively used non-destructive techniques for inspecting electrically conductive materials at very high speeds that does not require any contact between the test piece and the sensor. However, the characterization of a crack is not easy to obtain, and for this purpose, other eddy current evaluation methods are still under investigation. This work introduce a new eddy current testing technique for surface on near surface defect detection in nonmagnetic metals using giant magnetoresistive (GMR) sensors. It is shown that GMR-based eddy-current probes are more sensitive than the Inductive probes to determinate the cracks dimensions that were machined on aluminum plates.