Eddy current testing is a non-contact electromagnetic testing technique used for the inspection of conductive materials without the need to remove non-conductive coatings. An alternating current is passed through a coil in order to create an alternating magnetic field which is used to induce a localised current (eddy current) into the material under test.
Discontinuities such as fatigue cracks will interrupt the flow of eddy currents and alter the terminal impedance of the test coil. The amplitude and phase of the received signal can be interpreted to ascertain the severity and exact location of any discontinuities found. Eddy current is routinely used to inspect a wide range of different materials and components across several fields of engineering including oil and gas, nuclear, power generation and aerospace.