Which of the following defects can predominantly be identified using Eddy Current Testing?

Eddy Current Testing (ET) is particularly effective for identifying surface and near-surface defects in conductive materials. This method works by inducing electrical currents, known as eddy currents, within the material being tested. The presence of any defects, such as cracks, pits, or other discontinuities that occur near the surface, will disrupt the flow of these currents, leading to measurable changes in the electrical impedance of the material.

The sensitivity of ET to such surface flaws is largely due to the electromagnetic principles on which it operates, where eddy currents are confined to the skin depth of the material. Consequently, the technique is primarily used for detecting defects that may not penetrate deeply into the substrate, making it an invaluable tool in non-destructive testing for ensuring material integrity without compromising the item being inspected.

Identifying internal voids, variations in grain structure, or thickness inconsistencies in non-conductive materials like plastics presents significant challenges with ET, as these defects either may not significantly influence the eddy currents or are outside the effective range of the method. Hence, the choice highlighting surface and near-surface defects accurately reflects the strengths of Eddy Current Testing.