Detecting the defects of warm-sprayed Ti-6Al-4V coating using Eddy current testing method

Thermal spay coatings have been widely used to provide structural components with protection from harsh environments such as corrosion, heat, and wear resistance. However, delamination, pores or peeling defects may exist in an as-fabricated coating which influence the mechanical properties of the coating. We developed an eddy current testing (ECT) system using a special ECT probe. The ECT probe was composed of one detection coil and two excitation coils. The lower excitation coil was used to produce the excitation magnetic field in the specimen and the upper excitation coil was used to compensate the background signal. In this study, the feasibility of our ECT system to inspect the Ti-6Al-4V warm spray (WS) coatings were investigated. The artificial defects embedded between the Ti-6Al-4V coating and the substrate were successfully detected using the ECT system.