Nondestructive, electrical impedance-based, thermal barrier coating inspection

摘要

A method and apparatus are provided for inspecting a coated substrate such as a multi-layer coating on a substrate of a turbine airfoil. At each of a number of locations along the airfoil a number of frequencies of alternating current are passed through the airfoil. At least one impedance parameter is measured. The measured impedance parameters are utilized to determine a condition of the coating.