Experimental Study on Thermal Barrier Coating Thickness Measurement of Key Component of Aero-enigine Based on Eddy-current Method

Thermal barrier coating materials can significantly improve the high temperature resistance, oxidation resistance, wear resistance and other properties of key components of aero-engines. In practical engineering applications, the thickness of the thermal barrier coating has important influence on the performance of the base material. The multi-frequency and multi-parameter eddy current method is used to measure the thickness of the thermal barrier coating, and an elastic eddy current thickness probe is developed. The thickness of the thermal barrier coating was retrieved with two optimal excitation frequencies. In order to verify the measurement accuracy of the multi-frequency and multi-parameter eddy current method, the coating thickness was observed using a scanning electron microscope, and the coating thicknesses obtained by the two measurements were compared and analyzed. The results show that the relative errors of the adhesive layer and the ceramic layer are within 15% and 10%, respectively, which are in the industrial allowable range. Therefore, the multi-frequency and multi-parameter eddy current method can effectively measure the thickness of the thermal barrier coating material.