Multilayer Thickness Detection Method of Thermal Barrier Coating Based on Reflective Terahertz Time-Domain Spectroscopy

Abstract

The invention discloses a thermal barrier coating multi-layer thickness detection method based on a reflective terahertz time domain spectroscopy technology. The method includes the following steps: applying a terahertz time domain spectral detection device to measure signals reflected by the air and a detected thermal barrier coating when terahertz waves pass through the air and the detected thermal barrier coating, taking the measured signals as reference signals and sample signals in a time domain, conducting Fourier transform on the reference signals, and taking the transformed reference signals as terahertz incoming radio frequency domain spectral signals; establishing a terahertz multi-layer reflection theoretical model; and continuously changing thickness values of all layers in thethermal barrier coating, substituting the values into the multi-layer reflection theoretical model, conducting inverse Fourier transform after theoretical frequency domain spectral signals are obtained, obtaining theoretical values of the signals in the time domain, comparing the signals with sample signals measure by an experiment, and adopting an optimal algorithm for optimization till a theoretical calculation result is consistent with an experiment measuring result, wherein the thickness values of all layers are results of the detected thickness. The invention can provide a new method foraccurate, non-destructive and rapid detection of the thickness of the thermal barrier coating.

Description

Technical field [0001] The invention and a method for detecting the multilayer thickness of a thermal barrier coating based on a reflection type terahertz time-domain spectroscopy technology belong to the technical field of nondestructive and rapid detection of thermal barrier coatings. Background technique [0002] The non-destructive testing and evaluation of the thickness of the thermal barrier coating has important strategic significance for the health status monitoring and life evaluation of aero-engine blades, and thus the flight safety of military aircraft. It is a key issue that needs to be solved urgently. [0003] Currently available methods for detecting and evaluating the thickness of thermal barrier coatings include metallography, electrochemical impedance spectroscopy, fluorescence spectroscopy, ultrasound, radiation, infrared, microwave, acoustic emission, eddy current, terahertz, capacitance, etc. Metallographic method is simple and intuitive, but it belongs to dest...

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Problems solved by technology

[0018] The purpose of the present invention is to provide a method for detecting the multilayer thickness of thermal barrier coatings based on reflective terahertz time-domain spectroscopy technology, which can solve the problem of poor detection accuracy of thermal barrier coating thickness at present, and overcome the measurement accuracy of traditional methods Low, need a large amount of experimental data and can only measure a single parameter, etc.

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