Method for nondestructively measuring bonding strength of coating interface by ultrasonic body wave phase spectrum

Abstract

A method for nondestructively measuring the bonding strength of a coating interface by ultrasonic body wave phase spectrum belongs to the technical field of ultrasonic nondestructive testing. The method adopts a set of ultrasonic detection system which comprises a water tank, a coating sample, an ultrasonic water immersion probe, an ultrasonic flaw detector, an XYZ three-dimensional stepping device and a computer; wherein ultrasonic body waves of the ultrasonic detection system are vertically incident to the coating sample to perform detection, aliasing signals P<r>(t) of water/coating and coating/substrate interfaces are collected, fast Fourier transform is performed on the P<r>(t) to obtain an unwrapped phase psi<0>(f), the psi<0>(f) is subjected to linear fitting to obtain a phase spectrum psi

(f), resonance frequencies f<n> and f<n+2> corresponding to adjacent odd or even zero phases of the psi

(f) are identified, phase change phi<k> caused by interface rigidity change is solved, and quantitative measurement of interface bonding strength is realized according to a theoretical relationship between the phi<k> and a rigidity coefficient K<n>. The method of the invention solvesthe problems that the operation of ultrasonic surface wave and ultrasonic microscope technical equipment is complex, the engineering application is difficult, a traditional ultrasonic bulk wave technology is easily influenced by the thickness of a coating, and the quantitative precision is low.

Description

technical field [0001] The invention relates to a method for nondestructively measuring coating interface bonding strength by ultrasonic body wave phase spectrum, which belongs to the technical field of ultrasonic nondestructive testing. Background technique [0002] Key components in aerospace, nuclear power and other fields generally use coating technology to meet their service requirements of high performance, long life, and high reliability. The harsh high temperature, high pressure, high wear and other service environments of components require high bonding strength at the coating / substrate interface. Lima et al. pointed out that the bonding strength of the coating interface is directly related to the coating failure. Ghasemi et al pointed out that thermal barrier coatings generally have residual stress and local micro-defects, and sufficient interface bonding strength between the coating and the substrate is required to avoid shedding failure. Therefore, the developm...

AI Technical Summary

Problems solved by technology

Solve the aliasing problems of the surface echo on the coating and the echo of the coating / substrate interface when a single ultrasonic body wave probe is vertically incident, and overcome the relatively expensive equipment, complicated operation, and difficulty in engineering application of ultrasonic surface wave technology and ultrasonic microscopy technology. The existing ultrasonic body wave technology is easily affected by the thickness of the coating, etc., and the quantitative accuracy is not high

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