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.