A method for ultrasonic non-destructive measurement of wear-resistant coating thickness and elastic modulus

Abstract

The invention provides an ultrasonic non-destructive abrasion-resistant coating thickness and elastic modulus measuring method, which belongs to the technical field of ultrasonic non-destructive detection. The method is based on a pulse echo technology and uses a single immersion focusing probe to acquire an echo signal of an abrasion-resistant coating / metal matrix specimen once to effectively extract longitudinal wave and transverse wave signals of back and forth interfaces of the coating. Spectral analysis is carried out on longitudinal wave and transverse wave signals to acquire corresponding ultrasonic reflection coefficient amplitude spectrum (URCAS). A cross-correlation analysis two-parameter inversion technology is combined to measure the longitudinal wave sound velocity V2l and the thickness d of the coating at the same time. Through the inversion of the thickness d and the resonant frequency fnt of shear wave URCAS, the transverse wave sound velocity V2t of the coating is calculated. Density rho2 is corrected through the combination with the coating porosity counted by a metallographic method. According to an elastic modulus expression, the elastic modulus is measured. According to the method, complicated operation of conventional ultrasonic multi-probe combination or multi-angle incidence is overcome; the shortcoming that the poisson ratio is assumed to be fixed by a surface wave method is overcome; and the problem of ultrasonic quantitative measurement of the elastic modulus of the coating is solved.

Description

technical field [0001] The invention relates to a method for ultrasonically nondestructively measuring the thickness and elastic modulus of a wear-resistant coating, which belongs to the technical field of ultrasonic nondestructively testing. Background technique [0002] A1 2 o 3 , WC and other coatings have high hardness, strength, elasticity and thermal conductivity, and have extremely high wear resistance and erosion resistance, so they have become one of the focuses of wear-resistant coating technology research in recent years. Houdková et al. pointed out that for small-sized workpieces, especially in the inner cavity of the workpiece, since the spraying at a vertical angle cannot be achieved, the overall properties of the coating microstructure, thickness, and elasticity will be unsatisfactory. W.Tillmann and P.Chivavibul also pointed out that the change of spraying process (grain size, spraying angle, etc.) will affect the thickness, hardness, elasticity and bonding...

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