EVALUATION OF ADHESION BETWEEN ADHESIVE COATING AND STEEL SUBSTRATE BY ULTRASONIC METHOD

In the article the non-destructive method of an evaluation of adhesion between adhesive coating and steel substrate is presented. The adhesion was calculated on the basis of ultrasonic measurement of wave propagating on the border of the adhesive connection. Measurements were performed in nine deterimned points before and after application of car putty coating. In each point, 30 measurements of parameters of ultrasonic wave were conducted. The height of the pulses reflected from the bottom of the steel sheet and then from the interface between the coating and the steel substrate was controlled. The average value of the reflection coefficient was on the level around 0.5. On the basis of the reflection, the coefficients can be estimated adhesion of the coating to the substrate, expressed in MPa, which is about 3.5 to 7.5 MPa. The next step in research is to calculate reflection coefficient value for surfaces prepared in a different way and for different adhesive coatings.