APPLICATION OF ULTRASONIC VELOCITY USED TO CHARACTERIZE THE PROPERTIES OF THE CERAMIC COATINGS

High-intensity pulsed ion beam (HIPIB) irradiation was performed on the plasma sprayed Cr2O3 coatings with the thickness of 50 μm and different properties of coatings have been obtained. The velocity was deduced based on the frequency interval between the minima of the reflection coefficient. The results have shown that the velocity increased from 2 002 m/s for as-sprayed coating to 2 099 and 2 197 m/s 1 and 5-shot irradiated coatings. With increasing the shot number,the enlarged splats reformed by serious splats remelting and sufficient cavities sealing induced more uniform and compact structure. The observations of SEM and microhardness agree with that of the ultrasonic analysis. The research indicated that the velocity could be used to characterize the properties of the plasma sprayed coatings irradiated by HIPIB.