Abstract
The adhesion of plasma sprayed coating to substrate was inspected by ultrasonic testing method. As the probe, an immersion-type probe was used. Sprayed coatings were obtained by spraying NiCr alloy powder to SS41 mild steel plates by plasma jet spraying process.
Main results obtained are summarized as follows:
1) The adhesion of sprayed coating to substrate can be inspected by ultrasonic testing method, especially by detecting bottom echo, Bc.
2) Bottom echo increases with increasing adhesion strength of coating to substrate.
3) Some image displaying methods by computer graphics, by which location and shape of peeling of coating and adhesion distribution are able to be visualized, were constructed.
4) Some parameters to evaluate the adhesion of coating (Seff/S0, Bcav/Bb, Bcmax/Bb) were proposed. Although some correlations between these ultrasonic parameters and adhesion are recognized, they had relatively large dispersion.
