CHARACTERIZATION OF PLASMA-SPRAYED COATINGS USING NDE TECHNIQUES

A round-robin test was implemented where nine European research instit ution and universities applied different thermal, ultrasonic and magne tic methods for measuring the thickness of plasma-sprayed coatings. Th e coatings, which had thicknesses ranging form 50 to 500 microns, were applied on substrates of AISI 316, a standard industrial structural m aterial, and on Armco-iron in order to have a material of known therma l properties. Destructive testing was performed after the other method s had been applied, resulting in detailed information on the coating t hickness, rugosity, and uniformity. The results obtained with the appl ied methods on the two unknown samples for each substrate type agreed within 20% with the destructive testing data.