Volume 34, Issue 5 (September 2006)
Evaluation of Adhesive Strength of Thin Plasma Sprayed Oxide Coatings by a Crosshatch Testing Method
A test method for the evaluation of the adhesive strength of coatings of thickness less than 250 µms has been attempted on coupons of pure alumina and alumina-13 wt% titania samples plasma sprayed on low alloy steel substrates. Crosshatches were made with a diamond tipped wheel with 0.02-mm width and 20-mm bore diameter, which was mounted on a common tooling and grinding machine. Cuts with 5×5 mm were made on the as-sprayed surface; subsequently, a pressure-sensitive tape was applied on the hatched surface and pulled off. The area of the coatings thus removed was interpreted in accordance with ASTM D 3359B testing standard; the testing method seems to be appropriate for qualitative evaluations.