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Measuring Peel Adhesion of Coatings.

pdf icon Measuring Peel Adhesion of Coatings. (545 K)
McKnight, M. E.; Seiler, J. F., Jr.; Nguyen, T.; Rossiter, W. J., Jr.

Journal of Protective Coatings and Linings, Vol. 12, No. 5, 82-89, May 1995.


adhesion; building technology; peel test; coatings


An essential requirement of protective coatings is that they adhere to the substrate to which they are applied. This is an obvious requirement, but it is a difficult one to measure quantitatively. Many procedures are available for assessing coating adhesion, including ASTM D 3359 for peel, ASTM D 4541 and ISO 4642 for tensile, and a reported procedure for shear. However, all of the procedures have limitations. For example, the D 3359 peel test is qualitative, while the tensile and shear tests require gluing a loading fixture to the surface of the coating. None of the procedures is particularly suitable for determining adhesion of coatings exposed to a wet environment. This article describes a quantitative, repeatable procedure for measuring peel adhesion that was developed at the National Institute of Standards and Technology (NIST) primarily to measure the adhesion of coatings to a steel substrate exposed to a wet environment. Two examples of its application are presented. These examples are measurements of the wet adhesion strength of powder coatings to steel and the dry adhesion strength of water-borne coatings to steel.