ASTM B571Standard Practice for Qualitative Adhesion Testing of Metallic Coatings
This practice covers simple, qualitative tests for evaluating the adhesion of metallic coatings on various substances.
Several of the tests are limited to specific types of coatings, thickness ranges, ductilities, or compositions of the substrate. These limitations are noted generally in the test descriptions and are summarized in Table 1 for certain metallic coatings.
“Perfect” adhesion exists if the bonding between the coating and the substrate is greater than the cohesive strength of either. Such adhesion is usually obtained if good electroplating practices are followed.
For many purposes, the adhesion test has the objective of detecting any adhesion less than “perfect.” For such a test, one uses any means available to attempt to separate the coating from the substrate. This may be prying, hammering, bending, beating, heating, sawing, grinding, pulling, scribing, chiseling, or a combination of such treatments. If the coating peels, flakes, or lifts from the substrate, the adhesion is less than perfect.