ASTM D6677-18(2022)

SIGNIFICANCE AND USE 4.1 Coatings, to perform satisfactorily, must adhere to the substrates on which they are applied. This test method has been found useful as a simple means of assessing the adhesion of coatings. Although this method is a qualitative (subjective) test it has been used in industry for many years and can provide valuable information. 4.2 Other adhesion test methods may be useful in obtaining quantitative results. See Test Methods D2197, D3359, D4541, and D7234. 4.3 The Performance Evaluation Scale (see Table 1) is based on both the degree of difficulty to remove the coating from the substrate and the size of removed coating chip. 4.4 This test method does not have a known correlation to other adhesion test methods (pull-off, tape, etc.). 4.5 A coating that has a high degree of cohesive strength may appear to have worse adhesion than one that is brittle and hence fractures easily when probed. 4.6 This method is not to be used on overly thick coatings, that is, those which cannot be cut to the substrate with a utility knife in one stroke. SCOPE 1.1 This test method covers the procedure for assessing the adhesion of coating films to substrate by using a knife. 1.2 This test method is used to establish whether the adhesion of a coating to a substrate or to another coating (in multi-coat systems) is at a generally adequate level. Note 1: The term “substrate” relates to the basic surface on which a coating adheres (may be steel, concrete, etc. or other coating). 1.3 This method can be used in the laboratory and field. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.