ASTM D6677-07(2012)

Standard Test Method for Evaluating Adhesion by Knife

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 and a 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 D2197, D3359, D4541, and D7234.  
4.3 The Performance Evaluation Scale (see 7.4, Table 1) is based on both the degree of difficulty to remove the coating from the substrate and the size of removed coating.TABLE 1 Rating System    
Rating  
Description  
10  
Coating is extremely difficult to remove; fragments no larger than approximately 0.8 by 0.8 mm (1/32 in. by 1/32 in.) removed with great difficulty.  
8  
Coating is difficult to remove; chips ranging from approximately 1.6 by 1.6 mm (1/16 by 1/16 in.) to 3.2 by 3.2 mm (1/8 by 1/8 in.) can be removed with difficulty.  
6  
Coating is somewhat difficult to remove; chips ranging from approximately 3.2 by 3.2 mm (1/8 by 1/8 in.) to 6.3 by 6.3 mm (1/4 by 1/4 in.) can be removed with slight difficulty.  
4  
Coating is somewhat difficult to remove; chips in excess of 6.3 by 6.3 mm (1/4 by 1/4 in.) can be removed by exerting light pressure with the knife blade.  
2  
Coating is easily removed; once started with the knife blade, the coating can be grasped with ones fingers and easily peeled to a length of at least 6.3 mm (1/4 in.).  
0  
Coating can be easily peeled from the substrate to a length greater than 6.3 mm (1/4 in.).  
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 c...
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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Oct-2012
• ICS: 19.040 - Environmental testing
• ICS: 25.220.01 - Surface treatment and coating in general
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.46 - Industrial Protective Coatings

Relations

• Replaces: ASTM D6677-07 - Standard Test Method for Evaluating Adhesion by Knife
• Effective Date: 01-Nov-2012
• Referred By: ASTM G210-13(2023) - Standard Practice for Operating the Severe Wastewater Analysis Testing Apparatus
• Effective Date: 01-Nov-2012
• Referred By: ASTM D5163-16(2021) - Standard Guide for Establishing a Program for Condition Assessment of Coating Service Level I Coating Systems in Nuclear Power Plants
• Effective Date: 01-Nov-2012
• Referred By: ASTM D6943-15(2019) - Standard Practice for Immersion Testing of Industrial Protective Coatings and Linings
• Effective Date: 01-Nov-2012
• Referred By: ASTM D5367-16(2021) - Standard Practice for Evaluating Coatings Applied Over Surfaces Treated With Inhibitors Used to Prevent Flash Rusting of Steel When Water or Water/Abrasive Blasted
• Effective Date: 01-Nov-2012
• Referred By: ASTM D5065-17(2021) - Standard Guide for Assessing the Condition of Aged Coatings on Steel Surfaces
• Effective Date: 01-Nov-2012
• Referred By: ASTM D7230-06(2021) - Standard Guide for Evaluating Polymeric Lining Systems for Water Immersion in Coating Service Level III Safety-Related Applications on Metal Substrates
• Effective Date: 01-Nov-2012
• Referred By: ASTM D7167-12(2018) - Standard Guide for Establishing Procedures to Monitor the Performance of Safety-Related Coating Service Level III Lining Systems in an Operating Nuclear Power Plant
• Effective Date: 01-Nov-2012
• Referred By: ASTM D6237-19 - Standard Guide for Painting Inspectors (Concrete and Masonry Substrates)
• Effective Date: 01-Nov-2012
• Referred By: ASTM D3276-21 - Standard Guide for Painting Inspectors (Metal Substrates)
• Effective Date: 01-Nov-2012
• Referred By: ASTM D6944-15(2020) - Standard Practice for Determining the Resistance of Cured Coatings to Thermal Cycling
• Effective Date: 01-Nov-2012
• Referred By: ASTM D5064-16a(2021) - Standard Practice for Conducting a Patch Test to Assess Coating Compatibility
• Effective Date: 01-Nov-2012
• Referred By: ASTM D4619-12(2018) - Standard Practice for Inspection of Linings in Operating Flue Gas Desulfurization Systems
• Effective Date: 01-Nov-2012
• Referred By: ASTM D6577-15(2019) - Standard Guide for Testing Industrial Protective Coatings
• Effective Date: 01-Nov-2012
• Referred By: ASTM D5498-12a(2018) - Standard Guide for Developing a Training Program for Personnel Performing Coating and Lining Work Inspection for Nuclear Facilities
• Effective Date: 01-Nov-2012

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6677 − 07 (Reapproved 2012)
Standard Test Method for
Evaluating Adhesion by Knife
This standard is issued under the fixed designation D6677; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Significance and Use
1.1 This test method covers the procedure for assessing the 4.1 Coatings, to perform satisfactorily, must adhere to the
adhesion of coating films to substrate by using a knife. substrates on which they are applied.This test method has been
found useful as a simple means of assessing the adhesion of
1.2 This test method is used to establish whether the
coatings.Although this method is a qualitative and a subjective
adhesion of a coating to a substrate or to another coating (in
test it has been used in industry for many years and can provide
multi-coat systems) is at a generally adequate level.
valuable information.
NOTE 1—The term “substrate” relates to the basic surface on which a
4.2 Other adhesion test methods may be useful in obtaining
coating adheres (may be steel, concrete, etc. or other coating).
quantitative results. See D2197, D3359, D4541, and D7234.
1.3 This method can be used in the laboratory and field.
4.3 The Performance Evaluation Scale (see 7.4, Table 1)is
1.4 The values stated in SI units are to be regarded as the
based on both the degree of difficulty to remove the coating
standard. The values given in parentheses are for information
from the substrate and the size of removed coating.
only.
4.4 This test method does not have a known correlation to
1.5 This standard does not purport to address all of the
other adhesion test methods (pull-off, tape, etc.).
safety concerns, if any, associated with its use. It is the
4.5 A coating that has a high degree of cohesive strength
responsibility of the user of this standard to establish appro-
may appear to have worse adhesion than one that is brittle and
priate safety and health practices and determine the applica-
hence fractures easily when probed.
bility of regulatory limitations prior to use.
4.6 This method is not to be used on overly thick coatings,
2. Referenced Documents
that is, those which cannot be cut to the substrate with a utility
2.1 ASTM Standards:
knife in one stroke.
D2197 Test Method for Adhesion of Organic Coatings by
Scrape Adhesion 5. Apparatus and Materials
D3359 Test Methods for Measuring Adhesion by Tape Test
5.1 Cutting Tool—Sharp utility knife.
D4541 Test Method for Pull-Off Strength of Coatings Using
5.2 Cutting Guide—Steel or other hard metal straight edge
Portable Adhesion Testers
to ensure straight cuts.
D7234 Test Method for Pull-OffAdhesion Strength of Coat-
ings on Concrete Using Portable Pull-Off Adhesion Tes-
6. Test Specimen
ters
6.1 When this test method is used in the field, the specimen
3. Summary of Test Method isthecoatedsubstrateonwhichtheadhesionistobeevaluated.
3.1 Adhesion is determined by making an “X” cut into the 6.2 For laboratory use, apply the materials to be tested to
coating film to the substrate and by lifting the coating with a panels of the composition and surface conditions on which it is
knife. Adhesion is evaluated qualitatively ona0to10 scale. desired to determine adhesion.
NOTE 2—If desired or specified, the coated test panels may be subjected
to a preliminary exposure such as water immersion, salt spray, or high
This test method is under the jurisdiction of ASTM Committee D01 on Paint
and Related Coatings, Materials, andApplications and is the direct responsibility of humidity before conducting the knife adhesion test.
Subcommittee D01.46 on Industrial Protective Coatings.
Current edition approved Nov. 1, 2012. Published November 2012. Originally 7. Procedure
approved in 2001. Last previous edition approved in 2007 as D6677 – 07. DOI:
7.1 Select an area free of blemishes and surface imperfec-
10.1520/D6677-07R12.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or tion
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