Designation: D – 01Standard Test Method for Evaluating Adhesion by Knife1 This standard is issued under the fixed desig. From ASTM D Standard Test Method for Evaluating Adhesion by Knife. Section 3 | Summary of Test Method. Adhesion is determined by making an “ X”. Buy ASTM D Standard Test Method for Evaluating Adhesion by Knife from SAI Global.
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Irrespective of the application of the test, there are standard test methods procedures for conducting adhesion testing that should be followed to ensure consistency, especially when performing comparative analyses. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
ASTM D – 18 Standard Test Method for Evaluating Adhesion by Knife
Precautions are included regarding the use of the test on coatings with a high cohesive strength that may appear to have worse adhesion than one that is brittle and fractures easily. Generally, adhesion ratings of 8 and 10 are considered good, adhesion values of 4 and 6 are considered marginal, and adhesion values of 2 and 0 are considered poor.
Never the less, the adhesion is oftentimes considered to be acceptable under these conditions.
In order to be successful a coating system has to have both good tensile and shear adhesion. While tape and knife adhesion tests are generally regarded as more subjective than their tensile pull-off adhesion test counter parts, the tape and knife adhesion tests can be much more revealing d667 the true adhesion properties of a coating system. August 7, at 8: A f6677 in parentheses indicates the year of last reapproval.
It is correct this affirmation?
Standard Test Method for Evaluating Adhesion by Knife
The test has also been used successfully on softer substrates e. See DD and D A superscript epsilon indicates an xstm change since the last revision or reapproval. The shear tests are oftentimes more definitive because they better replicate the way in which coatings fail. We use cookies to understand how you use our site and to improve your experience.
Table 1 provides the evaluation criteria for Method A; Awtm 2 provides the evaluation criteria for Method B. This is primarily due to the directional forces applied to the coating system during the tests.
Coating Adhesion Testing using Knife/Tape Methods
Adhesion testing is also a valuable indicator for determining the integrity of coating systems that have been in service for extended periods of time, may require maintenance, and overcoating is a strategy being considered; and is frequently used during coating failure investigations.
If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below.
This test method has been vertex of the angle, attempt to lift up the coating from the found useful as a simple means of assessing the adhesion of substrate or from the coating below.
Tensile pull-off adhesion is the subject of an article by Melissa Swogger that is also available on the KTA University site.
Tape and knife adhesion exert a prying type of force. Compliance concerns here maybe need further investigation before final releases. In many instances a coating system can have excellent tensile adhesion but poor shear adhesion.
Test Specimen bility of regulatory limitations prior to use. Adhesion is evaluated qualitatively on a 0 to 10 scale. When appropriate, the nature and location of the separation is documented.
Further, the results of any knife adhesion tests performed on these coatings must be carefully considered. That is a correct statement. Adhesion tests that consistently reveal an adhesive break between coats or a cohesive break within a coat do not provide any information relative to the adhesion of the coating or coating system to the substrate.
Make each leg 1 of the angle a minimum of The tip of a knife blade is then inserted into the intersect of the two incisions and used to attempt to lift the coating from the substrate or an underlying coating.
The standard also contains a pictorial guide to aid in the rating of the cross-cut Method B. It is the to ensure straight cuts. The adhesion by knife test may provide a more accurate picture of the actual adhesion characteristics.
Adhesion testing may be a requirement of a coating specification, or may be used for coating system performance qualification in a laboratory. Undercutting and peeling can occur as a result of shear forces.
Tensile adhesion tests f6677 a force perpendicular to the coating system.