1、Designation: D4541 17Standard Test Method forPull-Off Strength of Coatings Using Portable AdhesionTesters1This standard is issued under the fixed designation D4541; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers a procedure for evaluating thepull-off strength (commonly referred to as adhesion) of acoating syst
3、em from metal substrates. Pull-off strength ofcoatings from concrete is described in Test Method D7234.This test offers two test protocols. Protocol 1 (test to fracture)determines the greatest perpendicular force (in tension) that asurface area can bear before a plug of material is detached.Protocol
4、 2 (pass/fail) determines if the coated surface remainsintact at a defined load criteria. Fracture will occur along theweakest plane within the system comprised of the test fixture,glue, coating system, and substrate, and will be exposed by thefracture surface. This test method maximizes tensile str
5、ess ascompared to the shear stress applied by other methods, such asscratch or knife adhesion, and results may not be comparable.NOTE 1The procedure in this standard was developed for metalsubstrates, but may be appropriate for other rigid substrates such as plasticand wood. Factors such as loading
6、rate and flexibility of the substrate mustbe addressed by the user/specifier.NOTE 2The procedure in this standard was developed for use on flatsurfaces. Depending on the radius of the surface, the results could havegreater variability with lower values and averages.1.2 Pull-off strength measurements
7、 depend upon material,instrumentation and test parameters. Results obtained by eachtest method may give different results. Results should only beassessed for each test method and not be compared with otherinstruments. There are five instrument types, identified as TestMethods B-F. It is imperative t
8、o identify the test method usedwhen reporting results.NOTE 3Method A, which appeared in previous versions of thisstandard, has been eliminated as its main use is for testing on concretesubstrates (see Test Method D7234).1.3 This test method describes a class of apparatus known asportable pull-off ad
9、hesion testers.2They are capable of apply-ing a concentric load and counter load to a single surface sothat coatings can be tested even though only one side isaccessible. Measurements are limited by the strength of adhe-sive bonds between the loading fixture and the specimensurface or the cohesive s
10、trengths of the glue, coating layers,and substrate.1.4 This test can be destructive and spot repairs may benecessary.1.5 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsys
11、tem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establis
12、h appro-priate safety, health and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for
13、theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3D2651 Guide for Preparation of Metal Surfaces forAdhesiveBondingD3933 Guide for Preparation of Aluminum
14、Surfaces forStructural Adhesives Bonding (Phosphoric Acid Anodiz-ing)D7234 Test Method for Pull-Off Adhesion Strength of Coat-ings on Concrete Using Portable Pull-Off Adhesion Tes-tersE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method1This test method is
15、 under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.46 on Industrial Protective Coatings.Current edition approved Aug. 1, 2017. Published September 2017. Originallyapproved in 1993. Last previous
16、edition approved in 2009 as D4541 091. DOI:10.1520/D4541-17.2The term adhesion tester may be somewhat of a misnomer, but its adoption bytwo manufacturers and at least two patents indicates continued usage.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer S
17、ervice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 194
18、28-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Techn
19、ical Barriers to Trade (TBT) Committee.13. Summary of Test Method3.1 The general pull-off test is performed by securing aloading fixture (dolly, stud) normal (perpendicular) to thesurface of the coating with a glue. After the glue is cured, atesting apparatus is attached to the loading fixture and a
20、lignedto apply tension normal to the test surface. The force applied tothe loading fixture is then gradually and uniformly increasedand monitored until either the loading fixture is detached, or aspecified load value is reached and the test terminated. The twocommon uses of this test are test to fra
21、cture (Protocol 1), andpass/fail testing (Protocol 2). Test to fracture is used todetermine a maximum load that can be achieved when a plugof material is detached with the selected testing parameters.Pass/fail is used to verify the results of a testing procedure canmeet a minimum load criterion. Whe
22、n the loading fixture isdetached, the exposed surface represents the plane of limitingstrength within the system. The nature of the plane of fractureis qualified in accordance with the percent of adhesive andcohesive failures, and the actual interfaces and layers involved.The reported load is comput
23、ed based on the maximum indi-cated load, the instrument calibration data, and the originalsurface area stressed. Results obtained using different testdevices will vary because the results depend on instrumenta-tion parameters. Variations in results are also expected whentests are performed under dif
24、ferent test procedures or environ-mental conditions (see 4.2).4. Significance and Use4.1 The pull-off strength of a coating is a performanceproperty that may be referenced in specifications. This testmethod serves as a means for uniformly preparing and testingcoated surfaces, and evaluating and repo
25、rting the results. Thistest method is applicable to any portable apparatus meeting therequirements for determining the pull-off strength of a coatingin this standard (see Annexes).4.2 Variations in results with the same coating are likelywhen any parameter of the test is changed. This includeschange
26、 in glue, load fixture size, substrate coating cure time,pull rate, environmental conditions, if the coating is scored, orusing a different device. Therefore, when a series of results willbe compared with one another or used for statistical analysis,the type of apparatus, substrate, test procedures,
27、 glue type, andif scoring is used should be the same for the pulls considered.4It is recommended that these parameters and the environmentalconditions allowed during the test be mutually agreed uponbetween the interested parties.4.3 The purchaser or specifier shall designate a specific testmethod pr
28、ocedure; B, C, D, E, or F and test Protocol; 1, or 2,when calling out this standard. In cases where either theProtocol or a pass/fail criterion is not designated, Protocol 1shall be used.5. Apparatus5.1 Adhesion Tester, commercially available, or comparableapparatus to the specific examples listed i
29、n Annex A1 AnnexA5.5.1.1 Loading Fixtures, having a flat surface on one end thatcan be adhered to the coating and a means of attachment to thetester on the other end. Optimal size of the loading fixture isdetermined by the adhesion tester capabilities. The fixture andtester combination should be cho
30、sen so that the expectedmaximum pull load the coating will be subjected to during thetest is within the range of the tester.5.1.2 Detaching Assembly (adhesion tester), having a cen-tral grip for engaging the fixture.5.1.3 Base, on the detaching assembly, or an annular bearingring if needed for unifo
31、rmly pressing against the coatingsurface around the fixture either directly, or by way of anintermediate bearing ring. A means of aligning the base isneeded so that the resultant force is normal to the surface.5.1.4 Means of moving the grip away from the base to allowthe loading of the fixture in as
32、 smooth and uniform a manneras possible and so that a torsion free, co-axial (opposing pull ofthe grip and push of the base along the same axis) force resultsbetween them.5.1.5 Timer, or means of limiting the loading rate. A timer isthe minimum equipment when used by the operator along withthe force
33、 indicator in 5.1.6.5.1.6 Force Indicator and Calibration Information, fordetermining the actual force delivered to the loading fixture.5.2 Solvent, or other means for cleaning the loading fixturesurface. Finger prints, moisture, oxides, and dust tend to be theprimary contaminants.5.3 Sandpaper, or
34、other means, used to roughen the surfacesfor glue application and adherence to the coating. When usingsandpaper it is recommended to use 100 grit or finer.5.4 Gluethe material used for securing the loading fixtureto the coating. Two component epoxies and cyanoacrylates aretwo commonly used glues. Se
35、lect a glue that does not affect thecoating properties, flow through the coating or attack thecoating.5.5 Clamps, magnetic, mechanical, tape or similar, if neededfor holding the fixture in place while the glue cures.5.6 Cotton Swabs, or other means for removing excess glueand defining the adhered ar
36、ea. Any method for removingexcess glue that damages the surface, such as scoring (see 6.7),must generally be avoided since induced surface flaws maycause premature failure of the coating.5.7 Scoring Tool, circular hole cutter, or similar tool to scorethrough to the substrate around the loading fixtu
37、re.6. Test Preparation6.1 The method for selecting the coating sites to be preparedfor testing depends upon the objectives of the test andagreements between the contracting parties. There are,however, a few physical restrictions imposed by the generalmethod and apparatus. The following requirements
38、apply to allsites:4Reference to potential variability of the adhesion test has been made in variouspublications, including the assessment of variability completed for the test methodfound in ASTM Research Report RR:D01-1147.D4541 1726.1.1 The selected test area must be large enough to accom-modate t
39、he specified number of replicate tests. The surface mayhave any orientation with reference to gravitational pull. Eachloading fixture must be separated by at least the distanceneeded to accommodate the detaching apparatus. For Protocol1 or to statistically characterize a test area, three or morerepl
40、ications are required.6.1.2 The selected test areas must also have enough perpen-dicular and radial clearance to accommodate the apparatus, beflat enough to permit alignment, and be rigid enough to supportthe counter force. It should be noted that measurements closeto an edge may not be representati
41、ve of the coating as a whole.6.2 Since the rigidity of the substrate affects results of thetest and is not a controllable test variable in fieldmeasurements, some knowledge of the substrate thickness andcomposition should be reported for subsequent analysis orlaboratory comparisons. For example, ste
42、el substrate of lessthan 3.2 mm (18 in.) thickness usually reduces test resultscompared to 6.4 mm (14-in.) thick steel substrates.6.3 Subject to the requirements of 6.1, select representativetest areas and clean the surfaces in a manner that will not affectintegrity of the coating or leave a residue
43、. To reduce the risk ofglue fracture affecting the test, the surface of the coating can belightly abraded to promote adhesion of the glue to the surface.If the surface is abraded, care must be taken to preventsignificant loss of coating thickness. Clean the area to removeparticulates after abrading.
44、 Use of a solvent may be necessaryto remove all contaminants. If a solvent is required, select onethat does not compromise the integrity of the coating.6.4 Clean the loading fixture surface as indicated by theapparatus manufacturer. Failures at the fixture-glue interfacecan often be avoided by treat
45、ing the fixture surfaces inaccordance with an appropriate ASTM standard practice forpreparing metal surfaces for glue bonding.NOTE 4Guides D2651 and D3933 are typical of well-proven methodsfor improving adhesive bond strengths to metal surfaces.6.5 Prepare the glue in accordance with the glue manufa
46、c-turers recommendations. Apply the glue to the fixture or thesurface to be tested, or both, using a method and thicknessrecommended by the glue manufacturer. Be certain to apply theglue across the entire fixture surface. Position the fixture on thesurface to be tested. Carefully remove any excess g
47、lue fromaround the fixture. (WarningMovement, especially twisting,can cause tiny bubbles to coalesce into large holidays thatconstitute stress discontinuities during testing which may leadto glue fracture.)6.6 Based on the glue manufacturers recommendations andthe anticipated environmental condition
48、s, allow enough timefor the glue to cure. During the glue set and early cure stage,a constant contact pressure should be maintained on the fixture.Magnetic or mechanical clamping systems work well, butsystems relying on tack, such as masking tape, should be usedwith care to ensure that they do not r
49、elax with time and allowair to intrude between the fixture and the test area.6.7 When scoring around the test surface is agreed uponbetween the purchaser and seller, extreme care is required toprevent micro-cracking in the coating or glue, since suchcracks may cause reduced values. Scored samples constitute adifferent test procedure, and should be clearly reported with theresults. Scoring may be required for thick-film coatings,reinforced coatings and elastomeric coatings. Scoring, ifperformed, can be completed before or after the load fixture isglued to the coating. Wh
