1、Designation: D 6944 03Standard Test Method forResistance of Cured Coatings to Thermal Cycling1This standard is issued under the fixed designation D 6944; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method determines the resistance of curedcoatings to repeated thermal cycles. This procedure is designedto assess the influe
3、nce of thermal cycling on adhesion and otherproperties of coatings. This procedure is not intended toprovide a quantitative measure of the service life that can beexpected from a specific coating system on a given substrate.1.2 This standard does not purport to address all of thesafety concerns, if
4、any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 660 Test Method for Evaluating Degree of Checki
5、ng ofExterior Paints2D 661 Test Method for Evaluating Degree of Cracking ofExterior Paints2D 714 Test Method for Evaluating Degree of Blistering ofPaints2D 3359 Test Methods for Measuring Adhesion by TapeTest2D 4541 Test Method for Pull-Off Strength of CoatingsUsing Portable Adhesion Testers3D 6677
6、Test Method for Evaluating Adhesion by Knife3G 147 Practice of Conditioning and Handling of Nonmetal-lic Materials for Natural and Artificial Weathering Tests43. Summary of Test Methods3.1 Test Method ACured test specimens are subjected to30 thermal cycles of immersion, freezing and heating.3.2 Test
7、 Method BCured test specimens are subjected to30 thermal cycles of freezing and heating.4. Significance and Use4.1 The purpose of this test is to obtain information on theability of a coating system to adhere to substrates underthermal stress. It is assumed that the coating systems used areapplied a
8、nd cured according to the given specifications of thecoating manufacturer.TEST METHOD AFREEZE/THAW/IMMERSION5. Apparatus5.1 Thermal Cycling Apparatus:5.1.1 The thermal cycling apparatus shall consist of asuitable chamber or chambers in which the test specimens mayundergo the specified cycle. Ideally
9、, a chamber which containsheating and refrigeration equipment and immersion capabilitiesin the same unit should be used. This chamber shall have theability to maintain continuous reproducible cycles within thespecified temperature requirements. In the event that an appa-ratus having freezing, heatin
10、g, and immersion capabilities isnot available, separate equipment for freezing, heating andimmersion may be used.5.1.2 The chamber or chambers shall have the ability tomaintain a constant temperature during each of the respectivetemperature intervals as specified by the procedure.5.1.3 The samples s
11、hall be arranged to minimize contactwith the chamber surfaces or any mounting racks, and tomaximize air flow.5.1.4 The temperature of the thermal cycling apparatus shallgive uniform readings at various locations within the chamber,within 3C (5F) at any given time, except during the transitionbetween
12、 heating and freezing cycles. A two hour temperatureramping period is permitted for the equipment to reach the nexttemperature setting.6. Test Specimens6.1 Apply each coating onto the substrate as agreed upon.Minimum film thicknesses should take substrate profile intoaccount when applied.1This test
13、method is 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 July 10, 2003. Published August 2003.2Annual Book of ASTM Standards, Vol
14、06.01.3Annual Book of ASTM Standards, Vol 06.02.4Annual Book of ASTM Standards, Vol 14.04.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 Apply each coating or coating system to a minimum oftwo specimens to determine repeatabilit
15、y. If the substrate ofchoice is concrete, then suitable encapsulation of the substratemust occur as agreed upon between purchaser and supplier.6.2.1 When destructive tests are run, it is recommended thata sufficient number of file specimens be retained so that theproperty of interest can be determin
16、ed on unexposed filespecimens each time exposed materials are evaluated.6.2.2 Exposure of a similar material of known performance(a control) at the same time as the test materials is stronglyrecommended.6.3 Follow the procedures described in Practice G 147 foridentification, conditioning and handlin
17、g of specimens of test,control, and reference materials prior to, during, and afterexposure.6.4 Unless otherwise specified, cure each test specimen fora minimum of 7 days at 23 6 3C (73 6 5F) before beginningthermal cycling.6.5 Prior to beginning the thermal cycling, determine rel-evant properties o
18、f the coating on a reference panel. TestMethods D 660, D 661, D 714, D 3359, and/or D 4541, and/orD 6677 are recommended. Consider product use requirementswhen selecting appropriate methods.7. Procedure7.1 After the curing period, place the specimens into the testchamber and begin the cycling proced
19、ure.7.1.1 A suitable procedure is shown in the table below.Other procedures as agreed upon between purchaser andsupplier may also be used.7.1.2 Thermal Cycling Procedure:Condition Time (h)-5 6 3C (23 6 5F) in air 1650 6 3C (122 6 5F) in air 425 6 3C (77 6 5F) tap water immersion 47.2 Repeat this cyc
20、le of freeze/thaw/immersion for 30cycles, or other agreed upon number of cycles. Leave thesurface of the panels wet when transferring from the immersionto the freeze cycle. Keep panels in the freeze condition uponinterruptions in the agreed upon cycle. Evaluate specimenseither every 5 cycles or at t
21、he end of 30 cycles.TEST METHOD BFREEZE/THAW8. Apparatus8.1 Thermal Cycling Apparatus:8.1.1 The thermal cycling apparatus shall consist of asuitable chamber or chambers in which the test specimens mayundergo the specified cycle. Ideally, a chamber which containsheating and refrigeration in the same
22、unit should be used. Thischamber shall have the ability to maintain continuous repro-ducible cycles within the specified temperature requirements.In the event that an apparatus having freezing and heatingcapabilities is not available, separate equipment, one chamberfor freezing and another for heati
23、ng may be used.8.1.2 The chamber or chambers shall have the ability tomaintain a constant temperature during each of the respectivetemperature intervals as specified by the procedure.8.1.3 The samples shall be arranged to minimize contactwith the chamber surfaces or any mounting racks, and tomaximiz
24、e air flow.8.1.4 The temperature of the thermal cycling apparatus shallgive uniform readings at various locations within the chamber,within 3C (5F) at any given time, except during the transitionbetween freezing and heating.Atwo hour temperature rampingperiod is permitted for the equipment to reach
25、the nexttemperature setting.8.2 Reproducibility of test results between laboratories hasbeen shown to be good when the stability of materials isevaluated in terms of performance ranking compared to othermaterials or to a control. Therefore, exposure of a similarmaterial of known performance (a contr
26、ol) at the same time asthe test materials is strongly recommended.9. Test Specimens9.1 Test specimens shall be as described in Section 6.10. Procedure10.1 After the curing period, place the specimens into thetest chamber and begin the cycling procedure.10.1.1 A suitable procedure is shown in the tab
27、le below.Other procedures as agreed upon between purchaser andsupplier may also be used.10.1.2 Thermal Cycling Procedure:Condition Time (h)-5 6 3C (23 6 5F) in air 1650 6 3C (122 6 5F) in air 810.2 Repeat this cycle of freeze/thaw for 30 cycles, or otheragreed upon number of cycles. Keep panels in t
28、he freezecondition upon interruptions in the agreed upon cycle. Evaluatespecimens either every 5 cycles or at the end of 30 cycles.11. Report11.1 Test Method used and testing cycle(s).11.2 Visual evaluation of each panel for the degree ofchecking of exterior paints as described in Test Method D 660.
29、11.3 Visual evaluation of each panel for the degree ofcracking of exterior paints as described in Test Method D 661.11.4 Visual evaluation of each panel for the degree ofblistering of exterior paints as described in Test Method D 714.11.5 Results of adhesion testing from one or more of TestMethods D
30、 3359, D 4541, and D 6677.11.6 Identification of test specimens, including substrate,surface preparation, type and thickness of coating, and cureconditions.12. Precision and Bias12.1 The precision and bias are dependent upon the specificevaluations performed after the test cycles for each givencoati
31、ng system and is therefore beyond the scope of this testmethod.13. Keywords13.1 freeze/thaw; freezing; heating; immersion; thawing;thermal cycling; thermal stressD6944032ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin
32、 this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and mus
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34、responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D6944033
