1、Designation: D2247 11Standard Practice forTesting Water Resistance of Coatings in 100 % RelativeHumidity1This standard is issued under the fixed designation D2247; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This practice covers the basic principles a
3、nd operatingprocedures for testing water resistance of coatings by exposingcoated specimens in an atmosphere maintained at 100 %relative humidity so that condensation forms on the testspecimens.1.2 This practice uses the technique of creating a slighttemperature differential within the exposure area
4、 to formcondensation on the coated specimens. As the warmer satu-rated air passes the cooler specimens, water is deposited ontothe specimens in the form of condensation.1.3 This practice places the entire specimen in the exposurearea allowing condensation to form on all surfaces. This makesthis prac
5、tice suitable for flat panels as well as large or 3Dobjects. This practice differs from other methods where con-densation is only formed on the front coating surface, but theback surface is outside the exposure area. Other tests may alsodeposit water droplets on the surface but where the source isno
6、t from condensation.NOTE 1Alternative practices for testing the water resistance ofcoatings include Practices D870, D1735, and D4585.1.4 This practice is limited to the methods of obtaining,measuring, and controlling the conditions and procedures oftests conducted in 100 % relative humidity. It does
7、 not specifyspecimen preparation, or evaluation of results.1.5 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is ther
8、esponsibility 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:2D609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Varnish, Con
9、version Coatings, andRelated Coating ProductsD610 Practice for Evaluating Degree of Rusting on PaintedSteel SurfacesD714 Test Method for Evaluating Degree of Blistering ofPaintsD823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsD870 Practice
10、for Testing Water Resistance of CoatingsUsing Water ImmersionD1193 Specification for Reagent WaterD1654 Test Method for Evaluation of Painted or CoatedSpecimens Subjected to Corrosive EnvironmentsD1730 Practices for Preparation of Aluminum andAluminum-Alloy Surfaces for PaintingD1735 Practice for Te
11、sting Water Resistance of CoatingsUsing Water Fog ApparatusD2616 Test Method for Evaluation of Visual Color Differ-ence With a Gray ScaleD3359 Test Methods for Measuring Adhesion by Tape TestD3363 Test Method for Film Hardness by Pencil TestD4541 Test Method for Pull-Off Strength of Coatings UsingPo
12、rtable Adhesion TestersD4585 Practice for Testing Water Resistance of CoatingsUsing Controlled Condensation3. Summary of Practice3.1 Coated specimens are placed in an enclosed chambercontaining a heated, saturated mixture of air and water vapor.The temperature of the chamber is usually maintained at
13、 38C(100F). At 100 % relative humidity (RH), a very small1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.27 on Accelerated Testing.Current edition approved Feb. 1, 2011. Publi
14、shed March 2011. Originallyapproved in 1966. Last previous edition approved in 2010 as D2247 10. DOI:10.1520/D2247-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer t
15、o the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.temperature difference between the specimen and the surround-i
16、ng vapor causes the formation of condensation on the speci-mens. The exposure condition is varied by selecting theduration of the test. Water permeates the coating at rates thatare dependent upon the characteristics of the coating. Anyeffects such as color change, blistering, loss of adhesion,soften
17、ing, or embrittlement are observed and reported.4. Significance and Use4.1 Water can cause the degradation of coatings, so knowl-edge of how a coating resists water is helpful for assessing howit will perform in actual service. Failure in tests at 100 %relative humidity may be caused by a number of
18、factorsincluding a deficiency in the coating itself, contamination ofthe substrate, or inadequate surface preparation. This practiceis therefore useful for evaluating coatings alone or completecoating systems.4.2 Tests at 100 % relative humidity are used for specifica-tion acceptance, quality contro
19、l, and research and developmentfor coatings and substrate treatments. Some tests are used for apass or fail determination at an arbitrary time.Acoating systemis considered to pass if there is no evidence of water-relatedfailure after a period of time. Other tests are used to monitordegree of failure
20、 as a function of exposure time.4.2.1 Arbitrary pass/fail levels and the test durations re-quired are typically set in other material specific test methods.Users of this practice alone may use the known performance ofthe controls to set test end points.Another option is to continuethe test until all
21、 specimens have failed, and use the time toreach failure as a way to differentiate performance.4.3 Results obtained from the use of 100 % humidity tests inaccordance with this practice should not be represented asbeing equivalent to a period of exposure to water in the naturalenvironment, until the
22、degree of quantitative correlation hasbeen established for the coating or coating system.4.4 The test chamber can be a small laboratory cabinet or aroom large enough to hold an automobile or a truck. Someautomobile manufacturers test completed vehicles in roomsmaintained at 100 % relative humidity.
23、Corrosion tests can beconducted, as the condensate dripping off the test articles in notrecirculated.5. Apparatus5.1 Test Chamber, constructed of corrosion-resistant mate-rials with supports for the test specimens.5.2 Source of Heated Water Vapor can be created by one ofthe following methods:5.2.1 H
24、eated Water Tank, within the test chamber, a watersupply, and a water level control.5.2.2 Water Vapor (Steam) Generator, located outside thetest chamber, a water supply, and a means of introducing thevapor to the test chamber.5.3 Thermostatic Control, for the water heater with thesensor located adja
25、cent to the specimen holders, or a means ofcontrolling volume of steam.5.4 Thermometer, with sensor located adjacent to the speci-men holders.5.5 Diagrams and details of the apparatus are shown inAppendix X1.6. Test Specimens6.1 This practice does not cover the preparation of testspecimens. The subs
26、trate composition and surface preparation,specimen preparation, and the number of specimens should beagreed upon prior to testing.NOTE 2Applicable methods for the preparation of test panels andsubstrates are given in Practices D609 and D1730. Practices D823 coverapplication techniques for the produc
27、tion of uniform films.6.2 It is recommended that a control specimen of a coatingwith known durability and similar failure type be included witheach test. Such control specimens can provide warning ofchanges in test severity in a given apparatus, and can indicatevariations in test severity between di
28、fferent apparatuses. Bestpractice is to use two different control specimens, one withknown relatively poor performance, and one with knownrelatively good performance. The use of control specimenswith known performance can also be used to determine theduration of the test that is required to produce
29、meaningfulresults.6.3 It is recommended that at least two replicate specimensof each different coating be used, so as to compensate forvariations between specimens and potential variations in testconditions with the device. If more than one replicate specimenis exposed, place the replicates in diffe
30、rent locations in theexposure area.7. Procedure7.1 Generate the saturated water vapor with reagent waterconforming to at least the requirements of Type IV of Speci-fication D1193.7.2 Unless otherwise specified, adjust the temperature of thesaturated air and water vapor mixture so that the air temper
31、a-ture next to the test specimens is 38C. During equilibriumoperation, the temperature of the sensor used to measure the airnext to the specimens can vary by a maximum of 62C fromthe desired temperature. If a temperature set point differentfrom 38C is used, it must be included in the Test Report.7.2
32、.1 The temperature of the water vapor will typically bethe same or higher than the air temperature next to thespecimens. This is a requirement in order for this procedure towork correctly. The temperature of the water in the vaporgeneration is not set by this practice but water vapor tempera-tures t
33、hat are greater than 38C tend to make condensationmore uniform over the test specimens.NOTE 3Due to heat loss to the specimens and the walls of thechamber, the temperature of the water in the tank will be above thetemperature of the air and water vapor mixture.7.3 Support flat specimens approximatel
34、y 15 from thevertical with the front side facing up. Slotted nonmetallicsupports are suitable for flat specimens. Position 3-dimensionalspecimens on a support so that the primary surface is as closeto end-use position as possible. Material used for supports shallbe of sufficient stiffness so that th
35、ey do not distort or sag duringprolonged use. The minimum distance between adjacent speci-mens or between specimens and the walls of the chamber shallbe at least 30 mm. Arrange specimens so that condensate fromone specimen cannot drip on other specimens.D2247 1127.4 Droplets of condensation shall ap
36、pear evenly on thespecimen at all times if the chamber is operating properly.Before using the exposure device to this standard for the firsttime, verify the exposure area for condensation uniformity inaccordance with the procedure described in Annex A1. Re-verify the chamber if there are any changes
37、 to the setup of theequipment or if any of the components listed in Section 5 arerepaired or replaced. Operate the test continuously with the testchamber closed unless otherwise specified. Short interruptionsto inspect or remove specimens are permitted, but suchinterruptions should occur no more tha
38、n once each day.7.5 To control for variability within the apparatus, reposi-tion the specimens on a regular basis so that all specimensspend equivalent amounts of time in the various areas of theapparatus (front, back, left, right, and center).7.6 Conclude the test after a specified period of time o
39、r aftereffects from exposure to water are observed.7.7 Wipe the test specimens dry. Rate specimens forchanges in color, blistering, etc. Evaluate specimens no lessthan 5 min and no more than 10 min after removal from test,as the effects from water exposure can change within a shorttime. Remove only
40、as many specimens as can be rated withinthe specified time.NOTE 4 Relevant procedures for evaluating water effects are de-scribed in Practice D610 and Test Methods D714, D1654, D2616, D3359,D3363, D4541.7.7.1 If possible, rate the specimens again after they havebeen removed from the test for a recov
41、ery period long enoughthat moisture absorbed within the specimens dries out and thespecimens reach moisture equilibrium with room air. A recov-ery period from 12 to 24 h is generally sufficient. Thepost-recovery rating allows evaluation of the permanent effectsof the exposure as distinct from the tr
42、ansient effects, and isespecially important for evaluation of color and gloss.8. Report8.1 Report the following information:8.1.1 Sample identification.8.1.2 Results of the evaluation(s).8.1.3 Reference to Practice D2247.8.1.4 Hours of test duration.8.1.5 Test temperature.8.1.6 Special conditions of
43、 test or any deviations in testprocedure.9. Keywords9.1 adhesion; blistering; humidity; resistance-water; rustANNEX(Mandatory Information)A1. VERIFICATIONA1.1 Chamber Verification ProcedurePlace at least 17specimens throughout the planned exposure area with one atthe center and four each uniformly d
44、istributed in each quadrantof the planned exposure area. Fig. A1.1 is a diagram ofplacement of specimens for chamber verification. After thespecimens have been in an unopened chamber for at least 12 h,open the chamber and check for the presence of uniformcondensation on each specimen. Specimens used
45、 for chamberverification shall be at least as tall as the tallest specimensevaluated in normal testing. The minimum distance betweenspecimens used for chamber verification and the wall of thechamber is 75 mm. The minimum distance between adjacenttest specimens is 150 mm. If any specimen does not hav
46、econdensation, or the condensation is present on only part of thespecimen surface, the area within 6100 mm (4 in.) of thespecimen position shall not be used for testing.FIG. A1.1 Diagram of Specimen Placement for Mapping Chamber for Condensation UniformityD2247 113APPENDIX(Nonmandatory Information)X
47、1. APPARATUSX1.1 The apparatus must be constructed so that heatedwater vapor is generated or introduced at the bottom of thechamber. This saturates the air in the lower portion of the testchamber with water vapor. The saturated mixture of watervapor and air temperature rises and then cools below the
48、 dewpoint, causing condensation on the specimens. Three types ofapparatus have been found to meet the requirements of thispractice. One type uses a water tank with an electric immersionheater, another uses a water vapor generator, and the third typeuses a submerged air distribution pipe.X1.2 In cham
49、bers using a water tank with electric immer-sion heater to supply heat and humidity, the area of the heatedwater tank should be limited to no more than 25 % of the floorarea of the chamber. The use of a large heated water tank wouldtend to make the temperature within the chamber uniform, andthus inhibit or prevent the formation of condensate on thespecimens. The water temperature will be approximately from5 to 10C (10 to 20F) above the vapor temperature when thewater tank and chamber are properly proportioned.X1.3 In chambers using a water jacket to supply heat andhu
