1、Designation: D 5894 05Standard Practice forCyclic Salt Fog/UV Exposure of Painted Metal, (AlternatingExposures in a Fog/Dry Cabinet and a UV/CondensationCabinet)1This standard is issued under the fixed designation D 5894; the number immediately following the designation indicates the year oforiginal
2、 adoption or, in the case of revision, the year of last revision. A 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 practice covers basic principles and operatingpractice for cy
3、clic corrosion/UV exposure of paints on metal,using alternating periods of exposure in two different cabinets:a cycling salt fog/dry cabinet, and a fluorescent UV/condensation cabinet.1.2 This practice is limited to the methods of obtaining,measuring, and controlling exposure conditions, and proce-d
4、ures. It does not specify specimen preparation nor evaluationof results.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use
5、. 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:2D 610 Test Method for Evaluating Degree of Rusting onPainted Steel SurfacesD
6、 714 Test Method for Evaluating Degree of Blistering ofPaintsD 1654 Test Method for Evaluation of Painted or CoatedSpecimens Subjected to Corrosive EnvironmentsD 4587 Practice for Fluorescent UV-Condensation Expo-sures of Paint and Related CoatingsG85 Practice for Modified Salt Spray (Fog) TestingG1
7、13 Terminology Relating to Natural and ArtificialWeathering Tests of Nonmetallic MaterialsG 147 Test Method for Measuring Abrasion ResistanceMaterials by Abrasive Loop ContactG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices That Use Laboratory Light SourcesG 152 Practic
8、e for Operating Open Flame CarbonArc LightApparatus for Exposure of Nonmetallic MaterialsG 154 Practice for Operating Fluorescent Light Apparatusfor UV Exposure of Nonmetallic MaterialsG 155 Practice for Operating Xenon Arc Light Apparatusfor Exposure of Non-Metallic Materials3. Terminology3.1 Defin
9、itionsThe definitions given in TerminologyG113are applicable to this practice.4. Summary of Practice4.1 The test specimens are exposed to alternating periods ofone week in a fluorescent UV/condensation chamber and oneweek in a cyclic salt fog/dry chamber. The fluorescent UV/condensation cycle is 4-h
10、 UV at 0.89 W/(m2 nm) at 340 nm at60C and 4-h condensation at 50C, using UVA-340 lamps.The fog/dry chamber runs a cycle of 1-h fog at ambienttemperature and 1-h dry-off at 35C. The fog electrolyte is arelatively dilute solution, with 0.05 % sodium chloride and0.35 % ammonium sulfate.NOTE 1The irradi
11、ance target setpoint of 0.89 is based upon actualirradiance levels that have been historically widely used for coatings.5. Significance and Use5.1 The outdoor corrosion of painted metals is influenced bymany factors, including: corrosive atmospheres, rain, con-densed dew, UV light, wet/dry cycling,
12、and temperature1This 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 July 1, 2005. Published July 2005. Originally approvedin 1996
13、. Last previous edition approved in 1996 as D 5894 96.2For 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 to the standards Document Summary page onthe ASTM website.1Copyri
14、ght ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.cycling. These factors frequently have a synergistic effect onone another. This practice is intended to provide a morerealistic simulation of the interaction of these factors than isfound in t
15、raditional tests with continuous exposure to a staticset of corrosive conditions.5.2 Results obtained from this practice can be used tocompare the relative durability of materials subjected to thespecific test cycle used.5.3 No single exposure test can be specified as a completesimulation of actual
16、use conditions in outdoor environments.Results obtained from exposures conducted according to thispractice can be considered as representative of actual outdoorexposures only when the degree of rank correlation has beenestablished for the specific materials being tested. The relativedurability of ma
17、terials in actual outdoor service can be verydifferent in different locations because of differences in UVradiation, time of wetness, temperature, pollutants, and otherfactors. Therefore, even if results from a specific artificial testcondition are found to be useful for comparing the relativedurabi
18、lity of materials exposed in a particular exterior envi-ronment, it cannot be assumed that they will be useful fordetermining relative durability for a different environment.5.4 Even though it is very tempting, it is not recommendedto calculate an “acceleration factor” relating x hours oflaboratory
19、exposure to y months of exterior exposure. Differentmaterials and different formulations of the same material canhave significantly different acceleration factors. The accelera-tion factor also varies depending on the variability in rate ofdegradation in the laboratory test and in actual outdoorexpo
20、sure.5.5 This practice is best used to compare the relativeperformance of materials tested at the same time in the sameexposure device. Because of possible variability between thesame type of exposure devices, it is not recommended tocompare the amount of degradation in materials exposed forthe same
21、 duration at separate times, or in separate devicesrunning the same test condition. This practice should not beused to establish a “pass/fail” approval of materials after aspecific period of exposure unless performance comparisonsare made relative to a control material exposed simultaneously,or the
22、variability in the test is rigorously quantified so thatstatistically significant pass/fail judgments can be made.5.6 This practice has been found useful for air-dry industrialmaintenance paints on steel3,4,5,6and zinc-rich primers but itsapplicability has not yet been assessed for galvanized sub-st
23、rates.6. Apparatus6.1 Fluorescent UV-Condensation Exposure Chamber,complying with Practices G 151 and G 154.6.2 UVA-340 Fluorescent Lamps.6.3 Salt Fog/Dry Cabinet, complying with Practice G85,Dilute Electrolyte Cyclic Fog/Dry Test Annex.NOTE 2Committee G03 is developing information to be published i
24、nAppendices of G 151, G 152, G 154, and G 155 for guidance on unifor-mity of conditions in the test chambers and allowed operational fluctua-tions of the set points.7. Test Specimens7.1 The composition and preparation of the substrate, speci-men preparation, and the number of specimens shall be agre
25、edupon prior to testing.7.2 Follow the guidelines of Practice G85 and PracticeD 4587 on the preparation of specimens for the needs of thoseparticular exposures.7.2.1 Follow the guidelines of Practice G 147 on condition-ing and handling of specimens.7.3 Unless otherwise agreed, flat specimens shall b
26、e 75 by150 mm.7.4 Expose at least one control specimen with every test.The control specimen should have known durability and be ofsimilar composition to the test specimens. It is preferable tohave two control materials: one of higher durability and one oflower durability.7.5 It is recommended that a
27、t least three replicates of eachspecimen be tested, to compensate for variation within thechambers and variation between specimens.8. Procedure8.1 Fluorescent UV-Condensation Exposure:8.1.1 Start the exposure in the fluorescent UV-condensationchamber.NOTE 3It has been found that in certain cases the
28、 exposure must startin the fluorescent UV/condensation device in order to get realistic rustingand staining as well as faster corrosion. It is thought that the initial UVdamage to the coating allows the subsequent salt fog to produce a morerealistic corrosion attack on the substrate.8.1.2 Perform th
29、e fluorescent UV-condensation exposure incompliance with Cycle 2 of Practices D 4587 and G 151 andG 154.8.1.3 Unless otherwise specified, set the irradiance level to0.89 W/(m2 nm) at 340 nm. Program a cycle of 4-h UV at60C 6 3C and 4-h condensation at 50C 6 3C.8.1.3.1 If mutually agreed upon by all
30、parties, use ofnon-irradiance controlled devices is permitted, but use of thesedevices must be included in the test report.8.1.4 Use UVA-340 fluorescent lamps.8.1.5 Expose the specimens for a total of 168 h (1 week) inthe fluorescent UV-condensation chamber before transferringthem to the fog/dry cha
31、mber.8.1.6 Other cycles and lamps are acceptable if agreed uponprior to the test, and reported in compliance with Section 10.8.2 Cyclic Salt Fog/Dry Exposure:8.2.1 Perform the cyclic salt fog/dry exposure according toPractice G85, Dilute Electrolyte Cyclic Fog/Dry Test Annex.3Skerry, B. S. and Simps
32、on, C. H., “Combined Corrosion/Weathering Acceler-ated Testing of Coatings for Corrosion Control,” Presented at Corrosion 91, TheNationalAssociation of Corrosion Engineers (NACE)Annual Conference 1991, andavailable from NACE, P.O. Box 218340, Houston, TX 77218.4Simpson, C. H., Ray, C. J., and Skerry
33、, B. S., “Accelerated Corrosion Testingof Industrial Maintenance Paints Using a Cyclic Corrosion Weathering Method,”Journal of Protective Coatings and Linings, Vol 8, No. 5, May 1991, pp. 2836.5Cleveland Society for Coatings Technology, “Correlation of AcceleratedExposure Testing and Exterior Exposu
34、re Sites,” Journal of Coatings Technology,Vol 66, No. 837, October 1994, pp. 4961.6Boocock, S. K., “A Report on SSPC Programs to Research PerformanceEvaluation Methods,” Journal of Protective Coatings and Linings, October 1994,pp. 5158.D58940528.2.2 Program a fog/dry cycle of 1-h fog at ambient tem-
35、perature and 1-h dry-off at 35C at the chambers referencetemperature sensor.8.2.3 Prepare the salt solution with 0.05 % sodium chlorideand 0.35 % ammonium sulfate by weight.8.2.4 Expose the specimens for a total of 168 h in thefog/dry chamber before transferring them back to the fluores-cent UV-cond
36、ensation chamber.8.2.5 Other cycles, temperatures, and electrolytes are ac-ceptable if agreed upon prior to the test, and reported incompliance with Section 10.NOTE 4Higher temperatures usually produce faster degradation, butpossibly at the expense of realism. Longer fog/dry cycles (for example,2-h
37、fog, 2-h dry) have been found to produce slower degradation.8.3 Specimen RotationWhen moving the specimens fromone chamber to another, reposition the specimens so that overthe course of the test each specimen spends equal amounts oftime in each area of the chamber: edges, center, top, bottom.This wi
38、ll help minimize variation in degradation due tovariations in conditions within the chamber.8.4 Do not wash or clean specimens between tests or priorto completion of entire test, or as agreed upon betweenpurchaser and seller prior to testing.8.5 Evaluation of CorrosionMethods that may be usefulfor e
39、valuating the corrosion of the specimens are Test MethodsD 610, D 714, and D 1654. Practice D 4587 also references anumber of other standards that may be used for evaluating theappearance change of the specimens.8.5.1 Evaluate every 336 h or multiples thereof and aftercompletion of testing. Perform
40、evaluation after complete 2 step(UV exposure and Salt Fog/Dry Exposure) cycles only.9. Duration of Exposure9.1 Use one of the following methods to determine theduration of the exposure under this practice:9.1.1 A mutually agreed upon specified number of totalhours,9.1.2 The exposure required to prod
41、uce a mutually agreedupon amount of change in either the test specimens or anagreed upon standard reference specimen, and9.1.3 If no information is available as to an appropriateexposure duration, expose the specimens for a total of 1008 h,or until significant differences in performance between spec
42、i-mens become apparent.10. Report10.1 Report the following information:10.1.1 Test cycle,10.1.1.1 UV/condensation cabinet cycle (for example, 4-hUV at 60C and 4-h condensation at 50C),10.1.1.2 Fog/dry cabinet cycle (for example, 1-h fog atambient temperature and 1-h dry-off at 35C),10.1.1.3 Hours sp
43、ent in each cabinet before transfer fromone cabinet to the other (for example, 168 h in the fog/drycabinet and 168 h in the UV/condensation cabinet),10.1.1.4 The total hours of exposure,10.1.2 Manufacturers designation and wavelength of peakemission for fluorescent lamps, if different than 8.1.4,10.
44、1.3 Electrolyte solution (for example, 0.05 % sodiumchloride and 0.35 % ammonium sulfate by mass),10.1.4 Specimen cleaning standards used or cleaning mate-rials and procedures, and10.1.5 Other information required in Report section ofPractice G85 and Periods of Exposure and Evaluation ofResults sect
45、ion of Practice D 4587.11. Keywords11.1 accelerated aging/testingpaints; corrosion; cycliccorrosion; rust; salt spray; ultravioletASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard a
46、re 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 must be reviewed every five years andif not
47、 revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which y
48、ou 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).D5894053
