ASTM F1110-2008 Standard Test Method for Sandwich Corrosion Test.pdf

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1、Designation: F 1110 08Standard Test Method forSandwich Corrosion Test1This standard is issued under the fixed designation F 1110; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses in

2、dicates 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. Scope1.1 This test method defines the procedure for evaluatingthe corrosivity of aircra

3、ft maintenance chemicals, when presentbetween faying surfaces (sandwich) of aluminum alloys com-monly used for aircraft structures. This test method is intendedto be used in the qualification and approval of compoundsemployed in aircraft maintenance operations.1.2 The values stated in SI units are t

4、o be regarded as thestandard. The values given in parentheses are for information.1.3 This standard may involve hazardous materials, opera-tions, and equipment. This standard does not purport toaddress all of the safety concerns, if any, associated with itsuse. It is the responsibility of the user o

5、f this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.Specific hazard statements appear in Section 9.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 1748 Test Method for Rust Prot

6、ection by Metal Preser-vatives in the Humidity CabinetG46 Guide for Examination and Evaluation of PittingCorrosion2.2 Industry Standards:3SAE-AMS-QQ-A-250/4 Al Alloy 2024, Plate and SheetSAE-AMS-QQ-A-250/5 Al Alloy Alclad 2024, Plate andSheetSAE-AMS-QQ-A-250/12 Al Alloy 7075, Plate and SheetSAE-AMS-

7、QQ-A-250/13 Al Alloy Alclad 7075, Plate andSheet2.3 Military Specification:MIL-A-8625 Anodic Coatings for Aluminum and Al Al-loys43. Terminology3.1 Definition of Term Specific to This Standard:3.1.1 sandwich corrosion testa comparative acceleratedenvironmental test of the corrosivity of liquid or so

8、lid materialspresent between faying surfaces of structural aluminum alloyscommonly used in aerospace construction.4. Summary of Test Method4.1 Aluminum coupons having clad or anodized noncladsurfaces are sandwiched together with a filter paper saturatedwith the test material between the coupons. The

9、 sandwichedcoupons are cycled between warm ambient air and warmhumid air for 7 days. The coupons are then inspected todetermine whether corrosion more severe than that caused byreagent water has occurred on the surfaces exposed to the testmaterial. This test method is used for solutions of dry granu

10、larmaterial or for liquid materials.5. Significance and Use5.1 The data generated by this test method shall be used todetermine whether aircraft structural aluminum alloys areliable to be corroded or damaged by application of the testmaterial during routine maintenance operations.5.2 Interpretation

11、of the sandwich corrosion test results isbased on a comparison of the appearance of faying surfaces ofthree sets of coupons. One set of test coupons is exposed withreagent water only in the faying surfaces, to establish thebaseline (controls) against which the panels exposed to the testmaterial are

12、compared. Disregard corrosion at cut edges of thetest coupons.5.3 The relative corrosion severity rating system is providedin order to allow a numerical classification of the test resultsand to eliminate the necessity for elaborate weight lossmeasurements. Pitting corrosion, which is rated 4extensiv

13、e(severe) corrosion, may involve only a negligible weight loss.1This test method is under the jurisdiction of ASTM Committee F07 onAerospace and Aircraft and is the direct responsibility of Subcommittee F07.07 onQualification Testing of Aircraft Cleaning Materials.Current edition approved May 1, 200

14、8. Published June 2008. Originallyapproved in 1986. Last previous edition approved in 2002 as F 1110 02.2For 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 standard

15、s Document Summary page onthe ASTM website.3Available from Society of Automotive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001.4Available from Department of Defense Single Stock Point (DODSSP); http:/dodssp.daps.dla.mil1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C7

16、00, West Conshohocken, PA 19428-2959, United States.5.4 Relative corrosion severity rating system:Appearance/Corrosion:0No visible corrosion and no discoloration present1Very slight corrosion or very slight discoloration, and/or up to 5 % of areaAcorroded2Discoloration and/or up to 10 % of areaAcorr

17、oded3Discoloration and/or up to 25 % of areaAcorroded4Discoloration and/or more than 25 % of areaAcorroded, and/or pittingpresentA”Area” refers to area under the filter paper, or if no filter paper is used, the areawhere the test material was applied.6. Interferences6.1 It is possible that tap water

18、 containing large amounts ofdissolved solids, especially chlorides, will cause relative severecorrosion of the aluminum control panels. For this reason,reagent water is specified. For comparative purposes, a set ofaluminum test panels, with the locally available tap waterapplied to the filter paper,

19、 is sometimes run along with thereagent water panels.6.2 Filter paper made from glass fibers is not recommendedsince, in practice, corrosion of the control panels has often beenfound.7. Apparatus7.1 Humidity Test Cabinet, as specified in Test MethodD 1748 or equal, capable of maintaining 95 to 100 %

20、 relativehumidity at 37.7 6 1C (100 6 2F).7.2 Oven, forced air circulation, capable of maintaining 37.76 1C (100 6 2F).7.3 Microscope, binocular, 103 to 403.8. Reagents and Materials8.1 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as defined

21、by Specification D 1193, Type IV.8.2 Aluminum Alloy Coupons:8.2.1 Aluminum alloy coupons shall conform to the follow-ing industry standards:SAE-AMS-QQ-A-250/4, 2024-T3 noncladSAE-AMS-QQ-A-250/5, 2024-T3 AlcladSAE-AMS-QQ-A-250/12, 7075-T6 noncladSAE-AMS-QQ-A-250/13, 7075-T6 Alclad8.2.2 Coupon SizeThe

22、 recommended coupon size 50 by100 by 1.0 to 1.5 mm (2 by 4 by 0.04 to 0.06 in.) has beenfound to provide suitable results for comparative tests. Smallersizes are not recommended, because of the increased variationsdue to edge effects. Larger coupons are acceptable, but thespace requirements for test

23、ing and storage shall be taken inconsideration.8.3 Anodize the nonclad coupons in accordance with Mili-tary Specification MIL-A-8625, Type 1 (Chromic Acid) fol-lowed by a hot water seal.8.4 Filter PaperUse Whatman No. 5 or equal filter papermade from cellulose, 11 or 13 cm. Filter paper is not requi

24、redwhen the material being tested is a solid. In case no filter paperis used, the area covered by the test material shall also beapproximately 25 by 75 mm (1 by 3 in.).9. Hazards9.1 The materials used for aircraft maintenance sometimescontain flammable solvents, strong acids or alkalis, or othertoxi

25、c compounds. Take suitable precautions to prevent personalinjury from these hazards. When the composition of the testmaterial is not known, consult the manufacturer to determinewhether any hazards exist.9.2 Exercise special care in handling the chromic acidsolution, specified in 8.3, for its etching

26、 properties.10. Sampling10.1 Agitate or thoroughly mix the test material to assureuniformity. Where dilution of the material is required, usereagent water or the solvent specified by the product manufac-turer. Apply sufficient test material to saturate the area betweenthe metal coupons.11. Test Spec

27、imen11.1 Prepare three sets of test panels. A test panel set shallconsist of eight individual test coupons, sandwiched together inpairs of coupons of the same alloy and the same surfacetreatment, to provide four test coupon sandwiches for each testcondition. Identify each coupon by impression stampi

28、ng orother suitable permanent method.11.2 Clean the panels by solvent wiping, or vapor degreas-ing. Do not use acid or caustic cleaners. Remove ink stampedmarkings from the panels. Do not use abrasive materials toclean the panels.11.3 Prepare the test panel sets as follows for each alloy:11.3.1 One

29、set for the compound to be tested at use dilution,11.3.2 One set for the compound to be tested in concen-trated form and11.3.3 One set for controls using reagent water.12. Preparation of Apparatus12.1 Verify that the humidity cabinet is operating at thespecified temperature and humidity.12.2 Verify

30、that the oven is operating at the specifiedtemperature, with air circulation.13. Calibration and Standardization13.1 Since the test coupons include controls for comparativepurposes, no special calibration or standardization proceduresare required.14. Conditioning14.1 Conditioning of the test materia

31、ls or the sets ofprepared test coupons is not required. Thoroughly agitate thetest sample before application to the test coupons.14.2 Allow the anodized panels to age for a period of atleast 48 h prior to exposure.15. Procedure15.1 Assemble the cleaned panels into three identicalgroups each having f

32、our different sets of panels suitablyidentified by permanent marking. Each panel set shall consistof two individual coupons of the same alloy and the samesurface treatment.F111008215.2 Cut a piece of cellulose filter paper to approximate 25by 75 mm (1 by 3 in.). Fit this piece over one of the coupon

33、s.Add the test solution at the use concentration to the paper untilsaturated. Cover the wet paper with the second coupon of thesandwich pair. Each sandwich shall be held together withwaterproof tape, with no more than a 25 mm (1 in.) piece oftape, maximum width 20 mm (0.8 in.), on each of two opposi

34、tesides. Repeat the operation for each of the coupon sets in thegroup. This test may be omitted if the test material is to be usedin the concentrated form only. See 8.4 for deletion of the filterpaper.15.3 Prepare a second group of panels as outlined in 15.2except apply the material to be treated in

35、 the concentratedas-received condition, without dilution by water or solvents.(Not applicable to dry granular materials.)15.4 Prepare a third group of panels, as outlined in 15.2,except apply reagent water only to the filter paper between thepanels.15.5 During each test day, expose the panels in the

36、 oven for8 h followed immediately by exposure in the humidity cabinet.Preferably start the alternating exposure periods on a Mondaymorning with the initial exposure in the oven. Over thefollowing weekend, the coupons are to be left in the humiditycabinet. Maintain the humidity cabinet at 37.7 6 1C (

37、100 62F) and 95 to 100 % relative humidity. Maintain the oven at37.7 6 2.8C (100 6 5F). Expose each set of panelsindividually, not stacked, in a horizontal position. After expo-sure, rinse the panels in warm tap water, and scrub lightly witha soft nonmetallic bristle brush. Rinse with reagent water

38、inaccordance with Specification D 1193, Type IV at room tem-perature. After drying, examine each panel under 103 magni-fication, and rate each set according to the scale in 5.4.16. Interpretation of Results16.1 Compare the corrosion rating on the set of panels fromthe first and second groups with th

39、ose from the third, Reagentwater, control group. Any corrosion in excess of that shown bygroup 3 shall be cause for rejection. Give pitting corrosion ofany panel a severity rating of 4. Disregard any corrosion at theedges of the panel. Compare only those surfaces which wereunder the filter paper, un

40、less no filter paper has been used. Inthis case, the rating is to be determined on the areas which havebeen in direct contact with the test material. Pitting is definedin Guide G46.17. Report17.1 Prepare a report certifying that the test has been run inaccordance with this test method and listing th

41、e exact condi-tions of the test as performed. Tabulate the corrosion rating ofall test panels used in the test, and state whether the testcompound is considered to be acceptable from a sandwichcorrosion standpoint.18. Precision and Bias18.1 No statement is made about either the precision or biasof t

42、his test method since the result merely states whether thereis conformance to the criteria for success specified in theaccompanying material or process specification of the materialbeing tested, or both.19. Keywords19.1 aircraft maintenance chemicals; aluminum structuralaircraft alloys; faying surfa

43、ces; sandwich corrosionAPPENDIX(Nonmandatory Information)X1. RECOMMENDED PANEL IDENTIFICATION, TABULATION OF RESULTS, ANDEXPOSURE SCHEDULEX1.1 Panel Identification:X1.1.1 Test Material Diluted to Use Concentration:A-1 2024-T3 Nonclad AnodizedA-2 2024-T3 AlcladA-3 7075-T6 Nonclad AnodizedA-4 7075-T6

44、AlcladX1.1.2 Test Material in Concentrated, As-Received Condi-tion:B-1 2024-T3 Nonclad AnodizedB-2 2024-T3 AlcladB-3 7075-T6 Nonclad AnodizedB-4 7075-T36 AlcladX1.1.3 Specification D 1193, Type IV Control:C-1 2024-T3 Nonclad AnodizedC-2 2024-T3 AlcladC-3 7075-T6 Nonclad AnodizedC-4 7075-T6 AlcladX1.

45、2 Tabulation of Results:X1.2.1 See Fig. X1.1 for a recommended form for tabula-tion of results.X1.3 Exposure Schedule:X1.3.1 See Table X1.1 for a recommended exposure sched-ule.F1110083ASTM International takes no position respecting the validity of any patent rights asserted in connection with any i

46、tem mentionedin 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 co

47、mmittee and must be reviewed every five years andif not 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

48、 meeting of theresponsible 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 Dri

49、ve, 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).TABLE X1.1 Recommended Exposure ScheduleAStepExposure Time,Bh 612ConditionsTemperatureC (F)Relative Humidity, %1 8 37.7 (100) Ambient2 16 37.7 (100) 951003 8 37.7 (100) Ambient4 16 37.7 (100) 951005 8 37.7 (100) Ambient6 16 37.7 (100) 951007 8 37.7 (100) Ambi