1、Designation: E 864 08Standard Practice forSurface Preparation of Aluminum Alloys to Be AdhesivelyBonded in Honeycomb Shelter Panels1This standard is issued under the fixed designation E 864; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year of last revision. 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. Scope1.1 This practice cov
3、ers the preparation of clean uniformsurfaces of aluminum alloys suitable for formation of durableadhesive bonds to nonmetallic honeycomb materials in themanufacture of sandwich panels for tactical shelters.1.2 This standard does not purport to address all of thesafety concerns, if any, associated wi
4、th 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. For a specificwarning statement, see 5.2.1.2. Referenced Documents2.1 ASTM Standards:2D 2674 Methods of Anal
5、ysis of Sulfochromate Etch Solu-tion Used in Surface Preparation of AluminumD 3167 Test Method for Floating Roller Peel Resistance ofAdhesivesE 865 Specification for Structural Film Adhesives for Hon-eycomb Sandwich PanelsE 866 Specification for Corrosion-Inhibiting AdhesivePrimer for Aluminum Alloy
6、s to Be Adhesively Bonded inHoneycomb Shelter Panels2.2 APHA Standard:3APHA Standard Methods for the Examination of Water andWaste Water (15th Edition, 1980), Sections 402, 403, and4083. Significance and Use3.1 Durable adhesive bonds to aluminum alloys can beobtained reliably only through proper sel
7、ection and carefulcontrol of the materials used and the steps in the bondingprocess. The preparation of the aluminum alloys to obtainclean, uniform surfaces with appropriate characteristics is acritical step. This practice describes how such surfaces can beobtained.4. Apparatus4.1 General Processing
8、:4.1.1 All heated tanks shall be equipped with automatictemperature controls and shall have means for agitation toprevent local overheating of the solution. Solutions may beheated by any internal or external means that do not changetheir compositions. Steam shall not be introduced into anysolution.
9、Compressed air introduced into any solution orequipment shall have been filtered to remove oil and moisture.4.1.2 Tanks shall be made from, or lined with, materials thathave no adverse effects on the solutions used or the parts beingtreated. All tanks shall be of sufficient size to allow completeimm
10、ersion of the largest part or assembly to be treated.4.2 Rinse TanksImmersion rinse tanks shall be equippedwith a means for skimming or overflowing or both to removesurface contamination. The tanks shall be equipped with ameans for flushing hollow sections.4.3 RinsesRinses, other than final rinses,
11、shall be main-tained in such a manner to prevent carryover of materials thatwould adversely affect the next solution (for example, using afog water rinse as the aluminum part/assembly is beingwithdrawn from the rinse tank).5. Materials5.1 WaterWater used for makeup of processing solutionsand final r
12、insing shall be deionized water or shall meet therequirement of Table 1.Analyses shall be performed as often asnecessary to assure that the water meets the requirements.Samples for analysis shall be collected at the processing tanks.5.2 Etch Solution:5.2.1 Method I, Sulfo-Chromate Etch (FPL)The chem
13、icalanalysis of the etch solution shall be maintained at approxi-mately 30 parts by mass of water, ten parts by mass of sulfuricacid (sp gr 1.84), and one to four parts by mass of sodiumdichromate. Prior to use, a minimum of 0.06 part by mass of1This practice is under the jurisdiction of ASTM Commit
14、tee E06 on Perfor-mance of Buildings and is the direct responsibility of Subcommittee E06.53 onMaterials and Processes for Durable Rigidwall Relocatable Structures.Current edition approved Nov. 1, 2008. Published December 2008. Originallyapproved in 1982. Last previous edition approved in 2003 as E
15、864 03.2For 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.3Available from the American Public Health Association
16、 (APHA), 800 I Street,NW, Washington, DC 20001-3710, http:/www.apha.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.dissolved 2024 aluminum shall be added. (WarningIt isrecognized that chromates present a hazard to health. Use an
17、ddisposal procedures are governed by Federal and Local EPAand DER limitations.5.2.2 Method II, Sulfo-Ferric Etch (P2)The chemicalanalysis of the etch solution shall be maintained at approxi-mately 27 to 36 % by weight of sulfuric acid (sp gr 1.84) and2.9 to 4.7 oz/gal of ferric iron or 18 to 22 oz/g
18、al of ferricsulfate. This is the equivalent of 2 gal of concentrated sulfuricacid and 12.5 lb of ferric sulfate in every 10 gal of solution.Two gallons of a 50 % ferric sulfate solution may be used inplace of the 12.5 lb of the powdered ferric sulfate.NOTE 1Only virgin ferric sulfate solution shall
19、be used in thisprocess. Impurities in reclaimed ferric sulfate will cause unwantedreactions when the aluminum is treated.5.3 Alkaline Cleaning SolutionNonetch, alkaline cleaningsolution shall be prepared in accordance with the manufactur-ers recommendations, or as indicated in 7.1.2. When thealuminu
20、m being cleaned is immersed in the alkaline cleaner forthe time and at the temperature used for processing, there shallbe no evidence of gas evolution, etching, or metal removal. Thealkaline solution shall not contain silicates.5.4 QualityAssuranceAdhesiveThe adhesive system usedfor the quality assu
21、rance tests of 8.6 shall meet SpecificationE 865. The adhesive shall be changed only when a batch isalmost exhausted so the results of any particular days testingcan be directly compared to the results of previous tests. Whena change is made in the batch or lot of adhesive used, anadditional set of
22、tests shall be made to compare the old batchor lot with the new one to establish a basis for comparisonbetween the results obtained with each.6. Test Methods6.1 Chemical AnalysesPerform chemical analyses of thewater and solutions as indicated in 6.2 and 6.3. Analyze asoften as necessary to maintain
23、the required concentrations at aminimum of every day of operation. If a process is not in useduring the normal analysis period, note this on the analysisrecord and analyze the solution prior to further use.6.2 Water AnalysesAnalyze as described in APHA Stan-dard Methods for the Examination of Water
24、and Waste Water.6.3 Etch Solution Analysis:6.3.1 Sulfo-Chromate EtchPerform the analyses in accor-dance with Methods D 2674.6.3.2 Sulfo-Ferric EtchPerform the analyses in accor-dance with 6.3.2.1 and 6.3.2.2.6.3.2.1 Sulfuric AcidPipet a 1-mL (0.03-oz) sample into a250-mL (8.5-oz) Erlenmeyer flask co
25、ntaining 100 mL (3.4 oz)of distilled water. Add 1 g (0.03 oz) of tribasic sodium citrateand 1 g (0.03 oz) of sodium fluoride. Add 2 to 3 drops ofphenolphthalein indicator. Titrate with 0.4 N sodium hydroxideto clear or faint pink. Calculate the normality of sulfuric acid inaccordance with Table 2.6.
26、3.2.2 Ferric IonPipet a 2-mL (0.06-oz) sample into a250-mL (8.5-oz) Erlenmeyer flask containing 100 mL (3.4 oz)of distilled water. Add 10 mL (0.3 oz) of concentratedhydrochloric acid. Add 1 to 2 g (0.03 to 0.06 oz) of potassiumiodide titrate with 0.10 N sodium thiosulfate to a greenishcolor. Add abo
27、ut 2 mL of starch solution. Continue titration toa clear green end point. Calculate ferric sulfate as follows:mL sodium thiosulfate used 3 2.79 5 g/L ferric ion (1)6.4 Visual InspectionInspect parts visually for stains andwater break.6.5 Floating Roller Peel TestTest in accordance with TestMethod D
28、3167.7. Procedure7.1 Surface PreparationPerform the steps of the proce-dure in accordance with 7.1.1-7.1.5 and Table 3 or Table 4 asappropriate. Observe the restrictions listed in 7.2.7.1.1 PrecleaningRemove visible oil and grease from thealuminum by vapor degreasing, solvent cleaning, or othersuita
29、ble method to ensure a clean, nonoily surface.7.1.2 Alkaline CleaningImmerse the aluminum in thealkaline cleaning solution held from 50 to 80C (122 to 176F)for a minimum of 5 min. Follow the alkaline cleaning bythoroughly rinsing in water from room temperature to 70C(158F). When the immersion does n
30、ot completely clean thealuminum, alkaline cleaning shall be repeated. Keep the partswet between the alkaline treatment and immersion in the rinsetank.7.1.3 Etching:7.1.3.1 Sulfo-Chromate EtchImmerse the aluminum partsin the etch solution for 9 to 15 min from 65 to 70C (149 to158F). Keep the parts we
31、t between the etch tank and the rinsetank. Follow the etching by thoroughly rinsing with roomtemperature water.7.1.3.2 Sulfo-Ferric EtchImmerse the aluminum parts inthe etch solution for 10 to 20 min from 49 to 65C (120 to149F). Immerse the flat sheet for 10 to 12 min. Extrusionsmay require up to 20
32、 min. Keep the parts wet between the etchtank and the rinse tank. Follow the etching by thoroughlyrinsing in water at 55C (131F) maximum.TABLE 1 Requirements for Water to Be Used in Solutions andRinsesRequirementsMin MaxpH 6.0 8.0Total solids, ppm . 200Total alkalinity as CaCO3, ppm . 125Chloride co
33、ntent, ppm . 15TABLE 2 Calculation of Normality of Sulfuric Acid to Percent byWeight (1 g/100 g)NOTEN sulfuric acid = mL 0.4 N NaOH 3 0.4N % N %4.65=20 7.76=314.91=21 8.06=325.18=22 8.37=335.45=23 8.68=345.73=24 8.99=356.01=25 9.31=366.29=26 9.64=376.58=27 9.96=386.86 = 28 10.3 = 397.16 = 29 10.6 =
34、407.46 = 30E8640827.1.4 Final RinseRinse the aluminum for 1 to 2 min inwater from room temperature to 55C (131F). Check partsthat can be readily observed for water break and recycle if awater break occurs. Verify the water break-free surface for30 s. If the water film does not remain continuous for
35、30 s,repeat surface preparation procedure (see 7.1.4.1).NOTE 2A water break-free surface maintains a continuous water film(no beads) for a period of at least 30 s after being sprayed or immersionrinsed in clean water at a temperature below 38C (100F).7.1.4.1 ReworkParts that are rerun, because of wa
36、terbreak, stains, or unprimed parts that have exceeded thepermitted storage time shall be reworked no more than twotimes. Do not exceed a total immersion time of 34 min.7.1.5 DryingAir dry the aluminum for not more than 1 hat a temperature not exceeding 65C (149F) prior to move-ment to the controlle
37、d area.7.2 Restrictions:7.2.1 Immerse parts completely in all solutions.7.2.2 Do not allow rinsing stains and dichromate stains onthe bonding surfaces.7.2.3 Place cleaned dried parts within12 h in a controlledarea with filtered air that is maintained at a relative humidity of50 % maximum. Prime or b
38、ond the cleaned parts within 16 h.7.2.4 Do not allow the solution temperature to exceed 63C(145F) when changing a new sulfo-ferric etch tank.7.2.5 Take precautions to prevent precipitation (keep spentsolution warm in transport) when taking spent sulfo-ferric etchsolution to a waste disposal facility
39、.8. Quality Assurance8.1 HandlingParts that have been processed shall behandled using clean cotton gloves.8.2 Marking and StoringAll processed parts shall bemarked with the date or time of processing, or both. Theprocessed parts shall not be marked on the faying surfaces.8.3 RecordsRecords of all te
40、sts required by this practiceshall be maintained by the processor for a minimum period ofthree years or, at the option of the processor or the request ofthe purchaser, the records may be forwarded to the purchaser.8.4 Written Process ProceduresEach processor shall keepa written description of the pr
41、ocess procedure in the processarea. The description shall include, as a minimum, the follow-ing information: (1) processing time for each step, (2) process-ing temperatures for each step, and (3) materials used for eachstep. The description of the procedure shall be signed by theindividual responsib
42、le for process control and shall be updatedas necessary to ensure conformance with requirements.8.5 Visual InspectionParts shall be inspected for compli-ance with 7.1.4 and 7.2.2.8.6 Quality Assurance TestControl specimens are re-quired when processing for structural bonding. One set of testspecimen
43、s shall be processed each day with a typical produc-tion load. A test coupon shall be bonded, cut into specimens,and tested in accordance with 8.6.1. Failure of these specimensto meet the minimum acceptable average peel strength shallwarrant an immediate investigation to determine the cause.8.6.1 Fl
44、oating Roller Peel SpecimenA minimum accept-able average floating roller peel strength for the adhesive shallbe established prior to its use in quality assurance tests.Thereafter, five unprimed specimens cut from one test couponshall be prepared and tested at the start of each daysproduction as desc
45、ribed in 6.5. The adhesive used shall be asdefined in 5.4, and the average peel strength for the fivespecimens shall not be less than that minimum established forthat adhesive.NOTE 3If the customer does not require use of a primer (SpecificationE 866) in shelter panel manufacture, then only five unp
46、rimed specimensshall be prepared and tested each day.TABLE 3 Procedure for Surface Preparation of Aluminum AlloysUsing the Sulfuric Acid-Sodium Dichromate EtchSTEP 1PRECLEAN (see 7.1.1)Vapor degrease or clean with safety solvent. Flush all hollow sections.Repeat as necessary.STEP 2ALKALINE CLEAN (se
47、e 7.1.2)Immerse in aluminum cleaner from 50 to 80C (122 to 176F) for 5 to 10 min.Repeat as necessary.STEP 3RINSE (see 7.1.2)Use water from room temperature to 70C (158F).STEP 4ETCH (see 7.1.3.1)Immerse in sulfuric acid-sodium dichromate etch for 9 to 15 min from 65 to70C (149 to 158F). Spray rinse h
48、eavy sections as they emerge from thesolution as necessary to prevent staining.STEP 5RINSE (see 7.1.3.1)Use room temperature water.STEP 6FINAL RINSE (see 7.1.4)Use water from room temperature to 50C (122F) for 1 to 2 min.STEP 7DRY (see 7.1.5)Use air from room temperature to 65C (149F) for not more t
49、han 1 h.TABLE 4 Procedure for Surface Preparation of Aluminum AlloysUsing the Sulfo-Ferric EtchSTEP 1PRECLEAN (see 7.1.1)Vapor degrease or clean with safety solvent. Flush all hollow sections.Repeat as necessary.STEP 2ALKALINE CLEAN (see 7.1.2)Immerse in aluminum cleaner at 50 to 80C (122 to 176F) for 5 to 10 min.Repeat as necessary.STEP 3RINSE (see 7.1.2)Use water from room temperature to 70C (158F).STEP 4ETCH (see 7.1.3.2)Immerse in the sulfo-ferric etch for 1020 min from 49 to 65C (120 to149F). S
