1、Designation: E 864 03Standard 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 (e) 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 co
3、vers 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 w
4、ith 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 specificprecautionary statements, see Note 1 of 5.2.2. Referenced Documents2.1 ASTM Standards:D 2674 Te
5、st Method for Analysis of Sulfochromate EtchSolution 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 fo
6、r Aluminum Alloys to Be Adhesively Bonded inHoneycomb Shelter Panels2.2 APHA Standard:Sections 402, 403, and 408 of Standard Methods for theExamination of Water and Waste Water (15th Edition,1980)23. Significance and Use3.1 Durable adhesive bonds to aluminum alloys can beobtained reliably only throu
7、gh proper selection 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 Gener
8、al Processing: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
9、anysolution. 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 allo
10、w completeimmersion 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 f
11、inal rinses, shall be main-tained in such a manner to prevent carryover of materials thatwould adversely affect the next solution.5. Materials5.1 WaterWater used for makeup of processing solutionsand final rinsing shall be deionized water or shall meet therequirement of Table 1.Analyses shall be per
12、formed 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 chemicalanalysis of the etch solution shall be maintained at approxi-mately 30 parts by mass of w
13、ater, 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 ofdissolved 2024 aluminum shall be added.1This practice is under the jurisdiction of ASTM Committee E06 on Perfor-mance of Buildings and is the direct
14、 responsibility of Subcommittee E06.53 onMaterials and Processes for Durable Rigidwall Relocatable Structures.Current edition approved Oct. 1, 2003. Published October 2003. Originallyapproved in 1982. Last previous edition approved in 1998 as E 864 98e1.2Available from the American Public Health Ass
15、n., 1015 15th St. N.W.,Washington, DC 20005.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.NOTE 1It is recognized that chromates present a hazard to health. Useand disposal procedures are governed by Federal and Local EPA and DERlim
16、itations.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/gal of ferricsulfate. This is the equivalent of 2 gal of concentrated
17、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 2Only virgin ferric sulfate solution shall be used in thisprocess. Impurities in reclaimed ferric sulfate will c
18、ause 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 thealuminum being cleaned is immersed in the alkaline cleaner forthe time and a
19、t the temperature used for processing, there shallbe no evidence of gas evolution, etching, or metal removal. Thealkaline solution shall not contain silicates.5.4 Quality Assurance AdhesiveThe adhesive system usedfor the quality assurance tests of 8.6 shall meet SpecificationE 865. The adhesive shal
20、l 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 tests shall be made to compare the old batchor lot with the new one
21、 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 the required concentrations at aminimum of every day of operation.
22、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 and Waste Water.6.3 Etch Solution Analysis:6.3.1 Sulfo-Chromate Etc
23、hPerform the analyses in accor-dance with Test Method 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 containing 100 mL (3.4 oz)of distilled water. Add 1 g (0.03 oz) o
24、f 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 2.6.3.2.2 Ferric IonPipet a 2-mL (0.06-oz) sample into a250-mL (8.5
25、-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 about 2 mL of starch solution. Continue titration toa clear green
26、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 3167.7. Procedure7.1 Surface PreparationPerform the steps of th
27、e 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 othersuitable method to ensure a clean, nonoily surface.7.1.2 Alkaline Cl
28、eaningImmerse 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 not completely clean thealuminum, alkaline cleaning shall be rep
29、eated. 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 wet between the etch tank and the rinsetank. Follow the etching b
30、y 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 min. Keep the parts wet between the etchtank and the rinse tan
31、k. 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 content, ppm . 15TABLE 2 Calculation of Normality of Sulfuric Aci
32、d 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 = 407.46 = 30E8640327.1.4 Final RinseRinse the aluminum for 1 to
33、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 for 30s. If the water film does not remain continuous for 30 s, repeatsurface preparation procedure (see 7.1.4.1).NOTE 3A
34、 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 waterbreak, stains, or unprimed parts that have exceeded thepermi
35、tted 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 controlled area.7.2 Restrictions:7.2.1 Immerse parts completely in all s
36、olutions.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 bond the cleaned parts within 16 h.7.2.4 Do not allow the soluti
37、on 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.8. Quality Assurance8.1 HandlingParts that have been processed
38、 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 tests required by this practiceshall be maintained by the process
39、or 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 process procedure in the processarea. The description shall inclu
40、de, as a minimum, the follow-ing information: (a) processing time for each step, (b) process-ing temperatures for each step, and (c) materials used for eachstep. The description of the procedure shall be signed by theindividual responsible for process control and shall be updatedas necessary to ensu
41、re 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 testspecimens shall be processed each day with a typical produc-tion load.
42、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 Floating Roller Peel SpecimenA minimum accept-able average floati
43、ng 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 described in 6.5. The adhesive used shall be asdefined in 5.4, and
44、the average peel strength for the fivespecimens shall not be less than that minimum established forthat adhesive.NOTE 4If the customer does not require use of a primer (SpecificationE 866) in shelter panel manufacture, then only five unprimed specimensshall be prepared and tested each day.TABLE 3 Pr
45、ocedure 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 (see 7.1.2)Immerse in aluminum cleaner from 50 to 80C (122 to 176F
46、) 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 heavy sections as they emerge from thesolution as necessary to p
47、revent 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 than 1 h.TABLE 4 Procedure for Surface Preparation of Aluminum A
48、lloysUsing 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 w
49、ater 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). Spray rinse heavy sections as they emerge from the solution asnecessary to prevent staining.STEP 5RINSE (see 7.1.3.2)Rinse for 2 min. minimum in water at 55C (131F) maximumSTEP 6FINAL RINSE (see 7.1.4)Use water from room temperature to 55C (131F) for 1 to 2 min.STEP 7DRY (see 7.1.5)Use air from room temperature to 65C (149F) for not more than 1 h.E8640339.
