1、Designation: F 482 09Standard Practice forCorrosion of Aircraft Metals by Total Immersion inMaintenance Chemicals1This standard is issued under the fixed designation F 482; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the determination of the corrosive-ness of tank-type aircraft maintenance chemicals on aircraft
3、metals and the corrodibility of metals in these maintenancechemicals with time. The determination is made under condi-tions of total immersion by a combination of weight changemeasurements and visual qualitative determinations of change.1.2 The values stated in SI units are to be regarded as thestan
4、dard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica
5、-bility of regulatory limitations prior to use. For specificprecautions, see Section 6.2. Referenced Documents2.1 ASTM Standards:2D 235 Specification for Mineral Spirits (Petroleum Spirits)(Hydrocarbon Dry Cleaning Solvent)D 329 Specification for AcetoneD 1193 Specification for Reagent WaterE1 Speci
6、fication for ASTM Liquid-in-Glass Thermometers3. Significance and Use3.1 This practice not only provides information on theaccumulated effects of corrosion at specific time periods undera given set of conditions, but also provides information on theinitial rate of corrosion of virgin metal, the corr
7、osion rate ofmetal per unit time after long exposure, and the initialcorrosion rate of virgin metal after long exposure of thecorroding fluid to metal. The test also provides a means ofdetermining the direction corrosion will take with time, al-though causes for increase or decrease in the corrosive
8、ness andcorrodibility of media and metal (such as passive film forma-tion or destruction, depletion of corrosive contaminate, and soforth) as a function of time are not given.4. Apparatus4.1 Wide-Mouth Glass Jar or Flask of suitable sizes (3000to 4000 mL), capable of accommodating a reflux condenser
9、, athermometer, and a specimen support system. Fig. 1 shows atypical arrangement, but any array meeting the provisions of4.2-4.5 is acceptable.4.1.1 If agitation is required, use an apparatus capable ofaccepting a stirring mechanism, such as a magnetic stirrer orimpeller. Choose the glass jar or fla
10、sk such that the specimenswill remain fully immersed in a vertical position during thetest, and the ratio of area of immersed metal to volume ofsolution will be in accordance with 9.1.4.2 Specimen-Supporting Devicea glass or fluorocarbonplastic supporting system designed to keep the specimen fullyim
11、mersed while assuring free contact with the corrodingsolution, and designed to physically isolate the specimens fromeach other.4.3 Condensera glass reflux condenser of the water-cooled type, having a condenser jacket 200 to 300 mm inlength.4.4 Constant-Temperature DeviceUse any suitable regu-lated h
12、eating device (mantle, hot plate, or bath) to maintain thesolution at the required temperature.4.5 Thermometeran ASTM 75-mm (3-in.) immersionthermometer having a range from 18 to 150C (0 to 302F)and conforming to requirements for Thermometer 1F in accor-dance with Specification E1.5. Reagents and Ma
13、terials5.1 Mineral Spirits (Petroleum Spirits) (Hydrocarbon DryCleaning Solvent, conforming to Specification D 235.5.2 Methyl n-propyl ketone (MPK).35.3 Acetone, conforming to Specification D 329.1This practice is under the jurisdiction of ASTM Committee F07 on Aerospaceand Aircraft and is the direc
14、t responsibility of Subcommittee F07.07 on Qualifica-tion Testing of Aircraft Cleaning Materials.Current edition approved May 15, 2009. Published June 2009. Originallypublished in 1977. Last previous edition approved in 2003 as F 482 03.2For referenced ASTM standards, visit the ASTM website, www.ast
15、m.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.3The sole source of supply of Methyl n-Propyl Ketone (MPK) known to thecommittee at this time is Eastman Chemical Company, K
16、ingsport, TN, USA. If youare aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.1Copyright ASTM International, 100 Barr Harbor Dri
17、ve, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.4 Reagent Water, conforming to Specification D 1193.6. Safety Precautions6.1 The solvents used in the cleaning of test specimens areflammable and harmful if inhaled. Keep away from sparks andopen flames.Avoid breathing vapors and pro
18、longed or repeatedcontact with the skin. Use with adequate ventilation.6.2 Flammable solvents, acids, or alkalis, or other toxiccompounds are occasionally found in the material used foraircraft maintenance. Take suitable precautions to preventpersonnel injury.7. Test Specimens7.1 The test specimens
19、of a given alloy shall be taken fromthe same sheet stock and shall measure 50.8 by 25.4 by 1.6 mm(2 by 1 by 0.06 in.) with a 3.2-mm (0.125-in.) diametermounting hole suitably located at one end of the specimen.Testat least two and preferably three replicates in each concentra-tion of maintenance che
20、mical solution in accordance with 9.2.The total area of the specimen shall be taken as 28.2 cm2(4.4in.2).8. Test Specimen8.1 Preheat the test specimens to 60 6 2C (150 6 5F) andimmerse in a beaker containing Mineral Spirits, Type II,conforming to Specification D 235. Swab the surface of theindividua
21、l specimen thoroughly using clean forceps to hold thespecimen and the cotton swab.8.2 Shake off the excess solvent. Transfer and immerse thetest specimens separately several times in a beaker of methyln-propyl ketone.8.3 Shake off excess methyl n-propyl ketone and dry in avacuum desiccator or in a l
22、ow temperature oven at 37.7 6 3C(100 6 5F) for 15 min.9. Conditioning9.1 Volume of SolutionThe volume of solution shall be500 mL per specimen. Use fresh solution for each set ofreplicates.9.2 Solution Concentration:9.2.1 Unless otherwise specified, test the specimens insolutions of the maintenance c
23、hemical in the concentratedas-received condition and at the recommended dilution usingdistilled or deionized water conforming to SpecificationD 1193, Type IV. (For solid materials, concentrated conditionshall mean in a saturated solution of the solid material.) In casethe material is not soluble to
24、the extent noted, record this factand continue with the test.9.2.2 Test diphase materials with an appropriate amount ofeach phase loaded into the test vessel to simulate use condi-tions. Totally immerse the corrosion specimens in the workingphase of the maintenance chemical.9.2.3 If water is not use
25、d as the diluent, record the type andspecification of diluent used in the test.9.3 TemperatureUnless otherwise specified, the tempera-ture shall be 37.7 6 3C (100 6 2F).9.4 Test DurationTotal test duration shall be 168 h, withspecimens being added or removed at intermediate intervals.9.5 If the main
26、tenance chemical is to be used with agitation,also test the specimens with appropriate agitation to simulateuse conditions.10. Procedure10.1 Weigh four of five specimens (S1, S2, S3, and S4) of thesame alloy to the nearest 0.1 mg. Record the weights S1W1,S2W1, S3W1, S4W1. Retain the fifth specimen o
27、f each alloy forcomparison purposes.10.2 Immerse three of the specimens (S1, S2, and S3)inthetest solution using only specimens of the same alloy in thecontaining vessel. Retain S4for use in accordance with 10.5.10.3 At the end of 48-h exposure time, remove S1andproceed as follows:10.3.1 Rinse thoro
28、ughly under hot tap water, 49 to 60C(120 to 140F), while scrubbing with a stiff bristle brush.A = CondenserB = Stirring mechanismC = Containing vesselD = Specimen holderE = ThermometerF = Metal specimenG = Maintenance chemical solutionNOTETHIS IS ONE FORM THAT THE EQUIPMENT CAN TAKE, AND IS NOTMANDA
29、TORY.ANY ARRAY MEETING THE REQUIREMENTS OF 4.2-4.5 IS ACCEPTABLE.FIG. 1 Test ApparatusF482092Follow with distilled or deionized water conforming to Speci-fication D 1193, Type IV at room temperature.10.3.2 Rinse with a stream of acetone conforming to Speci-fication D 329 from a wash bottle and dry.1
30、0.3.3 If corrosion deposits are still adhered, remove corro-sion products in accordance withAnnexA1 andAnnexA2 andrinse dry in accordance with 10.3.1 and 10.3.2.10.3.4 Weigh to the nearest 0.1 mg and record as S1W2.Ifthe specimen has been treated in accordance with Annex A1and Annex A2, subtract any
31、 weight losses of the controlspecimen of Annex A1 and Annex A2 from the weight loss ofthe specimen.10.3.5 Calculate the weight loss of the panel as WL.S1= S1W1 S1W2.10.4 At the end of 120-h exposure time, remove S2andproceed in accordance with 10.3. Record the weight loss asS2W2.10.5 Also at the end
32、 of 120-h exposure time, add S4to thereaction vessel.10.6 At the end of 168-h exposure time, remove S3and S4from the solution and proceed as follows:10.6.1 Proceed in accordance with 10.3 for S4and recordthe weight loss as S4W2.10.6.2 For S3, rinse in accordance with 10.3.1 and 10.3.2,then examine f
33、or and record the following visible changes incomparison with the fifth virgin specimen:10.6.2.1 Discoloration and dulling,10.6.2.2 Etching,10.6.2.3 Presence of accretions and relative amounts,10.6.2.4 Pitting, and10.6.2.5 Presence of selective or localized attack.10.6.3 If any corrosion deposits re
34、main, remove these prod-ucts from S3in accordance with Annex A1 and Annex A2.Rinse with distilled water conforming to Specification D 1193,Type IV followed by acetone conforming to SpecificationD 329 and dry.10.6.4 Weigh to the nearest 0.1 mg and calculate the weightloss as W3. If the specimen has b
35、een treated in accordance withAnnex A1 and Annex A2, subtract any weight losses of thecontrol specimen ofAnnexA1 andAnnexA2, from the weightloss of the test specimen.11. Report11.1 Report the following data for each test performed:11.1.1 Name and type of maintenance chemical tested.11.1.2 Concentrat
36、ions, diluent used, and other conditions oftest peculiar to maintenance chemical type.11.1.3 Alloy type, surface treatment and condition, andnumber of specimens tested.11.1.4 Temperature, duration of test, and agitation if any.11.1.5 Average corrosion rate, R1, R2, R3, R4, or weight lossin milligram
37、s per square centimetre per day for each specimenwhere:R5W/surface area of panel in cm2total exposure time of panel/2411.1.6 Range in weight losses.11.1.7 Effect of time on liquid corrosiveness and metalcorrodibility calculated in accordance with Annex A3.11.1.8 Appearance before and after removal o
38、f corrosionproducts with regard to the following:11.1.8.1 Discoloration and dulling,11.1.8.2 Etching,11.1.8.3 Presence of accretions and relative amounts,11.1.8.4 Pitting, and11.1.8.5 Presence of selective or localized attack.12. Keywords12.1 aircraft metals; corrosion rates as weight loss persurfac
39、e unit divided by exposure time per day; in concentrate;in use dilution; liquid corrosiveness; metal corrodibility; tank-type chemicals; temperature control; time control; total immer-sion corrosion; visual corrosive deteriorationANNEXES(Mandatory Information)A1. CHEMICAL METHODS FOR CLEANING CORROD
40、ED SPECIMENSA1.1 After scrubbing to remove loosely attached corrosionproducts, treat the specimens as follows. A blank metalspecimen shall be run at the same time to ensure weight lossesincurred by cleaning the corroded specimens are not includedin the weight loss determination.A1.1.1 Aluminum and I
41、ts AlloysImmerse the specimenfor 5 min in a water solution containing 2 weight % of chromicacid and orthophosphoric acid (85 %) maintained at 79 6 3C(175 6 5F). Rinse in water to remove acid and brush with stiffbristle brush to remove loosened materials.A1.1.2 Copper and Nickel AlloysImmerse the spe
42、cimenfor 2 to 3 min in hydrochloric acid (1 + 1) or sulfuric acid(1 + 10) at room temperature. Scrub with a bristle brush underrunning water and dry.A1.1.3 Magnesium AlloysImmerse the specimen for 1min in chromic acid (20 weight %) to which has been added,with agitation, 1 weight % of silver nitrate
43、 in solution form.Operate the bath at 93 to 100C (200 to 212F).A1.1.4 Iron and SteelImmerse the specimen for 2 to 3min in a boiling solution of ammonium citrate (10 weight %).A1.1.5 Stainless SteelImmerse the specimen for 5 min ina solution of nitric acid (30 volume %) at a temperature of 49to 54C (
44、120 to 130F).F482093A2. METHOD FOR ELECTROLYTIC CLEANING OF CORROSION TEST SPECIMENS AFTER EXPOSUREA2.1 This method is known to be suitable for the metalsand alloys listed in Table A2.1; other metals or alloys must beevaluated before use.A2.2 After scrubbing, remove loosely attached corrosionproduct
45、s. Treat the specimen as a cathode in hot, dilutedsulfuric acid under the following condition:Test solution sulfuric acid (5 weight %)Inhibitor 2 mL organic inhibitor/litre of solutionAnode carbonCathode test specimenCathode current density 20 A/dm2(6.5 A/0.325 dm2)Temperature 74C (165F)Exposure per
46、iod 3 minA2.3 After the electrolytic treatment, scrub the specimens,while wet, with a stiff bristle brush. Run a blank metalspecimen at the same time to ensure weight losses incurred bycleaning the corroded specimens are not included in the weightloss determination.A2.4 Note the possible redepositio
47、n of adherent metal fromreducible corrosion products (and thus lowering the apparentweight loss) resulting from this electrolytic treatment. How-ever, general experience has indicated that in most cases ofcorrosion in liquids, the possible errors from this source are notlikely to be serious. Use eit
48、her 2 mL of any proprietaryinhibitor or about 0.5 g/L of such inhibitors as diorthotolylthiourea, quinoline ethiodide, or beta-naphthol quinoline.A3. CRITERIA FOR CORROSIVENESS OF ENVIRONMENT AND METAL CORRODIBILITYA3.1 The corrosion results obtained by this method pro-vides information on the corro
49、siveness of the environment andthe corrodibility of the material under test in the environment.Therefore, R1is the initial corrosion rate of virgin metal perunit time, R5is the corrosion rate of metal per unit time afterlong exposure, and R4is the corrosion rate of virgin metal afterlong exposure of the corroding fluid to corroding metal. Thesignificance of these values can be appreciated by comparingthe corrosion rate R1for a unit time interval of 0 to 48 h withthe corrosion rate for the unit time interval of 120 to 168 h,which shows the magnitude a
