1、MIL-DTL-83488D1 April 1999SUPERSEDINGMIL-C-83488C1 May 1985DETAIL SPECIFICATIONCOATING, ALUMINUM, HIGH PURITYThis specification is approved for use by all Departments and Agenciesof the Department of Defense1. SCOPE1.1 Scope . This specification establishes the requirements for coating low alloy ste
2、el, stainlesssteel, aluminum alloy, copper alloy, and titanium alloy parts with high purity aluminum (99percent plus) (see 6.1).1.2 Classification . High Purity aluminum coatings should be of the following classes andtypes (see 6.1.1, 6.1.2).1.2.1 Classes.Class 1 - 0.0010 inch thick (0.026 mm) (min)
3、Class 2 - 0.0005 inch thick (0.013 mm) (min)Class 3 - 0.0003 inch thick (0.008 mm) (min)1.2.2 Types.Type I - as coatedType II - with supplementary chromate treatment (see 3.4)Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be ofuse in improving this docum
4、ent should be addressed to: ASC/ENSI, 2530 Loop Rd West, Wright-Patterson AFB OH 45433-7101, by using the self-addressed Standardization Document ImprovementProposal (DoD Form 1426) appearing at the end of this document or by letter .AMSC N/A AREA MFFPDISTRIBUTION STATEMENT A . Approved for public r
5、elease; distribution is unlimited.INCH-POUNDProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-83488D22. APPLICABLE DOCUMENTS2.1 General . The documents listed in this section are specified in sections 3 and 4 of thisspecification. This section
6、does not include documents cited in other sections of this specificationor recommended for additional information or as examples. While every effort has been made toensure the completeness of this list, document users are cautioned that they must meet allspecified requirement documents cited in sect
7、ions 3 and 4 of this specification whether or not theyare listed.2.2 Government documents2.2.1 Specifications and standards. The following specifications and standards form a part ofthis document to the extent specified herein. Unless otherwise specified, the issues of thesedocuments are those liste
8、d in the issue of the Department of Defense Index of Specifications andStandards (DoDISS) and supplement thereto, cited in the solicitation (see 6.2).SPECIFICATIONSDEPARTMENT OF DEFENSEMIL-S-5002 Surface Treatments and Inorganic Coatings for MetalSurfaces of Weapon SystemsMIL-C-5541 Chemical Convers
9、ion Coating on Aluminum andAluminum AlloysMIL-T-9046 Titanium and Titanium Alloy, Steel, Strip and Plate(Unless otherwise indicated, copies of federal and military specifications, standards, andhandbooks are available from the Defense Printing Service Detachment Office, 700 RobbinsAvenue, Building 4
10、D, and Philadelphia, PA 19111-5094).2.3 Non-Government publications. The following documents form a part of this documentto the extent specified herein. Unless otherwise specified, the issues of the documents that areDoD adopted are those listed in the issue of DoDISS cited in the solicitation. Unle
11、ss otherwisespecified, the issues of documents not listed in the DoDISS are the issues of the documents citedin the solicitation (see 6.2).Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-83488D3AMERICAN SOCIETY FOR TESTING AND MATERIALS STAND
12、ARDSASTM E18 Rockwell Hardness and Rockwell Superficial Hardness ofMetallic MaterialsASTM B117 Operating Salt Spray (Fog) Apparatus (DoD Adopted)ASTM B487 Measurement of Metal and Oxide Coating, Thickness byMicroscopic Examination of a Cross Section, Method of (DoDAdopted)ASTM B499 Measurement of Co
13、ating Thickness by the Magnetic MethodNonmagnetic Coatings on Magnetic Base Metals (DoDAdopted)ASTM B567 Measurement of Coating Thickness by the Beta BackscatterMethod (DoD Adopted)ASTM E1004 Test Method for Electromagnetic (Eddy-Current)Measurements Of Electrical Conductivity(Application for copies
14、 should be addressed to the American Society for Testing and Materials,100 Barr Harbor Drive, West Conshohocken PA 19428-2959, (610-832-9500)SOCIETY OF AUTOMOTIVE ENGINEERSAMS-QQ-A-250/4 Aluminum Alloy 2024, Plate and SheetAMS-QQ-A-250/12AMS- 6350Aluminum Alloy 7075, Plate and SheetSteel Sheet, Stri
15、p, and Plate 0.95Cr 0.20Mo (0.28 0.33C)(SAE 4130)(Application for copies should be addressed to the Society of Automotive Engineers, 400Commonwealth Drive, Warrendale, PA 15096)2.4 Order of precedence . In the event of a conflict between the text of this document andthe references cited herein, the
16、text of this document takes precedence. Nothing in this document,however, supersedes applicable laws and regulations unless a specific exemption has beenobtained.3. RE QUIREMENTS3.1 Materials . The material shall be capable of conforming to the requirements of thisspecification and in accordance wit
17、h 3.1.1.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-83488D43.1.1 Composition . The composition of the aluminum coating shall not be less than 99.0percent aluminum.3.2 Eq uipment and processes . As specified in 3.9.2, the equipment and pro
18、cesses employedto produce high purity aluminum coatings shall be capable of providing a uniform coating.3.2.1 Processes . The process used to deposit the coating shall not cause a temperature rise inthe parts that could cause adverse reaction between the coating and the substrate or adverselyaffect
19、the substrate.3.2.1.1 Cleaning . All base metals shall be cleaned in accordance with MIL-S-5002 or equivalentcleaning method, prior to coating with high purity aluminum.3.3 Areas of deposit . Except as specified in 3.5.4, the coating shall completely cover allvisible surfaces, including roots of thr
20、eads, and sharp corners. The coating shall be depositeddirectly on the base metal without a preliminary coating of other metal.3.4 Supplementary chromate treatment (Type II) . Unless otherwise specified, the highpurity coating shall be Type II, which is a Type I coating with a supplementary chromate
21、treatment in accordance with MIL-C-5541, Class 1A. Chromate treated parts, other thanfasteners, should receive additional protective coatings. Application requiring electricalconductivity (see 6.1) shall be chromate treated with a MIL-C-5541 solution which meets bothClass 1A (corrosion resistance) a
22、nd Class 3 (low electrical resistance) requirements.3.5 Thickness of coating . Except as specified in 3.5.4, the thickness of high purityaluminum shall be as specified in 1.2.1 on all visible surfaces.3.5.1 Class 1 thickness . Class 1 thickness shall be used where tolerance will permit.3.5.2 Class 2
23、 thickness . Class 2 thickness shall be used where Class 1 thickness isunacceptable for dimensional thickness reasons.3.5.3 Class 3 thickness . Class 3 thickness shall be used for close tolerance applications such asfinely threaded parts.3.5.4 Exceptions to Class 1, 2, and Class 3 thickness . Fixtur
24、e contact points, holes, recesses,internal threads, and other areas where a controlled deposit cannot be obtained shall not besubject to a thickness requirement. However, there shall be visual evidence of coating in holesand recesses down to a depth of at least the diameter of the hole or recess. Fa
25、stener areas thatcannot be touched with a 0.020-inch diameter ball shall not be subject to thickness requirement.Threads that gage undersize solely as a result of coating thickness shall be considered acceptable.3.6 Stripping of aluminum coatings. Steel parts to be recoated shall be stripped bymecha
26、nical means or in a suitable caustic solution. If stripped with caustic solution, steel partshaving hardness Rockwell C-40 or greater shall be baked after stripping at an appropriate timeProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-83488D5
27、and temperature to relieve any hydrogen embrittlement in the base metal. Nonsteel parts shall bestripped by mechanical means or in a suitable chemical solution that does not result in degradationof the base metal.3.7 Adhesion. When tested in accordance with 4.4.2, the adhesion of the coating shall n
28、otshow separation from the base metal at the interface when examined at a minimum magnificationof approximately four-diameters. The interface between the aluminum and the base metal is thesurface of the base metal before coating. The formation of cracks in the deposit caused byrupture of the base me
29、tal but does not result in flaking, peeling or blistering of the deposit shallnot be cause for rejection.3.8 Corrosion resistance . When tested in accordance with 4.4.3, test samples shall show noevidence of corrosion of the base metal after testing as specified in table 1. The appearance ofwhite co
30、rrosion products on the aluminum coating during the test period shall not be cause forrejection.Table 1. Salt Spray TestClass Test Period (hours)Type I Type II1 504 6722 336 5043 168 3363.9 Workmanship3.9.1 Base metal . The base metal shall be free from defects that will be detrimental to theappeara
31、nce or the protective value of the coating.3.9.2 Coating . The high purity aluminum coating shall be smooth, fine grained, adherent,uniform in appearance, free from staining, pitting, and other defects. The coating shall show noindication of contamination or improper operation of equipment used to p
32、roduce the deposit, suchas excessively powdered or darkened coatings. Type II parts processed in accordance withMIL -C -5541 requirements shall have a continuous, distinctly colored protective film ranging incolor from yellow and iridescent bronze through olive drab and brown.3.10 Base metal integri
33、ty. When tested in accordance with 4.4.4, aluminum base metal parts,after coating, shall have a Rockwell B hardness change of no more than 3 points. The hardnessafter coating shall meet the minimum acceptable value for that alloy and temper.Provided by IHSNot for ResaleNo reproduction or networking
34、permitted without license from IHS-,-,-MIL-DTL-83488D64. VERIFICATION4.1 Classification of inspection . The inspection requirements specified herein are classifiedas follows:a. Conformance inspection (see 4.2).4.2 Conformance inspections. Conformance inspections shall include the examination of4.2.1
35、 and the tests of 4.3.1 through 4.4.4.4.2.1 Inspection lot . A lot shall consist of coated samples of approximately the same size,shape, material type, and class of coating, coated in the same production run. In the case of shortproduction runs, a lot for inspection purposes may be made up of a grou
36、p of small lots coveringorders of parts similar in size and shape and coated under similar conditions. Lot size shall notexceed normal production run capability.4.2.1.1 Sample for thickness and adhesion . A random sample of two specimens shall be takenfrom each inspection lot or a minimum of two tes
37、t specimens shall be prepared in accordance with4.3 to represent the inspection lot.4.2.1.2 Sample for corrosion resistance . A random sample of two specimens shall be takenfrom the designated inspection lot at a minimum of once per month or two test specimens shall beprepared in accordance with 4.3
38、 to represent the inspection lot. Failure of any sample shallrequire random sampling for five consecutive inspection lots (see 4.2.1) without failure.4.2.1.3 Sample for base me tal integrity . When the base metal is aluminum, two randomsamples shall be taken from each inspection lot.4.3 Test specime
39、ns . When the coated parts are of such form or material as to not readilyadaptable to a test specified herein, or for destructive tests, or for sampling of small lot sizes, testspecimens shall be tested instead. Test specimens shall be introduced into a lot at regular intervalsat the cleaning operat
40、ion preliminary to the coating and shall not be separated from the lot untilafter completion of the processing. Conditions affecting the coating of the specimens, includingthe spacing and positioning with respect to coating source and to other objects being coated, shallcorrespond as nearly as possi
41、ble to those affecting the significant surfaces of the specimensrepresented.4.3.1 Adhesion test samples4.3.1.1 Steel parts . In accordance with AMS 6350 or equivalent, use metal strips approximately1 inch by 4 inches by 0.040 inch made of 4130 steel for steel parts.4.3.1.2 Titani um parts . In accor
42、dance with MIL-T-9046 or equivalent, use metal stripsapproximately 1 inch by 4 inches by 0.040 inch made of Ti -6Al -4V for titanium parts.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-83488D74.3.1.3 Aluminum or copper parts . In accordance
43、 with AMS-QQ-A-250/4 or equivalent, for2000 series aluminum or copper parts, or 7075-T6 in accordance with AMS-QQ-A-250/12 orequivalent, for 7000-series aluminum parts, use metal strips approximately 1 inch by 4 inches by0.040 inch made of 2024-T81.4.3.2 Thickness test sample . In accordance with AM
44、S 6350 or equivalent, use metal stripsapproximately 1 inch by 4 inches by 0.040 inch made of 4130 steel. Test samples shall be usedonly when the base metal is other than a ferrous alloy.4.3.3 Corrosion test samples. In accordance with AMS 6350 or equivalent, use panels at least3 inches wide by 6 inc
45、hes long by 0.040 inch made of 4130 steel for corrosion tests.4.4 Methods of inspection4.4.1 Thickness . In accordance with 4.2.1.1, test samples shall have the thickness determinedby eddy current test, beta backscatter test, micrometer measurements, microscopic test, ormagnetic tests. The magnetic
46、test is applicable only to ferrous alloy substrates. The betabackscatter test shall be made in accordance with ASTM B567. The microscopic test shall bemade in accordance with ASTM B487. The magnetic test shall be made in accordance withASTM B499. For verification of other test methods, the microscop
47、ic test shall be used. If thethickness of the coating on a nonferrous alloy part cannot suitably be measured with any of thesetest devices, test specimens in accordance with 4.3.2 may be used. Due to coating wraparoundthe coating thickness on the test specimens (4.3.2) is thicker than on the product
48、ion parts. Tocompensate for the wraparound effect the thickness on the production parts is determined bydividing the thickness measured on the test specimens by 1.6.4.4.2 Adhesion . In accordance with 4.2.1.1, test samples shall have adhesion determined bymethods 4.4.2.1 or 4.4.2.2. Test samples for
49、 individual production parts shall be in accordancethe 4.4.2.3. The eddy current test for conductivity measures shall be made in accordance withASTM E1004.4.4.2.1 Nonadhesion. Scrape the surface of the coated article (4.3.1) to expose the base metaland examine at a minimum of four-diameter magnification for evidence of nonadhesion. Anyevidence of nonadhesion from the base metal shall be cause for rejection.4.4
