1、 METRIC MIL-STD-1503C (USAF) 01 March 2007 SUPERSEDING MIL-STD-1503B 13 November 1989 DEPARTMENT OF DEFENSE STANDARD PRACTICE PREPARATION OF ALUMINUM ALLOYS FOR SURFACE TREATMENT AND INORGANIC COATING This document is inactive for new design. AMSC N/A AREA: MFP Provided by IHSNot for ResaleNo reprod
2、uction or networking permitted without license from IHS-,-,-MIL-STD-1503C FOREWORD 1. This Military Standard is approved for use by the 309MXSG/MXRL, Department of the Air Force and is available for use by all Departments and Agencies of the Department of Defense. 2. This standard provides guidance
3、on the procedures for preparation of aluminum alloys for surface treatments and inorganic coating for the Air Force repair process, acquisition and manufacture of parts and/or spare parts on landing gear of all military aircraft. 3. Beneficial comments, recommendations, additions, deletions, clarifi
4、cations, etc. and any data that may improve this document should be sent to: 309MXSG/MXRL, Hill AFB, UT 84056-2609 or e-mailed to: 309MXSG/MXRLhill.af.mil. Since contact information can change, verification of currency of this address information through ASSIST Online database at http:/assist.daps.d
5、la.mil. ii Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1503C CONTENTS PARAGRAPHS PAGEFOREWORD i 1. SCOPE 1 1.1 Scope 1.2 Classification 1 1.2.1 Surface Cleaning 1.2.2 Surface Preparation 1 1.2.3 Preparation for Plating 2. APPLICABLE DOCUM
6、ENTS 1 2.1 General 2.2 Government Documents 1 2.2.1 Specifications, Standards and Handbooks 1 2.3 Non-Government Documents 2 2.4 Order of Precedence 3. DEFINITIONS (Not applicable) 2 4. GENERAL REQUIREMENTS 2 4.1 Materials and Equipment 4.1.1 Materials 2 4.1.2 Equipment 3 4.2 Racking 4 4.3 Masking 4
7、.4 Handling of Parts 4 4.5 Finish 4.6 Re-processing 4 5. DETAILED REQUIREMENTS 4 5.1 Surface Cleaning 5.1.1 Alkaline Cleaners 4 5.1.2 Alkaline Etch 5.1.3 Smut Removal 5 5.2 Surface Preparation for Anodizing/Conversion Coating 6 5.3 Surface Preparation for Plating 6 5.4 Quality Control 8 5.4.1 Qualit
8、y Control Responsibility 5.4.2 Process Controls 8 5.4.3 Adhesion 5.4.4 Castings 8 5.4.5 Caution (or Warning) iii Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1503C CONTENTS PARAGRAPHS PAGE6. NOTES 8 6.1 Intended use 6.2 Subject term (key w
9、ord) listing 8 6.3 Changes from previous issue 9 CONCLUDING MATERIAL 9 iv Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1503C 1. SCOPE 1.1 This standard describes the cleaning, activation and under-plating process, and material required for
10、 aluminum and aluminum alloys prior to applying inorganic coatings. It is intended that this standard be used in conjunction with other process documents, where the technical requirements are for the application of surface treatments and inorganic coatings on aluminum and aluminum alloys. 1.2 Classi
11、fication. This standard covers the following cleaning methods and surface pre-treatment process. 1.2.1 Surface Cleaning. Clean surface in accordance with paragraph 5.1. 1.2.2 Surface Preparation. Prepare surface for anodizing and conversion coating in accordance with paragraph 5.2. 1.2.3 Preparation
12、 for Plating. Prepare for plating in accordance with paragraph 5.3. 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are specified throughout this document. While every effort has been made to ensure the completeness of this list, document users are cautioned that they must
13、meet all specified requirements of the documents cited, whether or not they are listed. 2.2 Government Documents.2.2.1 Specifications, standards, and handbooks. The following specifications, standards, handbooks and commercial item descriptions form a part of this document to the extent specified he
14、rein. Unless otherwise specified the issues of these documents are those cited in the solicitation or contract. COMMERCIAL ITEM DESCRIPTIONS: A-A-55827 Chromium Trioxide, Technical A-A-55828 Sulfuric Acid, Technical A-A-59105 Nitric Acid, Technical A-A-59563 Sodium Carbonate, Anhydrous, Technical A-
15、A-59456 Ferric Chloride, Anhydrous, Crystalline, Technical DEPARTMENT OF DEFENSE SPECIFICATIONS: MIL-Z- 291 Zinc Oxide, Technical (Inactive) MIL-A- 24641 Acid Hydrofluoric, Technical 1 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1503C DEP
16、ARTMENT OF DEFENSE STANDARDS: MIL-STD-871 Electro-Chemical Stripping of Inorganic Finishes (Inactive) MIL-STD-1504 Abrasive Blasting (Inactive) (Copies of these documents are available online at http:/assist.daps.dla.mil.online/start/ or from the Standardization Document Order Desk, 700 Robbins Aven
17、ue, Building 4D, Philadelphia, PA 19111-5094.) 2.3 Non-Government Documents. The following documents form a part of this standard to the extent specified herein. Unless otherwise indicated, these issues of these documents are those cited in the solicitation or contract. AMERICAN SOCIETY FOR TESTING
18、AND MATERIALS (ASTM) ASTM D456 Caustic Soda, Anhydrous ASTM D537 Standard Specification for Sodium Metasilicate (Copies of these documents are available at www.astm.org or ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959.) 2.4 Order of Precedence. In the eve
19、nt of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document; however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. DEFINITIONS Not applicable. 4. GENERAL REQUI
20、REMENTS 4.1 Materials and Equipment.4.1.1 Materials. Materials used in preparing aluminum alloys for surface treatments and inorganic coating: a. Ammonium Biflouride b. Chromium Trioxide (A-A-55827) c. Copper Cyanide d. Ferric Chloride (A-A-59456) e. Hydrofluoric Acid (MIL-A-24641) f. Nitric Acid (A
21、-A-59105) 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1503C g. Rochelle Salt h. Sodium Bisulfate i. Sodium Carbonate (A-A-59363) j. Sodium Cyanide k. Sodium Fluorosilicate l. Sodium Gluconate m. Sodium Hydroxide (ASTM D456) n. Sodium Me
22、t silicate (ASTM D537) o. Sulphuric Acid (A-A-55828) p. Trisodium Phosphate q. Zinc Oxide (MIL-Z-291 Inactive) 4.1.2 Equipment. a. Power Source. Either generated or rectified D.C. current may be used. Ripple value shall not exceed 10 percent as measured by dividing the root mean square of the A.C. v
23、oltage component by the D.C. voltage. This can be measured by using RMS A.C. voltage meter and dividing this value by the D.C. voltage. These requirements are to be taken across the anode and cathode bus at the tank. b. Tanks. Tanks should be resistant to the operating temperature and the chemical e
24、nvironment. Tanks in which any electrolytic action takes place must be free of short circuits. c. Temperature Control. Plating tanks to be operated at temperature other than room temperature shall be equipped with automatic temperature indicating and regulating devices. d. Instrumentation. An ammete
25、r shall be place in series with the plating tank cathode. The ammeter shall have sufficient shunts and switches to provide a full-scale reading equal to the maximum capacity of the power source, and an accuracy of plus or minus 10 percent of the current being measured. e. Blast Equipment. A blast ca
26、binet shall be located near the finishing line. Size of the cabinet shall be adequate to enclose the parts to be finished. Air lines shall be suitably trapped and filtered to prevent in-process contamination of the parts to be cleaned. 3 Provided by IHSNot for ResaleNo reproduction or networking per
27、mitted without license from IHS-,-,-MIL-STD-1503C f. Bake Oven. A bake oven, if required, shall be located near the finishing line. The size of the oven shall be adequate to enclose the part to be finished. The oven shall be equipped with temperature indicating and regulating devices. 4.2 Racking. S
28、ufficient contact area and pressure shall be provided to carry the current without overheating. Racking should be performed at the most convenient step prior to plating. 4.3. Masking. Sections or areas of the part that are not to be finished will be masked off. Plug and masking materials, which do n
29、ot contaminate the finishing bath shall be used. Masking should be performed at the most convenient step prior to finishing. 4.4 Handling of Parts. After the parts have been cleaned, they will be handled in such a manner; white gloves, etc, that will ensure a minimum of contamination. 4.5 Finish. Th
30、e finish of the part shall be controlled by the application specification. 4.6 Re-processing. Parts rejected for defective finish and require stripping and re-coating, shall include all the steps of this specification. Parts shall be stripped in accordance with MIL-STD-871. 5. DETAILED REQUIREMENTS
31、5.1 Surface Cleaning.5.1.1 Alkaline Cleaners. Alkaline clean in one of the following solutions or equivalent. 5.1.1.1 Alkaline Cleaner Number 1:a. Sodium Hydroxide 3.75 11.25 g/l (3 5 oz/gal) b. Trisodium Phosphate 7.5 22.5 g/l (1 3 oz/gal) c. Sodium Metasilicate 22.5 37.5 g/l (3 5 oz/gal) d. Temper
32、ature 52 - 57C (125 - 135F) e. Time one to two (1 to 2) minutes 5.1.1.2 Alkaline Cleaner Number 2:a. Trisodium Phosphate 22.5 37.5 g/l (3 5 oz/gal) b. Sodium Carbonate 7.5 22.5 g/l (1 3 oz/gal) c. Temperature 52 57C (125 135F) d. Time one to two (1 2) minutes 4 Provided by IHSNot for ResaleNo reprod
33、uction or networking permitted without license from IHS-,-,-MIL-STD-1503C 5.1.2 Alkaline Etch. Remove scale, corrosion, carbon, etc in the following inhibited alkaline etch or equivalent: 5.1.2.1 Etching Solution.a. Sodium Hydroxide 3.75 11.25 g/l (0.5 1.5 oz/gal) b. Trisodium Phosphate 30.0 90.0 g/
34、l (4 12 oz/gal) c. Sodium Carbonate 7.5 45.0 g/l (1 6 oz/gal) d. Sodium Gluconate 22.5 g/l (30.0 oz/gal) minimum e. Temperature 52 - 57C (125 135F) f. Time two (2) minutes maximum 5.1.3 Smut Removal. Remove smut in the following solutions or equivalent: 5.1.3.1 De-Smut Number 1:a. Nitric Acid 60 80%
35、 by volume b. Hydrofluoric Acid 15 20% by volume c, Temperature ambient d. Time 30 seconds approximately 5.1.3.2 De-Smut Number 2:a. Nitric Acid 40 60% by volume b. Temperature ambient c. Time 30 seconds approximately 5.1.3.3 De-Smut Number 3:a. Nitric Acid 40-60% by volume b. Sulphuric Acid 20 30%
36、by volume c. Ammonium Biflouride 105 135 g/l (14 18 oz/gal) d. Temperature ambient e. Time 30 seconds approximately 5.1.3.4 De-Smut Number 4:5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1503C a. Chromic Acid 4.5 7.5 g/l (0.7 l.0 oz/gal)
37、b. Sodium Bisulfate 120 128 g/l (16 17 oz/gal) c. Sodium Fluorosilicate 7.5 10 g/l (1.0 1.25 oz/gal) d. Temperature ambient e. Time 10 15 minutes 5.2 Surface Preparation for Anodizing/Conversion Coating: a. Step Number 1: Vapor Degrease. b. Step Number 2: Alkaline Clean. c. Step Number 3: Rinse thor
38、oughly in clean water. The rinse water temperature should be ambient. d. Step Number 4: (Optional) Alkaline Etch. e. Step Number 5: (Omit if Step 4 was not performed.) Rinse thoroughly in clean water. The rinse water temperature should be ambient. f. Step Number 6: Remover Smut. g. Step Number 7: Ri
39、nse thoroughly in clean water. The rinse water temperature should be ambient. h. Step Number 8: Anodize or conversion cost immediately. 5.3 Surface Preparation for Plating.a. Step Number 1: Parts shall be vapor degreased. No minimum elapsed time shall elapse between this operation and the cleaning o
40、peration. b. Step Number 2: Clean by abrasive blasting per MIL-STD-1504; using 60 180 grit aluminum oxide, vapor blast or garnet abrasive blast. Elapsed time between this step and step number 3 should not to exceed sixty (60) minutes. c. Step Number 3: Alkaline clean. d. Step Number 4: Rinse thoroug
41、hly in clean water. The rinse water temperature should be ambient. e. Step Number 5: Remove smut. f. Step Number 6: Rinse thoroughly in clean water. The rinse water temperature should be ambient. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-
42、STD-1503C g. Step Number 7: Zinc immersion plate with moderate part agitation in the following solution: Sodium Hydroxide 450 525 g/l (60 70 oz/gal) Zinc Oxide 75 97.5 g/l (10 13 oz/gal) Ferric Chloride Hex hydrate 0.75 0.97 g/l (0.10 0.13 oz/gal) Rochelle salt 7.5 9.75 g/l (1.0 1.3 oz/gal) Temperat
43、ure 21 27 C (70 - 80F) Time 30 60 seconds h. Step Number 8: Rinse thoroughly in clean water. The rinse water temperature should be ambient. i. Step Number 9: Remove zincates using solution 4.1.3.2 (De Smut Number 2) or equivalent. j. Step Number 10: Rinse thoroughly in clean water. The rinse water t
44、emperature should be ambient. k. Step Number 11: Zinc immersion plate in the zinc immersion solution, paragraph 5.3.7 for 30 40 seconds. It is essential that the immersion time in the zincates solution be closely controlled to prevent formation of an extremely heavy coating. The proper coating will
45、be smooth and continuous and in some cases, can be achieved without the use of Step Number 7 through 10. Repeat step number 7 through 10 until the desired coating is obtained. l. Step Number 12: Rinse thoroughly in clear water. The rinse water temperature should be ambient. m. Step Number 13: (Optio
46、nal) Copper strike at 2.5A/dm2(24A/ft2) for approximately 3 minutes, then reduce the current to 1.25A/dm2(12A/ft2) for 10 to 15 minutes. Apply voltage so that current will flow upon the immersion of parts. Copper strike in the following solution: Copper Cyanide 37.5 45 g/l (5 6 oz/gal) Sodium Cyanid
47、e 45 52.5 g/l (6 7 oz/gal) Sodium Carbonate 30 60 g/l (4 8 oz/gal) Rochelle Salt 30 60 g/l (4 8 oz/gal) Free Sodium Cyanide 1.3 3.75 g/l (0.2 0.5 oz/gal) Temperature 38 - 54C (100 - 130F) 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1503C N
