1、 SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising theref
2、rom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2008 SAE International All rights reserved. No part of this publication ma
3、y be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA)
4、Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org AMS-C-27725C AEROSPACE MATERIAL SPECIFICATION Issued 1999-10 Revised 2008-02 Superseding AMS-C-27725B Coating, Corrosion Preventative, for Aircraft Integral Fuel Tanks for Use to 250 F (121 C) RATIONALE To correct par
5、agraph numbering errors in the B revision. 1. SCOPE 1.1 Form This specification covers three types of corrosion preventative coatings for protection of aircraft integral fuel tanks. 1.2 Application The coating materials covered by this specification are typically applied to the interior of aircraft
6、integral fuel tanks to protect against corrosion from fuel contaminants, but usage is not limited to such applications. They are suitable for use in a service temperature range from -65 to +250 F (-54 to +121 C). 1.3 Classification The corrosion-preventative coatings covered by this specification sh
7、all be of the following types. Type 1 - A two-component polyurethane coating with less than 420 g/l Volatile Organic Compound (V.O.C.) content. Type 2 - A two-component polyurethane coating with less than 720 g/l V.O.C. content. Type 3 - Non-chromated coating with less than 420 g/l V.O.C. content 1.
8、4 Safety - Hazardous Materials While the materials, methods, applications, and processes described or referenced in this specification may involve the use of hazardous materials, this specification does not address the hazards which may be involved in such use. It is the sole responsibility of the u
9、ser to ensure familiarity with the safe and proper use of any hazardous materials and to take necessary precautionary measures to ensure the health and safety of all personnel involved. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking perm
10、itted without license from IHS-,-,-SAE AMS-C-27725C - 2 - 2. APPLICABLE DOCUMENTS The issue of the following documents in effect on the date of the purchase order forms a part of this specification to the extent specified herein. The supplier may work to a subsequent revision of a document unless a
11、specific document issue is specified. When the referenced document has been cancelled and no superseding document has been specified, the last published issue of that document shall apply. 2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel:
12、877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. AMS 2471 Anodic Treatment of Aluminum Alloys, Sulfuric Acid Process, Undyed Coating AMS 2473 Chemical Film Treatment for Aluminum Alloys General Purpose Coating AMS 2629 Fluid, Jet Reference AMS 2825 Material Safety Dat
13、a Sheets AMS 3276 Sealing Compound, Integral Fuel Tanks and General Purpose, Intermittent Use to 360 F (182 C) AMS 3819 Cloths, Cleaning, for Aircraft Primary and Secondary Structural Surfaces AMS 4045 Aluminum Alloy Sheet and Plate, 5.6Zn - 2.5Mg - 1.6Cu - 0.23Cr (7075; -T6 Sheet, -T651 Plate) Solu
14、tion and Precipitation Heat Treated AS5505 Requirements for Accreditation of Testing Laboratories for Organic Coatings AS9100 Quality Systems - Aerospace - Requirements ARP1917 Clarification of Terms Used in Aerospace Metals Specifications 2.2 PRI Publications Available from Performance Review Insti
15、tute, 161 Thorn Hill Road, Warrendale, PA 15086-7527, Tel: 724-772-1616, www.pri-network.org. PRI QPL-AMS-C-27725 Products Qualified Under AMS-C-27725 PD 2000 Procedures for an Industry Qualified Product Management Process 2.3 ASTM Publications Available from ASTM International, 100 Barr Harbor Driv
16、e, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM B 36 Brass Plate, Sheet, Strip and Rolled Bar ASTM D 257 DC Resistance or Conductance of Insulating Materials ASTM D 740 Standard Specification for Methyl Ethyl Ketone ASTM D 1200 Viscosity by Ford Viscosity Cu
17、p ASTM D 1353 Nonvolatile Material in Volatile Solvents for Use in Paint, Varnish, Lacquer and Related Products ASTM D 1475 Density of Liquid Coatings, Inks, and Related Products ASTM D 1974 Methods of Closing, Sealing, and Reinforcing Fiberboard Boxes ASTM D 3960 Volatile Organic Compound (VOC) Con
18、tent of Paint and Related Coatings ASTM D 3335 Standard Test Method for Low Concentrations of Lead, Cadmium, and Cobalt in Paint by Atomic Absorption Spectroscopy ASTM D 3363 Standard Test Method for Film Hardness by Pencil Test Copyright SAE International Provided by IHS under license with SAENot f
19、or ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AMS-C-27725C - 3 - 2.4 U.S. Government Publications Available from the Document Automation and Production Service (DAPS), Building 4/D, 700 Robbins Avenue, Philadelphia, PA 19111-5094, Tel: 215-697-6257, http:/assist.d
20、aps.dla.mil/quicksearch/. PPP-C-96 Can, Metal, 28 Gage and Lighter FED-STD-791 Lubricants, Liquid Fuels, and Related Products, Methods of Testing MIL-PRF-23699 Lubricating Oil, Aircraft Turbine Engine, Synthetic Base, NATO Code 0-156 MIL-PRF-83282 Hydraulic Fluid, Fire Resistant, Synthetic Hydrocarb
21、on Base, Aircraft MIL-DTL-85470 Inhibitor, Icing, Fuel System, High Flash NATO Cold Number S-1745 MIL-A-8625 Anodic Coatings for Aluminum and Aluminum Alloys MIL-DTL-5541 Chemical Conversion Coatings on Aluminum and Aluminum Alloys 2.5 ISO Publications Available from American National Standards Inst
22、itute, 25 West 43rd Street, New York, NY 10036, Tel: 212-642-4900, www.ansi.org. ISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories 3. TECHNICAL REQUIREMENTS 3.1 Materials The basic ingredient shall be polyurethane for Types 1 and 2 with curing agents, thin
23、ners, and additives suitable for various application methods including brushing, dipping, and spraying. Type 3 shall not contain any chromium or chromium compounds. Incidental chromium content in Type 3 coatings shall not exceed 5 ppm. The basic ingredients for the Type 3 coatings are not specified,
24、 providing the material will meet the performance requirements set forth in this specification and is suitable for various application methods including brushing, dipping, and spraying. All three types of coatings, when tested in accordance with ASTM D 3335, shall not contain any cadmium or cadmium
25、compounds and shall not contain more than 0.06 percent of lead. 3.2 Properties The coating, when prepared in accordance with the manufacturers instructions shall conform to the requirements shown in Table 1, determined in accordance with specified test methods in Table 1. Copyright SAE International
26、 Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AMS-C-27725C - 4 - TABLE 1 - APPLICATION PROPERTIES Paragraph Property RequirementType 1 Requirement Type 2 Requirement Type 3 Test Method 3.2.1 Surface appearance Smooth, un
27、iform, and free of film porosity and irregularities Smooth, uniform, and free of film porosity and irregularities Smooth, uniform, and free of film porosity and irregularities 4.6.5.1 3.2.2 Density, variation from acceptable qualification sample listed on QPL, percent 5 5 5 4.6.5.2 3.2.3 Volatile Or
28、ganic Compound Content (VOC) g/l, max 420 720 420 4.6.5.3 3.2.4 Viscosity, seconds Initial After Application Life 13 to 23 35 10 to 20 20 13 to 23 35 4.6.5.4 4.6.5.4 3.2.5 Application life, hours, min 4 4 4 4.6.5.5 3.2.6 Drying time, hours max at standard conditions 2 2 2 4.6.5.6 3.2.7 Coating shall
29、 be fully cured within 21 days at standard conditions for Types 1 and 3, and within 14 days at standard conditions for Type 2. Types 1, 2, and 3 shall also be fully cured within 24 hours at standard conditions followed by 24 hours at 140 F 2 (60 C 1) and 50 percent 5 relative humidity when tested in
30、 accordance with 4.6.5.7. The cured coating shall have a minimum pencil hardness of “F” when tested in accordance with 4.6.5.22. 3.2.8 Resistance to Water The cured coatings shall show no blistering, softening in excess of 1 hardness unit, leaching, corrosion extending more than 1/8 inch (3.2 mm) be
31、yond the scribe mark or in from the edge of the panel, loss of adhesion, or other visible deleterious effect when tested as specified in 4.6.5.8. 3.2.9 Resistance to Salt Water and Fuel The cured coatings shall show no blistering, softening in excess of 1 hardness unit, leaching, shrinkage, corrosio
32、n extending more than 1/8 inch (3.12 mm) beyond the scribe mark or in from the edge of the panel, loss of adhesion, or other visible deleterious effect when tested as specified in 4.6.5.9. 3.2.10 Resistance to Engine Oil The cured coatings shall show no blistering, softening in excess of 1 hardness
33、unit, leaching, shrinkage, loss of adhesion, or other visible deleterious effect when tested as specified in 4.6.5.10. 3.2.11 Resistance to Hydraulic Fluid The cured coatings shall show no blistering, softening in excess of 1 hardness unit, leaching, shrinkage, loss of adhesion, or other visible del
34、eterious effect when tested as specified in 4.6.5.11. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AMS-C-27725C - 5 - 3.2.12 Fuel Contamination The nonvolatile extractable materials contribute
35、d by the cured coatings in contact with the jet reference fluid shall not be more than 20 mg per 100 ml when tested as specified in 4.6.5.12. Not more than a slight discoloration or tarnish shall be present on a freshly polished copper strip. 3.2.13 Low-Temperature Flexibility The cured coatings sha
36、ll withstand the low-temperature test specified in 4.6.5.13 without cracking, checking, crazing, or loss of adhesion. 3.2.14 Peel Strength, Sealing Compound to Coating Material Sealing compound conforming to AMS 3276, Class B-2, applied to the cured coating material shall have a peel strength of not
37、 less than 20 pounds force per inch (3503 N/m) when tested as specified in 4.6.5.14. There shall be no adhesive failure between the coating and the sealing compound except for bubbles and knife cuts. 3.2.15 Adhesion, Coating Material to Sealing Compound The coating material applied to sealing compou
38、nd conforming to AMS 3276, Class B-2, shall not cause cracks in the sealing compound when tested as specified in 4.6.5.15. Cracks in the cured coating shall be permissible, but the cured coating shall not flake from the sealant. 3.2.16 Repairability The cured coating shall show no blistering or loss
39、 of adhesion when tested as specified in 4.6.5.16. 3.2.17 Accelerated Storage Stability After storing as specified in 4.6.5.17, coating material shall be capable of meeting the initial viscosity requirements and the requirements for dry time and application life specified in Table 1. 3.2.18 Resistan
40、ce to Iron Chloride The cured coatings shall show no blistering or softening, and the panels shall show no corrosion when tested as specified in 4.6.5.18.1. After immersion, the cured coatings shall have a resistance of at least 5.0 megohms per mil of thickness when tested as specified in 4.6.5.18.2
41、. 3.2.19 Resistance to Simulated Microbial By-Products The cured coatings shall show no blistering, softening, or shrinkage when tested as specified in 4.6.5.19. There shall be not more than 5 percent loss of coating when subjected to the tape test. Removal of coating immediately adjacent to the scr
42、ibe and obviously caused by coating cracking during scribing shall not be cause for rejection. 3.3 Quality The coatings, as received by purchaser, shall be uniform in quality and condition, as free from foreign materials as commercially practicable and free from imperfections detrimental to the usag
43、e of the compound. There shall be no separation of ingredients that cannot be readily dispersed by hand mixing. 4. QUALITY ASSURANCE PROVISIONS 4.1 Quality System of Manufacturer Before submitting a product for qualification to this specification for the purpose of being listed on the PRI QPL, the m
44、anufacturer must have a quality system in place which holds a third party accreditation to AS9100. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE AMS-C-27725C - 6 - 4.2 Responsibility for Inspec
45、tion The manufacturer of the product shall supply all samples needed for required tests and shall be responsible for the performance of all required tests. Purchaser reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that the product conforms to specified
46、 requirements. 4.3 Classification of Tests 4.3.1 Acceptance Tests Surface appearance (3.2.1), density (3.2.2), volatile content (3.2.3), viscosity (3.2.4), application life (3.2.5), drying time (3.2.6), and force cure time (3.2.7) are acceptance tests and shall be performed on each batch. 4.3.2 Qual
47、ification Tests All technical requirements are qualification tests and shall be performed prior to the initial shipment of coating to a purchaser, when a change in ingredients and/or processing requires re-approval as in 4.5.4, and when purchaser deems confirmatory testing to be required. All qualif
48、ication testing is to be carried out by a laboratory which is independent of the manufacturer and is accredited per ISO 17025 and AS5505. 4.4 Sampling and Testing Shall be as follows: 4.4.1 For Acceptance Tests Sufficient coating compound shall be taken at random from each batch to perform all the r
49、equired tests. A batch shall be the quantity of material run through a mill or mixer at one time. The number of determinations for each required test shall be as specified in the applicable test procedure or, if not specified herein, not less than three, except that multiple testing is not required for viscosity, application life, drying time, and forced cure time. 4.4.1.1 A statistical sampling plan, acceptabl
