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 there
2、from, 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 2012 SAE International All rights reserved. No part of this publication m
3、ay 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: +1 724-776-4970 (outside U
4、SA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AMS2425F AEROSPACE MATERIAL SPECIFICATION AMS2425 REV. F Issued 1966-03 Reaffirmed 2006-09 Re
5、vised 2012-12 Superseding AMS2425E Plating, Gold for Thermal Control RATIONALE AMS2425F results from a Five Year Review and update of this specification and adds ordering information consistent with other AMS plating specifications. NOTICE ORDERING INFORMATION: The following information shall be pro
6、vided to the plating processor by the purchaser. Purchase order shall specify not less than the following: AMS2425F. Plating thickness desired (3.4.2) and minimum thickness on internal surfaces, if required (3.4.2.4) Basis metal to be plated Tensile strength or hardness of the basis metal Pre-plate
7、stress relief to be performed by plating processor (time and temperature) if different from 3.1.1 Special features, geometry or processing present on parts that requires special attention by the plating processor Hydrogen embrittlement relief to be performed by plating processor (parameters or refer
8、ence document) if different from 3.3 Periodic testing frequency and sample quantity, if different from 4.2.2 and 4.3.3. Quantity of pieces to be plated Parts manufacturing operations such as heat treating, forming, joining and media finishing can affect the condition of the substrate for plating, or
9、 if performed after plating, could adversely affect the plated part. The sequencing of these types of operations should be specified by the cognizant engineering organization or purchaser and is not controlled by this specification. SAE AMS2425F Page 2 of 8 1. SCOPE 1.1 Purpose This specification co
10、vers the requirements for gold deposited on metal surfaces and the properties of the deposit. 1.2 Application This process has been used typically for passive thermal control applications where high reflectance and low absorptance of solar radiation are required, but usage is not limited to such app
11、lications. 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 specific document issue is specified. When the
12、referenced document has been cancelled and no superseding document has been specified, the last published issue of that document shall apply. 2.1 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.o
13、rg. ASTM B 117 Operating Salt Spray (Fog) Testing Apparatus ASTM B 253 Preparation of Aluminum Alloys for Electrodeposition ASTM B 487 Measurement of Metal and Oxide Coating Thicknesses by Microscopical Examination of a Cross Section ASTM B 499 Measurement of Coating Thicknesses by the Magnetic Meth
14、od: Nonmagnetic Coatings on Magnetic Basis Metals ASTM B 504 Measurement of Thickness of Metallic Coatings by the Coulometric Method ASTM B 567 Measurement of Coating Thickness by the Beta Backscatter Method ASTM B 583 Porosity in Gold Coatings on Metal Substrates 2.2 ANSI Publications Available fro
15、m American National Standards Institute, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org. ANSI B46.1 Surface Texture 3. TECHNICAL REQUIREMENTS 3.1 Preparation 3.1.1 Ferrous parts having a hardness higher than 40 HRC and which have been ground after heat treatment shall
16、be cleaned to remove surface contamination and suitably stress relieved before preparation for plating. Temperatures to which parts are heated shall be such that maximum stress relief is obtained without reducing hardness of parts below drawing limits, but unless otherwise specified not less than 27
17、5 F (135 C) for not less than 5 hours for parts having hardness of 55 HRC or higher or not less than 375 F (191 C) for not less than 4 hours for other parts. SAE AMS2425F Page 3 of 8 3.1.2 Texture of surfaces to be plated, prior to cleaning, shall be not rougher than 32 microinches (0.8 m), determin
18、ed in accordance with ANSI B46.1. Light abrasive blasting and polishing are permitted to improve surface finish to produce a high luster. 3.1.3 Parts shall have clean surfaces free of waterbreak prior to immersion in the plating solution. 3.1.4 Except for barrel plating electrical contact points sha
19、ll be as follows: For parts which are to be plated all over, locations shall be acceptable to purchaser; for parts which are not to be plated all over, locations shall be in areas on which plating is not required or is optional. 3.2 Procedure Parts shall be plated in the following sequence using sui
20、table plating solutions. A zincate immersion coating treatment in accordance with ASTM B 253 shall be applied to aluminum or aluminum alloys prior to plating. Copper Flash or Strike Nickel Plate Gold Plate 3.2.1 Copper Flash or Copper Strike A copper flash or copper strike shall be electrodeposited
21、from a suitable copper plating bath except as exempted in 3.2.1.1, 3.2.1.2, and 3.2.1.3. 3.2.1.1 A nickel flash or nickel strike shall replace the copper strike when the basis metal is corrosion- resistant steel. The nickel flash or nickel strike shall be electrodeposited from a suitable nickel plat
22、ing solution. 3.2.1.2 The copper strike may be omitted when the substrate is copper or a copper alloy containing less than 15% zinc. 3.2.1.3 Parts that have been zincated do not require a copper flash or strike. 3.2.2 Nickel Plate The nickel plate shall be deposited directly onto the copper strike o
23、r flash or, when specified as in 3.2.1.1, onto the nickel strike or flash. Either electroplating or electroless nickel processing is permitted. 3.2.3 Gold Plate Shall be electrodeposited from a suitable gold plating solution directly onto the nickel surface. 3.2.4 Rinsing The plated part shall be re
24、moved from the plating solution and shall be thoroughly rinsed by immersion for not less than 15 minutes in water at not lower than 180 F (82 C) and dried. 3.2.4.1 Plated springs may be removed from the plating racks after rinsing provided they are not flexed prior to embrittlement relief. 3.3 Hydro
25、gen Embrittlement Relief After plating, rinsing, and drying and within 4 hours after removal from plating bath ferrous parts shall be treated as follows. SAE AMS2425F Page 4 of 8 3.3.1 Parts having hardness of 33 HRC or higher shall be heated to 375 F 25 (191 C 14) and held at heat for not less than
26、 3 hours. 3.3.2 Parts which will decrease in hardness or be otherwise deleteriously affected by heating to 375 F 25 (191 C 14) shall be heated to 275 F 25 (135 C 14) and held at heat for not less than 5 hours. 3.3.3 Polishing of plated metals is permitted to improve surface finish and luster. 3.4 Pr
27、operties Plated metals shall conform to the following requirements: 3.4.1 Composition The gold, as plated, shall be not less than 98.0% pure, determined by a method acceptable to purchaser. 3.4.2 Thickness Plating thicknesses shall be as follows, determined in accordance with ASTM B 487, ASTM B 499,
28、 ASTM B 504, ASTM B 567, or other method acceptable to purchaser. 3.4.2.1 Copper Flash or Copper Strike Shall be not less than 0.0001 inch (2.5 m). 3.4.2.2 Nickel Plate Shall be 0.0004 to 0.0009 inch (10.0 to 23 m). 3.4.2.3 Gold Plate Shall be not less than 0.00008 inch (2.0 m) on all surfaces on wh
29、ich gold is functionally necessary. 3.4.2.4 No requirements are established for minimum plate thickness on surfaces of holes, recesses, internal threads, contact areas of part plated all over, and other areas where a controlled deposit cannot be obtained under normal plating conditions but such area
30、s shall not be masked to prevent plating. The resultant thickness shall be considered only when such surfaces can be touched by a sphere 0.75 inch (19 mm) in diameter. 3.4.3 Adhesion The gold deposit shall meet one of the following tests; the test in 3.4.3.1 shall be used where practicable. 3.4.3.1
31、The part, or representative test panels, shall be bent through an angle of 100 degrees around a 0.500 inch 0.005 (12.7-mm 0.12) diameter mandrel. It shall not be possible to detach any appreciable areas of deposited gold from the basis metal with a sharp instrument although fracture of the nickel pl
32、ate or the basis metal is acceptable. 3.4.3.2 If the part is not readily adaptable to the test in 3.4.3.1, adhesion may be evaluated by heating the part to 350 F 10 (177 C 6) and holding at that temperature for not less than 1 hour. Following heating, no evidence of blistering of the plating shall b
33、e visible at 4X magnification. 3.4.4 Corrosion Resistance Parts or representative test panels shall show no corrosion products to the unaided eye (corrected to 20/20 vision) at normal reading distance or any corroded areas greater than 1/32 inch (0.8 mm) in diameter after being subjected for 48 hour
34、s 1 to continuous salt spray corrosion test conducted in accordance with ASTM B 117. SAE AMS2425F Page 5 of 8 3.4.4.1 The porosity test of ASTM B 583 may be used in lieu of the salt spray corrosion test, unless otherwise specified by purchaser. 3.4.5 Spectral Absorptance and Emittance The normal spe
35、ctral solar absorptance integrated over a wave length range 0.3 to 2.7 m shall be 0.26 0.04. The normal spectral emittance integrated over a wave length range of 2.0 to 27.0 m shall be 0.04 0.02. 3.4.5.1 The integrated normal spectral solar absorptance and integrated normal spectral emittance shall
36、be determined using Equation 1: (Eq. 1) where and are the integrated normal spectral solar absorptance and the integrated normal spectral emittance respectively, R is the normal spectral reflectance, is the wave length, and for , a = 0.3 m, b = 2.7 m, and S = Solar Spectrum and, for , a = 2.0 m, b =
37、 27.0 m, and S = Black body spectrum (for temperature of interest), and R is measured in an integrating-sphere reflectometer, preferably against a standard gold surface reference. 3.4.5.2 Total reflectance (specular and diffuse) shall be equal to or greater than 95% when measured at a wave length of
38、 0.7 m by an integrating-sphere reflectometer. (8.6) 3.5 Quality Deposits of gold plate shall be smooth, fine grained, continuous, adherent to basis metal, and of a color normally associated with high quality 24-carat gold, and shall be free from blisters, pits, nodules, indications of burning, and
39、other imperfections detrimental to performance of the gold plate. Slight discoloration does not deleteriously affect the thermal properties or corrosion resistance of the gold plate. There shall be no evidence of double plating and spotting-in after plating. 4. QUALITY ASSURANCE PROVISIONS 4.1 Respo
40、nsibility for Inspection The processor of plated parts shall supply all samples for processors tests and shall be responsible for the performance of all required tests, where parts are to be tested, the parts shall be supplied by the purchaser. Purchaser reserves the right to sample and to perform a
41、ny confirmatory testing deemed necessary to ensure that the processing conforms to the requirements of this specification. 4.2 Classification of Tests 4.2.1 Acceptance Tests Thickness (3.4.2), adhesion (3.4.3), reflectance (3.4.5.2), and quality (3.5) are acceptance tests and shall be performed on e
42、ach lot as applicable. 4.2.2 Periodic Tests Composition (3.4.1), corrosion resistance (3.4.4), spectral absorption and emittance (3.4.5.1), and tests of cleaning and plating solutions to ensure that deposits will conform to specified requirements (See 8.5) are periodic tests and shall be performed a
43、t a frequency selected by the processor unless frequency of testing is specified by purchaser. SAE AMS2425F Page 6 of 8 4.2.3 Preproduction Tests All technical requirements of this specification are preproduction tests and shall be performed prior to or on the initial shipment of plated parts to a p
44、urchaser, when a change in material, processing, or both requires reapproval as in 4.4.2, and when purchaser deems confirmatory testing to be required. 4.3 Sampling and Testing Shall be not less than the following; a lot shall be all parts of the same part number, plated to the same plate thickness
45、range in the same set of solutions, in each consecutive 24 hours of operation and presented for processors inspection at one time. 4.3.1 Sample Configuration Nondestructive testing shall be performed wherever practical and authorized herein. Except as noted actual parts shall be selected as samples
46、for test. 4.3.1.1 Thickness and Adhesion Test Separate test panels of the same generic class of alloy as the parts distributed throughout the lot, cleaned, plated and post treated with the parts represented shall be used when plated parts are of such configuration or size as to be not readily adapta
47、ble to the specified tests or when nondestructive testing is not practical on actual parts, or it is not economically acceptable to perform destructive testing on actual parts. 4.3.1.2 Corrosion Tests Panels for salt spray testing shall be low carbon steel approximately 0.032 x 4 x 6 inches (0.8 x 1
48、02 x 152 mm) or bars approximately 0.5 inches (13 mm) in diameter and 4 inches (102 mm) long, having surface roughness not exceeding 32 microinches (0.8 m). 4.3.1.2.1 If the porosity test of ASTM B 583 is used in lieu of the salt spray corrosion test, either actual parts, or panels of the same alloy
49、 and condtion, plated with the actual parts, shall be used. 4.3.2 Acceptance Tests Test samples shall be selected randomly from all parts in the lot. Unless purchaser supplies a sampling plan, the minimum number of samples shall be as shown in Table 1. TABLE 1 - SAMPLING FOR ACCEPTANCE TESTING Number of Parts in Lot Quality Thickness and Adhesion Reflectance 1 to 6 all 3 1 7 to 1
