SAE AMS 2420E-2017 Plating of Aluminum for Solderability Zinc Immersion Pre-Treatment Process.pdf

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 revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2017 SAE International All rights reserved. No part of this p

3、ublication may 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: +1 724-776-497

4、0 (outside USA) 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:/standards.sae.org/AMS2420E AEROSPACE MATERIAL SPECIFICATION AMS2420 REV. E Issued 1957-07 Reaffirmed 2012-08 Revi

5、sed 2017-11 Superseding AMS2420D Plating of Aluminum for Solderability Zinc Immersion Pre-Treatment Process RATIONALE AMS2420E results from a Five-Year Review and update, with changes made to Ordering Information and paragraphs 4.2.1, 4.2.2, 4.2.3, 4.3.1.1, 4.3.2, and 4.3.4.1. ORDERING INFORMATION:

6、The following information shall be provided to the plating processor by the purchaser. 1) Purchase order shall specify not less than the following: AMS2420E Quantity of pieces to be plated Permissible electrical contact locations, if not specified (see 3.2.2.1) Class of plating desired (see 1.3) Pla

7、ting thickness desired if other than that specified in 3.3.1 Basis metal to be plated Reflow, when necessary (see 3.2.4) 2) Parts manufacturing operations such as heat treating, forming, joining and media finishing can affect the condition of the substrate for plating, or if performed after plating,

8、 could adversely affect the plated part. The sequencing of these types of operations should be specified by the cognizant engineering organization and is not controlled by this specification. SAE INTERNATIONAL AMS2420E Page 2 of 7 1. SCOPE 1.1 Purpose This specification covers the requirements for p

9、reparation of aluminum and aluminum alloys for soldering by zinc immersion pre-treatment followed by copper plating and tin or tin-zinc alloy plating. 1.2 Application This process has been used typically to facilitate soldering of aluminum and aluminum alloy mechanical and electronic instrument encl

10、osures, but usage is not limited to such applications. 1.3 Classification The final plating shall be one of the following. When a Class is not specified, Class 1 shall apply. Class 1 - Tin Plating Class 2 - Tin-Zinc Plating 1.4 Safety-Hazardous Materials While the materials, methods, applications, a

11、nd 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 user to ensure familiarity with the safe and proper use of any hazardous mate

12、rials and to take necessary precautionary measures to ensure the health and safety of all personnel involved. 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 w

13、ork to a subsequent revision of a document unless a specific document issue is specified. When the referenced document has been canceled 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 C

14、ommonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. AMS2408 Plating, Tin AMS2418 Plating, Copper AMS2434 Plating, Tin-Zinc Alloy AMS4751 Tin - Lead Eutectic, 63Sn - 37Pb ARP1917 Clarification of Terms Used in Aerospac

15、e Metals Specifications ARP4992 Periodic Test for Processing Solutions AS2390 Chemical Process Test Specimen Material SAE INTERNATIONAL AMS2420E Page 3 of 7 2.2 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9

16、585, www.astm.org. ASTM B253 Preparation of Aluminum Alloys for Electroplating ASTM B487 Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross Section ASTM B567 Measurement of Coating Thickness by the Beta Backscatter Method ASTM B568 Measurement of Coating Thickness

17、 by X-Ray Spectrometry ASTM B571 Qualitative Adhesion Testing of Metallic Coatings 3. TECHNICAL REQUIREMENTS 3.1 Preparation 3.1.1 Cleaning and Deoxidizing Parts shall have clean, water break-free surfaces and shall be deoxidized to prepare for zinc immersion coating as a pretreatment for plating. 3

18、.2 Procedure 3.2.1 Zinc Immersion Coating Parts shall be processed in accordance with ASTM B253 or other method acceptable to purchaser. 3.2.2 Plating Parts shall be pre-plated with a brass or copper strike from an alkaline solution, followed by electrodeposition of copper in accordance with AMS2418

19、. When Class 1 is specified, parts shall receive a final deposit of tin in accordance with AMS2408. When Class 2 is specified, parts shall receive a final deposit of a tin-zinc alloy in accordance with AMS2434 with a maximum of 25% zinc. 3.2.2.1 Except for barrel plating, electrical contact points s

20、hall 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. 3.2.3 Spotting-in is not permitted. 3.2.4 When reflow is specified for tin plate the

21、 deposit shall be reflowed to a bright, shiny appearance by immersion in hot oil at 490 to 525 F (254 to 274 C). 3.3 Properties The deposit shall conform to the following requirements: 3.3.1 Thickness Shall be as follows, determined in accordance with ASTM B487, ASTM B567, ASTM B568, or other method

22、 acceptable to purchaser. 3.3.1.1 Copper Plate Shall be 0.0003 to 0.0007 inch (8 to 18 m). SAE INTERNATIONAL AMS2420E Page 4 of 7 3.3.1.2 Tin or Tin-Zinc Alloy Plate Shall be 0.0003 to 0.0005 inch (8 to 13 m). 3.3.1.3 The plate shall be substantially uniform in thickness on significant surfaces, exc

23、ept that build-up at exterior corners or edges will be permitted provided finished drawing dimensions are met. 3.3.1.4 No requirements are established for minimum plate thickness on surfaces of holes, recesses, internal threads, contact areas of parts plated all over, and other areas where a control

24、led deposit cannot be obtained under normal plating conditions, but such surfaces 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 (19.0 mm) in diameter. 3.3.2 Heat Resistance Parts shall show no visual e

25、vidence of blistering after reflow or after being held at 350 F 10 F(177 C 6 C) for 30 minutes 3 minutes. 3.3.3 Adhesion Plate shall be firmly and continuously bonded to the underlying metal, determined, on representative parts or a test specimen as in 4.3.3, in accordance with a method described in

26、 ASTM B571. There shall be no indication of separation from the base metal or internal delamination. In case of dispute, the bend test shall apply. 3.3.4 Solderability The plating shall demonstrate good solderability using AMS4751 tin/lead solder and a mildly activated rosin (RMA) flux. The solder s

27、hall flow uniformly and show no evidence of dewetting except for surfaces exempt from coating thickness requirements as in 3.3.1.4. 3.4 Quality Plating shall be smooth, continuous, free from delamination within the plating, uniform in appearance and free from imperfections detrimental to usage of th

28、e plating. Plating shall be visually free from frosty areas, pin holes, porosity, blisters, nodules, and pits. Slight staining or discoloration is permissible. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection The processor shall supply all specimens for processors tests and shall be

29、 responsible for the performance of all required tests. Parts, if required for tests, shall be supplied by purchaser. Purchaser reserves the right to sample and to perform any confirmatory tests deemed necessary to ensure that processing conforms to specified requirements. 4.2 Classification of Test

30、s 4.2.1 Acceptance Tests Thickness (3.3.1), heat resistance (3.3.2), solderability (3.3.4), and quality (3.4) are acceptance tests and shall be performed on each lot. 4.2.2 Periodic Tests Adhesion (3.3.3) is a periodic test that shall be performed no less than daily for each generic class of alloy a

31、s defined by AS2390 processed during that day. Tests of preparatory and plating solutions (see 8.4) to ensure that the deposited metal will conform to specified requirements are periodic tests and shall be performed at a frequency established by the processor unless frequency of testing is specified

32、 by the cognizant engineering organization. SAE INTERNATIONAL AMS2420E Page 5 of 7 4.2.3 Preproduction Tests All property verification tests are preproduction tests and shall be performed prior to or on the initial shipment of processed parts to a purchaser, when a change in materials and/or process

33、ing requires approval by the cognizant engineering organization (see 4.4) 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 processed in the same solution(s) in not longer than

34、 eight consecutive hours, and presented for processors inspection at one time. 4.3.1 Acceptance Tests 4.3.1.1 Quality, Heat Resistance, Solderability, and Thickness As shown in Table 1. Table 1 - Minimum sampling for acceptance testing Number of Parts in Lots Quality Thickness, Heat Resistance, and

35、Solderability Up to 7 All 3 8 to 15 7 4 16 to 40 10 4 41 to 110 15 5 111 to 300 25 6 301 to 500 35 7 Over 500 50 8 4.3.2 Periodic Tests For adhesion tests, four test specimens of each generic class of alloy, as defined by AS2390, that have been be processed through the same cleaning and plating oper

36、ations as the parts that they represent. These adhesion test specimens shall be processed prior to the first production lot of parts or with the first production lot of parts. 4.3.3 Preproduction Tests Shall be acceptable to purchaser. 4.3.4 Test Specimens Where practical, tests shall be performed o

37、n actual parts. Nondestructive testing shall be performed wherever practical and where authorized herein. When destructive tests are required and plated parts are of such configuration or size as to be not readily adaptable to the specified tests, separate test specimens may be used provided they ar

38、e made of the same generic class of alloy, cleaned, plated, and post-treated with the parts represented. Specimens shall be either panels approximately 0.032 x 1 x 4 inches (0.81 x 25 x 102 mm) or bars approximately 0.5 inch (13 mm) in diameter and 4 inches (102 mm) long. 4.3.4.1 Test specimens for

39、adhesion testing shall be made of the same generic class of alloy processed as defined by AS2390. The test specimens shall be 0.025 inch (0.6 mm) minimum thickness and not less than 1 x 4 inches (25 x 102 mm). 4.4 Approval 4.4.1 The process and control procedure, a preproduction sample, or both, whi

40、chever is specified by purchaser, shall be approved by the cognizant engineering organization before production parts are supplied. SAE INTERNATIONAL AMS2420E Page 6 of 7 4.4.2 The processor shall make no significant change to materials, processes, or control factors from those on which the approval

41、 was based, unless the change is approved by the cognizant engineering organization. A significant change is one which, in the judgment of the cognizant engineering organization, could affect the properties or performance of the parts. 4.4.3 Control factors shall include, but not be limited to, the

42、following: Surface preparation and cleaning procedures Surface activation procedures Plating bath compositions and control limits Plating bath temperature limits and controls Current/voltage/time limits and controls Method for testing plating thickness Method for checking adhesion 4.5 Reports The pr

43、ocessor shall furnish with each shipment a report stating that the parts have been processed and tested in accordance with specified requirements and that they conform to the technical requirements. This report shall include the purchase order number, lot number, AMS2420E, part number, quantity, and

44、 class of plating. 4.6 Resampling and Retesting 4.6.1 If any lot acceptance test fails to meet specified requirements, parts in that lot may be stripped by a method acceptable to purchaser that does not roughen, pit or embrittle the basis metal or adversely affect part dimensions, pretreated, plated

45、, post treated as defined herein and tested. Alternatively, all parts in the lot may be inspected for the nonconforming attribute, and the nonconforming parts may be stripped by a method acceptable to purchaser that does not pit, roughen embrittle the basis metal, or adversely affect part dimensions

46、, pretreated, plated, post treated as defined herein, and tested. After any stripping and replating, parts shall meet the requirements of the drawing. 4.6.2 If the result of any periodic test fails to meet specified test requirements, the process is nonconforming. No additional parts shall be plated

47、 until the process is corrected and new specimens are plated and tested. Results of all tests shall be recorded and, when requested, reported. Purchasers shall be notified of all parts plated since the last acceptable test. 5. PREPARATION FOR DELIVERY 5.1 Packaging 5.1.1 Plated parts shall be handle

48、d and packaged to ensure that the required physical characteristics and properties of the plating are preserved. 5.1.2 Packages of processed parts shall be prepared for shipment in accordance with commercial practice and in compliance with applicable rules and regulations pertaining to handling, pac

49、kaging, and transportation of processed parts to ensure carrier acceptance and safe delivery. 6. ACKNOWLEDGMENT A vendor shall mention this specification number and its revision letter in all quotations and when acknowledging purchase orders. 7. REJECTIONS Parts on which the plating does not conform to this specification, or to modifications authorized by purchaser, will be subject to rejection. SAE INTER