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 ther
2、efrom, 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
3、publication 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: +1 724-776-49
4、70 (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/AMS2451/12A AEROSPACE MATERIAL SPECIFICATION AMS2451 /12 REV. A Issued 2002-12 Revised 2017-11
5、 Superseding AMS2451/12A Plating, Brush, Tin RATIONALE AMS2451/12A is the result of a Five-Year Review and update of this specification with changes to paragraph 3.2.2 hydrogen embrittlement. 1. SCOPE 1.1 Purpose This specification covers the engineering requirements and process for brush plating of
6、 tin by electrodeposition. It shall be used, in conjunction with AMS2451, for general purpose tin deposits. 1.2 Application This process has been used typically to prevent galling or seizing of metal surfaces, to provide a surface for soft soldering, or to improve corrosion resistance, but usage is
7、not limited to such applications. 1.3 Safety - Hazardous Materials Shall be in accordance with AMS2451. 2. APPLICABLE DOCUMENTS In addition to those listed in AMS2451, the issue of the following documents in effect on the date of the purchase order forms a part of this specification to the extent sp
8、ecified herein. The supplier may work to a subsequent revision of a document unless a 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 Avai
9、lable from SAE International, 400 Commonwealth 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 AMS2451 Plating, Brush, General Requirements SAE INTERNATIONAL AMS2451/12A Page 2 of 3 2.2 ASTM Publications
10、Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM B545 Electrodeposited Coatings of Tin 3. TECHNICAL REQUIREMENTS Shall be in accordance with AMS2451 and as follows. 3.1 Procedure 3.1.1 Except as required
11、in 3.1.1.1 or 3.1.2, tin shall be electroplated directly on the basis metal from a suitable brush plating solution in accordance with processing instructions from the solution manufacturer. 3.1.1.1 For aluminum and aluminum alloys, a zinc immersion preplate may be used. 3.1.2 Prior to electrodeposit
12、ion of tin for solderability on aluminum or copper-zinc alloy parts, a copper plate shall be deposited to a thickness of 0.0002 to 0.0003 inch (5.1 to 7.6 m). 3.2 Properties 3.2.1 Thickness Where “tin flash” is specified, plate thickness shall be approximately 0.0001 inch (2.5 m). 3.2.2 Hydrogen Emb
13、rittlement Shall be in accordance with AMS2451. 3.2.3 Solderability When specified, solderability of the plating shall be in accordance with ASTM B545. The method of test shall be as specified by purchaser. 3.2.4 Continuity of Plating When specified, plating on ferrous parts, having a plating thickn
14、ess of 0.0004 inch (10 m) or more, shall be subjected to the porosity test of ASTM B545 and the result evaluated according to the procedure described. When specified, plating on copper and copper alloys shall be subjected to the porosity test for copper basis metal given in ASTM B545: the specimens
15、shall be considered to have failed if pores in the coating blacken by the polysulfide test. 4. QUALITY ASSURANCE PROVISIONS Shall be in accordance with AMS2451. 5. PREPARATION FOR DELIVERY Shall be in accordance with AMS2451. 6. ACKNOWLEDGEMENT Shall be in accordance with AMS2451. 7. REJECTIONS Shal
16、l be in accordance with AMS2451. SAE INTERNATIONAL AMS2451/12A Page 3 of 3 8. NOTES See AMS2451 and as follows. 8.1 Revision Indicator A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to
17、the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. 8.2 When using tin plati
18、ng for electronics and precision moving parts applications, the potential for formation of tin whiskers should be considered. Under certain circumstances, metal whiskers grow from surfaces of tin electrodeposits. The tin whiskers are electrically conductive and some have measured 40 to 80 millionths
19、 of an inch in diameter with lengths up to 0.375 inch. Whiskers can reduce the electrical resistance between surfaces or cause short circuits. In the case of precision moving parts, displaced whiskers can cause mechanical interference. 8.3 Plating thickness greater than 0.0003 inch (8 m) may result in tearing and dewetting during reflow. 8.4 The plating meeting the requirements of this specification will exhibit equivalent properties to plating produced in accordance with AMS2408. PREPARED BY AMS COMMITTEE “B”
