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/ARP6903 AEROSPACE RECOMMENDED PRACTICE ARP6903 Issued 2017-03 Guide for Achieving Plating/Finis
5、h Compatibility with Connectors and Accessories used in Electrical Wiring Interconnect Systems (EWIS) RATIONALE This document provides users a means to identify and select compatible galvanic couples to achieve the best connector and accessory plating/finish performance. Individual component specifi
6、cations do not address finish selection for different plating configurations affecting the entire EWIS performance as a system (Backshell to Connector Plug to Connector Receptacle to Backshell). 1. SCOPE The intent of this ARP is to provide guidance to assist users in choosing compatible component f
7、inishes/platings to achieve the best corrosion resistance performance for compatible components/couples. This SAE Recommended Practice is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances. A galvanic compatibililty table is prov
8、ided to assist with the compatible plating/finish selection. Specific plating performance parameters for each individual plating and each connector/accessory specification have also been provided to assist the product user with compatible plating/finish selection. 1.1 Purpose This SAE Recommended Pr
9、actice (ARP) serves as a guide to assist users in choosing compatible connector/accessory finish/plating combinations to achieve the best corrosion resistance performance. Failure to select and employ suitable finish/plating combinations, may negatively impact reliabilty (service life) and performan
10、ce of individual EWIS components, and the entire system in which it is installed. 2. REFERENCES The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in e
11、ffect on the date of the purchase order. In the event of conflict between the text of this document and 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. 2.
12、1 Applicable Documents The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between
13、 the text of this document and 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. SAE INTERNATIONAL ARP6903 Page 2 of 9 2.1.1 SAE Publications Available from
14、 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. AS29600 Connectors, Electrical, Circular, Miniature, Composite, High Density, Quick Coupling, Environment Resistant, Removable Crimp Contact
15、s Associated Hardware, General Specification For AS81511 Connectors, Electrical, Circular, High Density, Quick Disconnect, Environment Resisting and Accessories, General Specification For AS81582 Connectors, Electrical, Bayonet Coupling, Environment Resisting, Umbilical, General Specification For AS
16、81659 Connectors, Electrical, Rectangular Crimp Contacts, General Specification For AS81703 Connectors, Electric, Circular, Miniature, Rack and Panel Or Push-Pull Coupling, Environment Resisting AS85028 Connector, Electrical, Rectangular, Individual Contact Sealing, Polarized Center Jackscrew, Plug,
17、 Crimp Removable Pin Contacts, Class E AS85049 Connector Accessories, Electrical General Specification For AS95234 Connectors, Electrical, Reverse Bayonet, General Specification For 2.1.2 Military Specification and Standards Copies of these documents are available online at http:/quicksearch.dla.mil
18、. MIL-STD-889 Dissimilar Metals MIL-DTL-24308 Connectors, Electric, Rectangular, Nonenvironmental, Miniature, Polarized Shell, Rack and Panel, General Specification for MIL-DTL-26482 Connectors, Electrical, (Circular, Miniature, Quick Disconnect, Environment Resisting), Receptacles and Plugs, Genera
19、l Specification for MIL-DTL-26500 Connectors, General Purpose, Electrical, Miniature, Circular, Environment Resisting, General Specification for MIL-PRF-28876 Connectors, Fiber Optic, Circular, Plug and Receptacle Style, Multiple Removable Termini, General Specification for MIL-DTL-38999 Connectors,
20、 Electrical, Circular, Miniature, High Density, Quick Disconnect (Bayonet, Threaded, or Breech Coupling), Environment Resistant with Crimp Removable Contacts or Hermetically Sealed with Fixed, Solderable Contacts, General Specification for MIL-PRF-39012 Connectors, Coaxial, Radio Frequency, General
21、Specification for MIL-DTL-83723 Connectors, Electrical, (Circular, Environment Resisting), Receptacles and Plugs, General Specification for SAE INTERNATIONAL ARP6903 Page 3 of 9 3. COMPATIBILITY DETAILS Proper selection of finish/plating combinations in the design of EWIS will result in fewer interm
22、etallic interface (galvanic) problems. For example, silver has an anodic index of 15 and tin 65, the EMF generated as a couple is 0.50 V, which is not allowable as specified in Table 1. Compatible couples are deemed as having a maximum potential difference of 0.25 V between groups. In this case, oth
23、er finish/plating combinations will be required. It should be noted that, in intermetallic couples, the member with the higher anodic index is anodic to the member with the lower anodic index and will be susceptible to corrosion in the presence of an electrolytic medium. Table 1 provides metal, fini
24、sh/plating compatibility information. Table 2 provides a reference of the most common aerospace connector family finish/plating and performance requirements and defines its applicable compatibility group. MIL-STD-889 provides additional metal compatibility and chart with applicable reactance values
25、for typical metals when subjected to electrolysis in water with 2% salt. 3.1 Connector to Structure (e.g., Box Mount, Jam Nut, or Wall Mount) Use Table 1 to identify the Group Number for the structure to which the connector will be mounted. Use Table 2 to identify the compatible connector plating/fi
26、nish based on its applicable Group Number. The best compatible couples are ones which use the same Group Number. If different, use the most anodic material (for the connector) and look for the Group Number with the most compatible couple with the structures Group Number. Compatible couples are deeme
27、d as having a maximum potential difference of 0.25 V between groups. Material selection for intermetallic contact parts, should establish the smaller part (connector) be the anodic, replaceable member of the couple, whenever practical. 3.2 Connector to Connector Use Table 2 to identify the connector
28、 plating/finish and its applicable Group Numbers for both the plug and receptacle sides. Use Table 1 to select compatible mating connector couples based on the Group Numbers. The best compatible couples are ones which use the same Group Number. If different, start with the most anodic material based
29、 on the compatible couples by Group Number. Compatible couples are deemed as having a maximum potential difference of 0.25 V between groups. 3.3 Connector to Accessory Use Table 2 to identify the applicable plating/finish and its associated Group Number for the connector. Identify compatible couple
30、choices for the accessory based on the Connector Group Number. The best compatible couples are ones which use the same Group Number. If different, start with the most anodic material based on the compatible couples by Group Number. Compatible couples are deemed as having a maximum potential differen
31、ce of 0.25 V between groups. Use Table 1 to identify the accessory plating/finish by Group Number. Use accessory detail sheet (i.e., AS85049) to identify suitable finish/plating configurations. For optimum performance, the plating material selected for the connector should match that plating materia
32、l selected for the accessory. Note that plating/finish code letters may differ between connector and accessory specifications (e.g., MIL-DTL-38999 finish “T” is the same as “X” in AS85049). SAE INTERNATIONAL ARP6903 Page 4 of 9 Table 1 - Compatible couples Group Number Metallurgical Category EMF (V)
33、 Anodic Index (0, 01 V) Compatible Couples (Group Number) 1 Gold, solid and plated; gold-platinum alloys/wrought platinum (most cathodic) +0.15 0 1, 2, 3 2 Rhodium plated on silver-plated copper +0.05 10 2, 3, 4, 5 3 Silver, solid or plated; high silver alloys 0 15 3, 4, 5, 6 4 Nickel, solid or plat
34、ed; monel metal, high nickel-copper alloys -0.15 30 4, 5, 6, 7, 8 5 Copper, solid or plated; low brasses or bronzes; silver solder; German silver; high copper-nickel alloys; nickel chromium alloys; austenitic corrosion-resistant steels -0.20 35 5, 6, 7, 8, 9 6 Commercial yellow brasses and bronzes.
35、-0.25 40 6, 7, 8, 9, 10 7 High brasses and bronzes; naval brass; Muntz metal -0.30 45 7, 8, 9, 10, 11 8 Eighteen percent chromium type corrosion-resistant steels -0.35 50 8, 9, 10, 11, 12 9 Chromium, plated; tin, plated; twelve percent chromium type corrosion-resistant steels -0.45 60 9, 10, 11, 12,
36、 13 10 Tin-plate; terneplate; tin-lead solder -0.50 65 10, 11, 12, 13, 14 11 Lead, solid or plated; high lead alloys -0.55 70 11, 12, 13, 14, 15 12 Aluminum, wrought alloys of the duralumin type -0.60 75 12, 13, 14, 15 13 Iron, wrought, gray, or malleable; plain carbon and low alloy steels, Armco ir
37、on -0.70 85 13, 14, 15 14 Aluminum, wrought alloys other than duralumin type; aluminum, case alloys of the silicon type -0.75 90 14, 15 15 Aluminum, cast alloys other than silicon type; cadmium, plated and chromated -0.80 95 15, 16 16 Hot-dip-zinc plate; galvanized steel -1.05 120 16, 17 17 Zinc, wr
38、ought; zinc-base die-casting alloys; zinc, plated -1.10 125 16, 17 18 Magnesium and magnesium-base alloys, cast or wrought (most anodic) -1.60 175 None NOTES: Compatible couples potential difference of 0.25 V maximum between groups. Group number 1 is the most cathodic, noble, or resistant to corrosi
39、on, while group number 18 is the most anodic, or easiest to corrode. Trademark Notice: “ARMCO” is the registered trademark of: Armco Tactical (87121988), A.R.M.C.O. Atlantic Records Management Company (75574367/2309005), and Armco (71527716/0534852). SAE INTERNATIONAL ARP6903 Page 5 of 9 Table 2 - C
40、onnector and accessory specification finishes/table 1 group number Connector/ Accessory Specification/ Document Finishes perform mate/de-mate of connector per applicable specification; final corrosion resistance for total duration-n hours. SAE INTERNATIONAL ARP6903 Page 9 of 9 4. NOTES 4.1 Revision
41、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 the previous issue of a document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revision. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. PREPARED BY SAE SUBCOMMITTEE AE-8C1, CONNECTORS OF COMMITTEE AE-8, AEROSPACE ELECTRICAL/ELECTRONIC DISTRIBUTION SYSTEMS STEERING GROUP
