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-----Barrier layer plating between bronze and tin
2001
regarding the plating subject, I am currently working on a project that involves phosphor bronze contacts (alloy 52100). They need to be Sn plated (90Sn-10Pb)for solderability. Is a Ni sulfamate barrier required under the Sn. I think not, however I am not sure. If a barrier is required, I specified the Ni sulfamate because of post forming.
Thank you,
Vince
vincent labianca- new london, Connecticut
when Plating tin on most of the copper alloys, Most spec.s requires that a barrier coat of some sort of Nickel be applied to prevent migration to the surface
Chris Snyderplater - Charlotte, North Carolina
2001
2001
What type of contact are you using? Is it permanent or used for connecting and disconnecting?
Answer to your question is Ni is required as barrier because cu in phosphor Bronze migrates into bronze.
I am in doubt, why you are using tin coating. Tin coating generally oxides hence it will increase the resistance of the part.
Please let me know how do you avoid this problem.
B.S Rathore- Udaipur, Rajasthan, India
This is a small IDC used for solid wire termination, which in theory, should provide a gas tight seal, so oxidation shouldn't pose a problem (?). We have a 5m ohm tolerance. Should I be considering Ag plate?
V. S. LaBianca- New London, CT (USA)
2001
I believe your question regarding the barrier layer has been answered, as far as using Sn for purposes of soldering you should be OK. This, however, may depend on storage conditions that the part will be subject to before it is soldered. Once it is soldered your Sn layer is converted to the soldering medium, I would assume Sn/Pb and therefore is no longer a factor. We make billions, literally, of electronic components every month with a pure Sn finish over Ni and have a very good solderability record. Also, there are aging tests that you can do to test the solderability of your part, the test conditions and equipment you need should be available in IPC literature. If you search the internet you can also find companies that will do this testing for you.
Rich Reifenheiser- Monterrey, Mexico
2001
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