TECHNET Archives

September 2010

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Werner Engelmaier <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Werner Engelmaier <[log in to unmask]>
Date:
Tue, 21 Sep 2010 10:40:20 -0400
Content-Type:
text/plain
Parts/Attachments:
text/plain (249 lines)
 Hi Kevin,
Now my 5 cents.
From my experience, I do not see solderability directly linked to the concentration of phosphorus co-plated with the nickel—I see however, brittle interfacial failures between the Ni-P surface and the Ni3Sn4-intermetallic compound which directly track with P-concentration at that interface. The presence of Ni3Sn4-IMC is clear evidence that there was no solderability issue—it is the concentration of the P at the interface which weakens the interfacial bond. 
Because of their superficial appearance, conditions with both too much P and too little P [causes hyper-galvanic corrosion along the grain boundaries of the Ni plating] have been termed 'black pad.'
Having too much P at the interface can be the result of improper Ni-plating, but also the result of too much Ni being dissolved in the Sn of the solder leaving to much P behind—this can happen from too many soldering operations.
Werner

 


 

 

-----Original Message-----
From: Glidden, Kevin <[log in to unmask]>
To: [log in to unmask]
Sent: Tue, Sep 21, 2010 8:52 am
Subject: [TN] Solderability of nickel plating


All,



Can anyone comment on the solderability of the nickel plate, particularly with 

regard to type of plating: high phosphor / low phosphor, and also storage 

conditions:



I've been gathering info, and seen conflicting information.



From one article: http://corrosion-doctors.org/MetalCoatings/Electroless.htm



A paper submitted at the Electroless Nickel conference of 1989 held in 

Cincinnati Ohio, Titled "Solderability Parameters of Elecroless Nickel Bearing 

Electronic Finishes" By Louis Kosarek of STB Systems, Inc. report that "An 

electroless nickel deposit which contains a concentration of phosphorus ranging 

from 0.1% to 3.0% is readily solderable on an "As-plated Basis" per Mil-Std 883c 

method 2003. The frequency of solderability tests which fail per Mil-Std 883c 

will increase as the phosphorus content of electroless nickel alloy increases 

from 3.0 to 7.0% phosphorus. A solderability test conducted per Mil-Std 883c 

method 2003 incorporating an as-plated surface finish containing phosphorus in 

excess of 7%, the components will consistently fail. The mode of failure is 

non-wetting of the surface."

This indicates low phosphorous plating is best for solderability.  Many other 

papers seem to agree with this.



---------------------------------------------------------------------------------------------------------------------



From another article: http://www.pfonline.com/articles/pfd0024.html



Solderability/Weldability.  An important aspect of electroless nickel to the 

electronics industry is its solderability. All electroless nickel deposits are 

solderable provided the soldering conditions are matched to the condition of the 

particular electroless nickel deposit. Lower-phosphorus electroless nickel is 

more easily solderable immediately after plating than higher-phosphorus 

electroless nickel. However, this advantage disappears after 12 - 24 hrs. At 

this point, the ease of solderability depends upon the characteristics of the 

passive layer that forms on the surface of the electroless nickel deposit. Those 

deposits plated from baths containing heavy metal and sulfur-bearing brighteners 

and stabilizers, such as most commercial low- and mid-phosphorus electroless 

nickel systems, form a thicker tenacious passive layer than those that do not, 

such as most high-phosphorus electroless nickel systems. High-phosphorus 

electroless nickel systems tend to be more solderable in aged deposits.



Other important factors influencing the solderability of electroless nickel 

deposits include residual contamination left on the surface after plating and 

storage conditions after drying. Surface contamination and exposure to 

environments containing sulfur dioxide, chlorine, high humidity and high ambient 

temperatures will detrimentally affect solderability. Therefore, it is 

imperative that parts be thoroughly rinsed in clean DI water, dried and stored 

in a cool, dry atmosphere, preferably nitrogen.

This article indicates high phosphorous plating is best for long term 

solderability, and also that parts must be stored carefully (cool, dry, sealed, 

nitrogen).  Other articles seem to state this is a highly stable finish and is 

even used as a corrosion inhibitor.



Thanks,





Kevin Glidden

Manufacturing Engineer

Astronics Luminescent Systems Inc.<http://www.astronics.com>

4 Lucent Drive

Lebanon, NH 03766

(603) 643-7766 x3152



Please note, LSI operates on a 9/80 work schedule, and is closed on alternating 

Fridays.  Please click the link provided to view the days LSI will be closed.

http://www.astronics.com/LSI/documents/2010calendar-NH.pdf



NOTICE: This communication is intended specifically for the recipient(s) named 

above and may include proprietary, confidential or privileged information. If 

you are not a named recipient, you should immediately delete or destroy all 

electronic and physical copies of this communication. Unintended recipients also 

should not utilize, repeat, publish or relay to any other person the information 

contained herein nor should they take any action based upon, in whole or in 

part, such information. If you have received this message in error, you are 

requested to contact the sender immediately.



EXPORT COMPLIANCE STATEMENT: The information contained herein is or may be 

controlled by the International Traffic in Arms Regulations (ITAR), 22 CFR 

120-130, or the Export Administration Regulations (EAR) and may not be exported, 

or disclosed to a foreign person, whether in the United States or abroad, 

without prior U.S. Government and Astronics Luminescent Systems written 

approval. Violations of these regulations could result in administrative, civil 

or criminal penalties.  If you have any questions about the nature of the 

material contained in this email please contact the sender immediately.





______________________________________________________________________

This email has been scanned by the MessageLabs Email Security System.

For more information please contact helpdesk at x2960 or [log in to unmask] 

______________________________________________________________________



---------------------------------------------------

Technet Mail List provided as a service by IPC using LISTSERV 15.0

To unsubscribe, send a message to [log in to unmask] with following text in

the BODY (NOT the subject field): SIGNOFF Technet

To temporarily halt or (re-start) delivery of Technet send e-mail to 

[log in to unmask]: SET Technet NOMAIL or (MAIL)

To receive ONE mailing per day of all the posts: send e-mail to 

[log in to unmask]: SET Technet Digest

Search the archives of previous posts at: http://listserv.ipc.org/archives

Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for 

additional information, or contact Keach Sasamori at [log in to unmask] or 

847-615-7100 ext.2815

-----------------------------------------------------


 

______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

ATOM RSS1 RSS2