Nickel phosphorus and nickel boron are two separate electroless nickels.? The electroless nickel in common usage for final finish (ENIG)?is nickel phosphorus - the reducing agent is hypophosphite.? So, you get some phosphorus co-deposited in the nickel.? Electroless nickel can also be reduced by dimethyl amino borane - DMAB.? Hence, with nickel boron, you get a bit of boron co-deposited with nickel there.? The standard writers for 4552?back in 2002?wanted to include all possible electroless nickels for surface finish use, so they put in a bit about boron.? While nickel boron has been proposed as a way to beat black pad from nickel phosphorus, nickel boron has been regarded as too expensive for practical use. 

Denny Fritz
MacDermid, Inc. 


-----Original Message-----
From: Lee Whiteman <[log in to unmask]>
To: [log in to unmask]
Sent: Wed, 27 Aug 2008 8:23 am
Subject: [TN] ENIG & BORON



Need to get educated on this one...

Was reading IPC-4552 and read that Boron and Phosphorus were used as
reducing agents. I know that too much Phosphorus (> 7%) can lead to
"Black Pad". 

Does Boron have the same effect as Phosphorus? If so, what is the UCL
for Boron in the ENIG process?

Just curious...

Thanks.

Lee Whiteman, PMP
Senior Member Engineering Staff
L-3 Communications East
Telephone: (856) 338-3508
FAX: (856) 338-2906
E-Mail: [log in to unmask]
 

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