Per IPC-4552 which defines ENIG plating which is what I assume you are talking about, and not ENEPIG, the phosphorus and boron content is mentioned in section 1.2.1 and within Table 3-1 it references ASTM-B-733-97 and ASTM B607-91. It depends on the plating company and the specific ENIG plating product; no specific value is given other than it should be controlled within the specific process limit, which is (usually) a function of the plating product (Technical Data Sheet) used. No testing is required. The desired range from the many papers I have read always point to an "ideal range" of 7 to 10% P, but that may have changed in the past two or three years.
Many factors other than the P-level are just as or more important, however. For example, if the gold thickness is too high it can also result in an attack on the nickel which results in a change in the P-level. If the nickel bath is less than 4% P, the general consensus is for sure it is much too acidic and will result in problems. But it all depends.....Kachink.
But whatever it is for the specific product and process used, all of the standards, documents, and papers written on the subject say the same thing; the ideal process parameters are required to be precisely identified, documented, and carefully controlled and monitored. If the plating company does not have real-time monitoring and datalogging equipment in place and being used, don't use that vendor.
dean

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Frank Kimmey
Sent: Monday, January 29, 2018 9:45 AM
To: [log in to unmask]
Subject: [TN] Phosphorus content in Electroless Nickel

Hey FAB Guys (or Chemical types or anyone else who might help), What should the P content in the Electroless Nickel bath be?
I am concerned some of our suppliers are running to high.
This could be the cause of some Brittle Fracture failures I have been seeing.
What would you consider a good range for Phosphorus percentage in the Electroless Nickel bath?
Thanks,
FNK

Frank N Kimmey CID+
Electrical Engineer / PCB Design
VeriFone Inc
1400 W Stanford Ranch Road, Suite 200
Rocklin, CA 95765 USA
W: 1-916-625-1818
M: 1-916-833-9877
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