Nigel, The usual cause of poor solderability of Au over Nickel is passivation of the nickel. The most common reason for this - assuming boards are not out of time - is the Au being too thin or porous. The next most common is the nickel is already passivated at the time of application of the Au. [Keep in mind the Au plating does not enhance the solderability of the Ni, the best it can do is keep the Ni in the same condition as when it was applied. The worst it can do is to shield the Ni from any attempts to correct the problem.] In either case I am not sure what you can do, other than to understand your supplier's problems. At the risk of sounding a little harsh why do you want to take this problem on anyway? The boards are either to your specification and functional requirements or they aren't. You naturally have a spec which calls out optimum plating thicknesses and you have a solderability test included to ensure functionality, so what do you need to do if work is found to be out of spec or non-functional and non-correctable? Mike ----- Original Message ----- From: "Burtt, Nigel" <[log in to unmask]> To: <[log in to unmask]> Sent: Monday, November 27, 2000 10:16 AM Subject: [TN] Ni/Au solderabilty > Anyone out there got more than their fair share of problems with > solderability on PCBs with electroless Ni/Au surface finish at the moment? > > We have had problems before from a supplier, with Ni/Au boards poorly dried > after the final rinse and others with copper contamination in the acid clean > bath, but this looks like it might be a new cause. Phosphorous content does > not seem to be relevant. > > Thanks > > > Nigel Burtt --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------