That is when you'd see those black streaks in a layer of electroless Ni. Regards, Vladimir SENTEC Testing Lab On Fri, 25 May 2012 10:53:55 -0400, Robert Kondner <[log in to unmask]> wrote: Dumb Question: > > What Is "Hyper-corrosion"? > > Bob K. > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman > Sent: Friday, May 25, 2012 9:29 AM > To: [log in to unmask] > Subject: Re: [TN] Phosphorus content in Electroless Nickel > > Hi folks! Just to add a couple of details to Geoge's good details. The > general rule of thumb is that the "low P" nickels have good solderability > but can be prone to "black pad" issues and the "high P" nickels have good > corrosion resistance but can be prone to solderability issues. The > "mid P" nickels are requested by many users/designers are a > compromise for dealing > with those three attributes. And as George detailed, the P content isn't the > root cause of black pad - hypercorrosion of the nickel plating prior to > immersion gold deposition is the root cause and can be (but not always) more > prevalent with some "low P" nickel plating formulations. One thing to keep > in mind is that process control of a nickel plating chemistry is critical to > achieving the plating properties you are expecting - any of these three > types of nickel plating can be done incorrectly if due diligence is not > followed. > > Dave > > > > "Wenger, George M." <[log in to unmask]> Sent by: TechNet > <[log in to unmask]> > 05/24/2012 11:51 AM > Please respond to > TechNet E-Mail Forum <[log in to unmask]>; Please respond to > "Wenger, George M." <[log in to unmask]> > > > To > <[log in to unmask]> > cc > > Subject > Re: [TN] Phosphorus content in Electroless Nickel > > > > > > > Frank, > > 2-5% is considered Low P > 6-10% is considered Mid range P > 11-14% is considered High P > > Many of the boards we examined years ago that were fabricated with > ENIG had Mid range P. I'm not sure if I can find Zequm Mei's > original ENIG work but he first thought that P content was the cause > of BP failures since when he looked at fracture surface there was > always high P content. However, you can't look just at a fracture > surface because there will always be a high P content because at the > interface you consume some Ni during the IAu processing and then more > again during soldering. So you might have a Mid range P ENIG but at > the fractured surface it may look like High P. Since then there has > been lots of information indicating that P content isn't the root > cause for BP. I think I have the final HP paper on ENIG that Sequm > was one of he authors and can send it if I find it. > > > Regards, > George > George M. Wenger > Senior Principal Reliability / FMA Engineer > Andrew Corporation - Wireless Network Solutions > 40 Technology Drive, Warren, NJ 07059 > (908) 546-4531 Office (732) 309-8964 Mobile > E-mail: [log in to unmask] > > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Frank Kimmey > Sent: Thursday, May 24, 2012 12:22 PM > To: [log in to unmask] > Subject: [TN] Phosphorus content in Electroless Nickel > > I know this may be difficult to commit to but what would you consider > an acceptable percentage of Phosphorus in Electroless Nickel. > I am being asked to accept 7-10% and am not sure if this may lead > towards Solderability issues. > Feedback from Chemists, Board Fabricators or anyone with an opinion > is appreciated. > Thanks to a great group of minds, > FNK > > Frank N Kimmey CID+ > Manager - PCB Design > Powerwave Technologies Inc. > Mobile - 916-670-0645 > > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud service. > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud service. > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ > > > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud service. > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ > > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud service. > For more information please contact helpdesk at x2960 or > [log in to unmask] > ______________________________________________________________________ > > ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. 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