Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Electroless Nickel without gold immersion

#21245

Electroless Nickel without gold immersion | 20 August, 2002

Has anybody expierianced solderability issues on electroless nickel boards that do not have gold immersion? We recently tried to process boards of this type, and I may as well have been trying to reflow on plastic. Any ideas?

reply »

#21248

Electroless Nickel without gold immersion | 20 August, 2002

Haaaaa!!!! Soldering to plastic!!!! An apt analogy!!! I like to compare it to soldering to dirt. Some thing.

In fact, you are soldering on nickel, when soldering on many things. It�s just that the gold, er Pd, flash enables the wetting mechanism between the solder and the nickel by protecting the nickel from corrosive crowd.

We have been soldering on nickel-plated parts for many years and if treated correctly, wetting is good enough. But, one can't put the process into hands of amateurs. Nickel needs a longer time for obtaining maximum wetting. Probably needs to be in N2 cabinets. If it's naked, it must not be touched. It needs a good process setup, before production. I wouldn�t dream of buying nickeled parts from an unknown, possibly make it yourself or have a very skilled supplier.

Oxidized nickel is difficult to solder, because age, storage conditions, and general condition of the solderable surface affect your ability to wet. About soldering to nickel, Manko says: * Electrochemical: Fairly easy to solder, may require a more active flux. * Electroless: Phosphorous is difficult to control. [The P co-deposits with the Ni.] So, high P, GT 5-7% [others say GT 8%], makes it difficult, if not impossible to solder. [This is the �black pad� problem when soldering to ENIG boards.]

If you want to solder to nickel, you need a flux that is not afraid in a knife fight. These mamby, pamby NC fluxes and most water washables are going to roll-over on their backs and try to get the nickel to scratch their bellies. Certainly, using a flux like that is not without its hazards. Clean-up requires attention to detail.

Choices, choices: * Use a VERY active flux to solder nickel, such as an amine hydrochloride activated water-soluble type, of course followed by a squeeky clean wash. * Bag the eenie boards and get normal with ENIG.

reply »

Kevin Facinelli

#21259

Electroless Nickel without gold immersion | 21 August, 2002

Dave,

I am interested in a amine hydrochloride activated flux. Can you give suggestions on readily available fluxes that you have used that have strong deoxidization properties. I am looking at something that could be used in a pinch when the standard fluxes just don't standup. I am looking for specifics (Vendors, Product Names) so if you prefer to email me directly that would be great.

Thanks,

Kevin

reply »

#21266

Electroless Nickel without gold immersion | 21 August, 2002

Your flux supplier will have good suggestions.

reply »

SMT in-printer dispensing