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SMT electronics assembly manufacturing forum.


Ni/Sn plated parts

#29102

Ni/Sn plated parts | 14 June, 2004

Is any one else having a problem with parts that are Ni/Sn plated? The parts in question are a 1206 voltage suppressor form AVX. I am still using a stander 63/37 solder paste which is according to AVX�s web sight compatible with this plating. The problem I am having is that after reflow there is a good looking solder joint on the components but if they are probed they fall off.

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RDR

#29104

Ni/Sn plated parts | 14 June, 2004

How old are these parts? Sn/Ni plating is very succeptable to age and everything else. They are possibly tarnished. Also, what is your peak temp in reflow? It takes about 225 230 C to get good wetting to the underlying nickel.

Russ

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#29113

Ni/Sn plated parts | 15 June, 2004

The parts are dated Mar 20 2004. My profile hits a peek of around 232-240c and is above 225 for around 30 seconds.

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RDR

#29119

Ni/Sn plated parts | 15 June, 2004

Well take away the easy answers! How are the parts falling off? Is the joint breaking the termination on the part or is it breaking at the solder to termination interface? Also, how long are these parts in liquidous state? and what type of paste are you using.

Russ

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#29122

Ni/Sn plated parts | 15 June, 2004

It seems like the break is happening between the sn and ni. The parts are dull in appearance will not take solder even with an iron after they come off so it leads me to believe that there is only ni left on the part. The parts are liquidous for about 60 seconds �above 183 C�. The solder paste is from Amtech and us the NC-559 V2 type 4 89.5% metal 63Sn/37Pb.

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RDR

#29141

Ni/Sn plated parts | 16 June, 2004

have you tried a more agressive flux like water soluble to see if the problem goes away? Or can they be hand soldered with no problem? I am basically out of ideas other than a bad nickel or tin finish. The reflow profile didn't seem out of whack from what I can tell. I wouldn't know if a type 4 paste would contribute to this issue, hopefully someone else can tell us. Where's Dave F when you need him?!

Russ

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#29143

Ni/Sn plated parts | 16 June, 2004

I ran some test samples with a water soluble past (Amatech ws488). I also tried hand soldering using an Alpha ws375 wave soldering flux and some old fashioned RMA. The results are pretty much the same. Some of the joints look a better that others but ultimately with a mild amount of force, the parts can be popped off of the boards. The really disturbing thing is that I have tried some plated parts from a different manufacture (KOA) and I have the same problem. We have not used a lot of the plated parts and I am wondering if that is just the way they are. I have put down some of the old parts that we had in a dump bin that have the SN\PB ends and the part breaks in half (with a great amount of force) and the ends of the part are sill in the solder.

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RDR

#29148

Ni/Sn plated parts | 16 June, 2004

Well I am clueless! I have a lead free build coming up and I am going to check to see if our parts do the same thing. I will let you know.

Russ

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#29154

Ni/Sn plated parts | 17 June, 2004

It sounds like the parts are not soldering properly [have poor solderability]. This probably due to corroded nickel underplate caused by: * Nickel that oxidized, while awaiting overplating * Poor quality tin overplate, allowing nickel to oxidize after overplating

Consider: * Working with your supplier to replace these parts. * Recalling finished [semifinished] product assembled with these parts.

Russ: Earlier in this thread, you suggested switching to a water soluable flux. We have used nc fluxes that were far more aggressive than the flux in good old WS609 water washable paste.

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