# Tin-lead and nickel plating outlawed in the US?

J

#### Joerg

Jan 1, 1970
0
Hello Folks,

Got a big project done and goes into fab now. A surprise just popped up
where the turn-key fab house said they can't get boards tin-lead plated
and nickel-plated anymore. So we are going with gold immersion since
some areas are mechanically contacted and thus can't have HASL. The rest
could be HASL but that makes it complicated and black-pad isn't really
an issue these days anymore.

other countries?

S

#### Spehro Pefhany

Jan 1, 1970
0
Hello Folks,

Got a big project done and goes into fab now. A surprise just popped up
where the turn-key fab house said they can't get boards tin-lead plated
and nickel-plated anymore. So we are going with gold immersion since
some areas are mechanically contacted and thus can't have HASL. The rest
could be HASL but that makes it complicated and black-pad isn't really
an issue these days anymore.

other countries?

I don't think you would have a useful gold-plated board without a
nickel barrier layer between the Cu and the Au, so I call B.S.

(AFAIUI, without a barrier, the copper atoms migrate through the few
hundred atoms of gold and do bad things in a relatively short time)

J

#### Joerg

Jan 1, 1970
0
Spehro said:
I don't think you would have a useful gold-plated board without a
nickel barrier layer between the Cu and the Au, so I call B.S.

(AFAIUI, without a barrier, the copper atoms migrate through the few
hundred atoms of gold and do bad things in a relatively short time)

Not so sure about that one:

http://www.uyemura.com/library-3.htm

There seem to be issues with lead-free solder but we won't use that.

I was puzzled in the past as well when Ni-Au was the usual process.
Whenever I requested Ni-only lately there was balking. Back in the late
80's there never were any issues with that, we did it a lot. It was
nice, you could also have parts of the chassis nickel-plated and thus

S

#### Spehro Pefhany

Jan 1, 1970
0

That page says that you can wirebond to a _heavy_ gold layer deposited
over an electrolytic gold layer directly onto copper- not quite as
good as Cu-Ni-Au, but acceptable.

Again, AFAIUI, heavy gold is not great for soldering- I remember
dealing with some of the old Tek boards that had a very thick gold
layer and the solder tended to fracture easily at the interface. Flash
gold just disappears into the solder*. Even at today's bargain price
of < $1,500 USD/oz, it's also not cheap. Interesting note here: http://www.polarinstruments.com/support/cits/AP171.html ... pointing out that the usual (ferromagnetic) Ni layer causes increased losses, and that confining the nickel to selective areas such as contacts and pads can help mitigate the issue. There seem to be issues with lead-free solder but we won't use that. I was puzzled in the past as well when Ni-Au was the usual process. Whenever I requested Ni-only lately there was balking. Back in the late 80's there never were any issues with that, we did it a lot. It was nice, you could also have parts of the chassis nickel-plated and thus had no dissimilar metals problems. * years ago I did a lot of single-sided stamped boards that used an organic coating similar to liquid flux directly over the bare copper to protect it. That's how you could get a 3 x 4" board for maybe 15 cents in moderate quantities. Best regards, Spehro Pefhany R #### Robert Baer Jan 1, 1970 0 Joerg said: Hello Folks, Got a big project done and goes into fab now. A surprise just popped up where the turn-key fab house said they can't get boards tin-lead plated and nickel-plated anymore. So we are going with gold immersion since some areas are mechanically contacted and thus can't have HASL. The rest could be HASL but that makes it complicated and black-pad isn't really an issue these days anymore. Did nickel-plating become totally outlawed by now? How about Canada and other countries? You do NOT want to F with gold due to corrosion (purple plague) created by the inter-metallic potential (copper-gold) created. P #### Phil Allison Jan 1, 1970 0 "Joerg = Jerk " Got a big project done and goes into fab now. A surprise just popped up where the turn-key fab house said they can't get boards tin-lead plated and nickel-plated anymore. So we are going with gold immersion since some areas are mechanically contacted and thus can't have HASL. The rest could be HASL but that makes it complicated and black-pad isn't really an issue these days anymore. Did nickel-plating become totally outlawed by now? How about Canada and other countries? ** Nickel and tin are not " outlawed " anywhere. Lead based solder is outlawed in the EU - with exceptions for things like avionics and medical apps. 99% tin solder is the main alternative. Nickel plated connectors are used everywhere. .... Phil G #### GoldIntermetallicEmbrittlement Jan 1, 1970 0 Again, AFAIUI, heavy gold is not great for soldering- I remember dealing with some of the old Tek boards that had a very thick gold layer and the solder tended to fracture easily at the interface. Flash gold just disappears into the solder*. Even at today's bargain price of <$1,500 USD/oz, it's also not cheap.

Heavy gold is very bad for soldering, hand or machine.

It gets dissolved into the solder alloy and causes embrittlement.

Even mil contacts which have solder cups require that the assembler
fill and release the solder tinning a couple times to release any loose
gold molecules in the solder cup to tinning interface. That way, the
solder joint does not get made with gold mixed into it, since you already
suspended and released or wicked it out.

I have seen the differences and the embrittlement, and the broken
contact leads. It is a real concern. The assembly steps are required
since the contact gets plated evenly, and the desired gold thickness out
on the pin or socket itself needs to be thicker, so that means one has to
thin it in the area where the connection gets made.

J

#### Joerg

Jan 1, 1970
0
Tim said:
But Joerg, you're not in the US -- you're in California .

Seriously, I'd try other fab houses before I gave up. Or try board
vendors, and if you find one go back to the fab house and point out that
board vendor X can do it, so why can't they buy from X?

It's AAPCB the turn-key house in Colorado. They usually try a fairly
large number of PCB places.

J

#### Joerg

Jan 1, 1970
0
Robert said:
You do NOT want to F with gold due to corrosion (purple plague)
created by the inter-metallic potential (copper-gold) created.

Black pads issues? Those are long gone with controlled processes, I
think. I have solder NiAu boards a lot, worked well. On this one I have
to trust the circuit assembly house. It's a pretty big place, they
should know because they'll get the heat (and lose a contract) if it
doesn't work.

S

#### Spehro Pefhany

Jan 1, 1970
0
Heavy gold is very bad for soldering, hand or machine.

It gets dissolved into the solder alloy and causes embrittlement.

Even mil contacts which have solder cups require that the assembler
fill and release the solder tinning a couple times to release any loose
gold molecules in the solder cup to tinning interface. That way, the
solder joint does not get made with gold mixed into it, since you already
suspended and released or wicked it out.

I have seen the differences and the embrittlement, and the broken
contact leads. It is a real concern. The assembly steps are required
since the contact gets plated evenly, and the desired gold thickness out
on the pin or socket itself needs to be thicker, so that means one has to
thin it in the area where the connection gets made.

Yup.

The removal of gold from connector pins is mentioned in Procedure 7.

Best regards,
Spehro Pefhany

J

#### josephkk

Jan 1, 1970
0
It's AAPCB the turn-key house in Colorado. They usually try a fairly
large number of PCB places.

Then there is something deuced odd with this one response. Check a few
board houses, if your responses are different challenge the assembler.

?-)

J

#### Joerg

Jan 1, 1970
0
josephkk said:
Then there is something deuced odd with this one response. Check a few
board houses, if your responses are different challenge the assembler.

Well, we went with ENIG. Ni-only was not possible for whatever reason,
even though that would merely be the leaving out of one step.

S

#### Spehro Pefhany

Jan 1, 1970
0
Well, we went with ENIG. Ni-only was not possible for whatever reason,
even though that would merely be the leaving out of one step.

There's the Nicholson approach:-

Come to think of it, he never got his toast either.

J

#### Joerg

Jan 1, 1970
0
Spehro said:
There's the Nicholson approach:-

Come to think of it, he never got his toast either.

Cool. But then my client wouldn't get any boards

J

#### josephkk

Jan 1, 1970
0
Well, we went with ENIG. Ni-only was not possible for whatever reason,
even though that would merely be the leaving out of one step.

Amazing, or not. You got some short lived enviro-twit the first time.

?-)

J

#### Joerg

Jan 1, 1970
0
josephkk said:
Amazing, or not. You got some short lived enviro-twit the first time.

Reminds me of a case where some sort of zinc plating was no longer
allowed in California and we had to do it farther east. Heavy stuff, so
there were regular truck transports back and forth. Picture Diesel
plumes belching towards the sky at every steep pass when shifting gears.
Which of course in its net effect was an environmental shot into the
foot. Of course politicos cannot understand even such simple things.

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