RoHS compliant plating queries 1

[nigelt]

Thanks in advance for any reponses.....
First: I am interested on any comments on RoHS compliance of Electroless Nickel plating. I'm generally thinking of metal substrates, typically Copper alloys. I am vaguely aware that there are different varieties of electroless nickel process, are some questionable in terms of compliance?
Second: what about zinc precoated steel for brackets, chassis etc. No problem there, right?
I don't imagine either are problematic, but I'd appreciate any input.
But the old zinc plate & clear or yellow chromate is out, eh?
Cheers,
Nigel

Don't ever! Don't ever, ever, ever dumb it down!
with apologies to Sir W. Churchill

 

[kenvlach]

RoHS compliance can be a problem with electroless nickel (EN), as small amounts of Cd or Pb are often used as brighteners. What's insidious is that the concentration may be low enough (<10 ppm) that the Cd or Pb isn't listed on the MSDS, but it can preferentially deposit to above 1000 ppm (0.1 wt%) in the EN plating. Check with the EN chemistry supplier, Atotech, Enthone, MacDermid, etc. [see below] whether a particular EN bath produces RoHS-compliant coatings.

Substrates: Lead is found in many free-machining alloys, e.g., Al 2007, Al 2011, Al 2030, 12L14 steel.
Too many Cu alloys to list, you can access at

http://www.copper.org/resources/properties/homepage.html

Also,
Cu casting alloy compositions:

http://www.coppercanada.ca/publications/pub13e/13e-Section9B.html

Leaded coppers:

http://www.copper.org/resources/properties/microstructure/cu_leaded.html

Leaded brasses:

http://www.copper.org/resources/properties/microstructure/lead_brasses.html

Galvanized (hot dipped) compliance depends upon the supplier. After coating, the galvanized steel is often quenched in a 0.5% hex. Cr bath; this helps prevent 'white rust' and other corrosion during shipping & storage.

Electroplated & mechanically plated zinc, ZnFe, ZnNi, etc., are often given a clear (bright etch, slightly blue), blue, olive or yellow chromate for corrosion protection & coloration. Traditionally hex. Cr, but many trivalent Cr coatings are available. Some require supplemental sealing to match the salt spray resistance of hex. Cr. Depends upon the supplier.

For more info:

http://www.finishing.com/

http://www.metalfinishing.com/

http://www.pfonline.com/

http://www.atotech.com/start.php3?cl_my_id=675813

[Electroless Nickel]

http://www.atotech.com/data/Atotech USA/Corrolux_USA_PDF.pdf

[Hex. Cr-Free Treatments for Zn]

http://www.enthone.com/functional/index.aspx

[index of many products. Notes which EN are RoHS compliant, also lists trivalent chromates & sealants for Zn]

http://www.macdermid.com/industrial/pdf/NikladELV.pdf

[Cd- & Pb-free EN solutions]

 

[nigelt]

Thank you for your generous reply to my question. It will take some time to digest!
Much appreciated.

This issue may have to be covered by a general note on the drawing, that calls for certificate of RoHS compliance be available for almost any material or process. The reason I say this is, clearly while one may intuitively "know" that a certain matl would not fall into the list of non-compliant "stuff", there are so many pitfalls vis-a-vis residues from processes, %'age alloying elements, different suppliers for the same process, etc etc, that it will be very difficult to state catagorically that ones product is compliant.

Anyone got any thoughts or actions they have taken to effect this? I work for a small company, so resources are limited.

Cheers!

Don't ever! Don't ever, ever, ever dumb it down!
with apologies to Sir W. Churchill

 

[alexit]

I am in charge of our RoHS efforts and have found these materials in very odd items. We are currently stepping in a big mess due to measurable traces in alloys, plastics, even some paints use enough to be uncertain (how accurate is the colors mixed to guarantee that NEXT time they would be <100ppm?) Of course your part size may make a difference there. (Hey Bob why is this cover 5mm thick? So when we mold it in Flaming Red PC the cadmium doesn't exceed 100ppm!)

Our choice was notes on the drawings, requiring certs, and testing whenever we had a doubt.

Our company is not too big but the outside consultants we've found have trouble with difference between donkey and elbow when talking about RoHS...even some of the European ones we met with. You are not alone, but it seems that you are going at it alone.

 

[nigelt]

Thanks alexit,
As I suspected, we can choose to get obsessive (and fatten up the consultants) or we can write motherhood statements on our drawings (and let the devil take the hindmost). As always, the pragmatic course is somewhere in between!

Your approach seems reasonable:
1 Educate (can you suggest any handy resouces? I found a ground level primer at

http://www.newark.com/services/rohs/#step1

2 State (on drawings)
3 Certificate (from suppliers)
4 Confirm (by means of a QC testing with some kind of tolerance or reasonable historical statistical % inside/outside the limits, perhaps)

Don't ever! Don't ever, ever, ever dumb it down!
with apologies to Sir W. Churchill

 

[alexit]

Best site I've found is:

http://www.rohswell.com/

I wish they had a forum for discussion though...

 

[kenvlach]

Another good site is IBM's 'Platings, Anodizings, Coatings' table. It tells which processes are (Not RoHS Compliant), and the RHS column lists specific chemicals (Supplier, brand, name, color). Especially good for different trivalent chromates & seals for zinc plating.

It also includes trivalent chromium plating solutions, not required for RoHS but very relevant for platers' health & US OSHA.

https://bomdetail.services.ibm.com/matcodes/matcodes.nsf/pages/mat41.htm