As an automotive supplier, we have been dealing with the hazardous material
restrictions in the ELV (End of Life of Vehicles) for long enough to see the
writing on the walll in RoHS and it is not pretty.
In the original ELV (DIRECTIVE 2000/53/EC) there was a specific exemption
which allowed for CR VI as corrosion protection up to 2 grams per vehicle.
12. Corrosion preventative coating on numerous key vehicle components
(maximum 2 g per vehicle)
The revised exemption list (2002/525/EC) requires elimination of
intentionally added CR VI by 2007. If not intentionally added, up to 1000
ppm per homogeneouis material is allowed.
_________
Notes from the revised Annex II of the ELV:
- a maximum concentration value up to 0,1 % by weight and per homogeneous
material, for lead, hexavalent
chromium and mercury and up to 0,01 % by weight per homogeneous material for
cadmium shall be tolerated,
provided these substances are not intentionally introduced (1),
(1) "Intentionally introduced" shall mean "deliberately utilised in the
formulation of a material or component where its continued presence is
desired in the final product to provide a specific characteristic,
appearance or quality". The use of recycled materials as feedstock for the
manufacture of new products, where some portion of the recycled materials
may contain amounts of regulated metals, is not to be considered as
intentionally introduced.
__________
As written and based on the guidance documents available so far and the
reported modeling of RoHS after ELV, If you are intentionally adding CR VI,
it will be illegal to sell it in the EU after July of 2006.
I suppose on the bright side, it helps reduce the concerns about long term
reliability of the lead free solder joint if the rest of the device is
corroding..........
__________________________________________
Dan Kallin Environmental & Safety Engineer
Bose Corporation Framingham, MA 01701
[log in to unmask]
508-766-7136 (phone)
508-766-7086 (fax)
__________________________________________
-----Original Message-----
From: Jerome Wagner [mailto:[log in to unmask]]
Sent: Friday, February 20, 2004 4:29 PM
To: (Leadfree Electronics Assembly Forum); Kallin, Dan
Subject: [LF] Chromate conversions
Dan: This is exactly the scenario or chain-of-logic that I am concerned
about! as it leads to the conclusion that any residual CrVI in the
treatment layer could be deemed illegal!
jw
Jerry Wagner Dept 0056 Environmental Engineering B096-1
x56275 pg 58888-0658 (607)755-6275 fax: (607)755-6282
Huron Real Estate Associates, LLC and Endicott Interconnect Technologies,
Inc.
Via the Internet: [log in to unmask] [NOTES: Jerome Wagner/Huron/EIT]
The automotive customers compliance with ELV requires us to eliminate the
use of Hex chrome coatings pretty much across the board. Perhaps this will
be clarified or improved when "homogeneous material" is clarified, but if
they follow the lead of ELV (Which I have heard they are doing) the coating
would be considered the homogeneous material and therefore the 1000 ppm
would apply to the coating, not the coated part.
Clearly it is intentionally added as well, so the 1000 ppm limit probably
would not apply either.
__________________________________________
Dan Kallin Environmental & Safety Engineer
Bose Corporation Framingham, MA 01701
[log in to unmask]
508-766-7136 (phone)
508-766-7086 (fax)
__________________________________________
-----Original Message-----
From: Brian Ellis [mailto:[log in to unmask]]
Sent: Friday, February 20, 2004 10:26 AM
To: [log in to unmask]
Subject: Re: [LF] Chromate conversions
I don't understand the problem. Chromate conversion coating is usually
about 1 µm thick. Less than 1/3 the weight of zinc chromate is chromium.
The density of ZnCrO4 is roughly 1/2 that of steel. So if your steel is
more than 0.33 mm thick (assuming both sides are conversion coated),
then you will be under the 0.1% limit for flat surfaces. As hardware
with a convoluted surface, such as screws, is usually pretty bulky, I
see no problem there. You could always weigh your parts, chemically
dissolve the conversion coating and analyse to determine the weight of
chromium: I'll bet a pound to a penny that very few items (very small,
thin, convoluted parts) would exceed your 0.1%.
If you have transparent, colourless, chromate conversion coatings, these
must be very thin (less than 1 µm). Zinc chromate is a quite deep and
intense yellowish colour.
If you're still scared, there are other conversion coatings, such as
oxidation and phosphatation.
Brian
to Paul Taylor wrote:
> Dear All
>
> this question is a more RoHS orientated, however it is associated with
> metallurgy, I'm a bit confused as I'd not heard of it before.
>
> What chromate conversions involve Hexavalant Chrome (this applies to
> fixings, screws etc). I've been told that both the Nickel Plate and
> Zinc Chromate platings use Hexavalant chrome. Is this true? or have I
> been miss-informed.
>
> The issue fo us especially concerns steel parts that have a zinc
> chromate finish. This is also known as zinc clear and /or zinc clear
> chromate. The problem is that this process results in the part having
a
> coating of Hexavalent VI chrome. I am not a metallurgist, but have
been
> informed that when tested, the directive of having no more than 0.1%
by
> weight will be exceeded, by parts large in surface area.
>
> regards
>
> Paul
> Paul R Taylor
> Technical Advisor
> Pitney Bowes Ltd email: [log in to unmask]
>
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