What a quagmire. I think I need about a year to try to read and decipher
the legalese and technical requirements. There are many businesses out
there offering consulting services to help guide companies through this
mess. Has anyone used any of them and felt it was worth it?
I am not asking for solicitations...we've had several already, just trying
to get a feel for their worth. Responses to this question might be best if
they are sent to me off line, especially if you name specific names.
Thanks.
-----Original Message-----
From: James, Chris [mailto:[log in to unmask]]
Homogeneous is understood as "of uniform content throughout" which
anodising is obviously not and could therefore be separated by a
grinding or abrasive process.
Regards,
Chris
> -----Original Message-----
> From: Leadfree [mailto:[log in to unmask]]On Behalf Of Brian Ellis
>
> Re aluminium:
>
> 1. Anodisation. It is true that chromate baths may be used,
> but sulfuric
> acid is more common, to prevent staining (there is always a slight
> yellowish cast with chromate anodisation). However, the rinsing (which
> may be incomplete) should be followed by a sealing process,
> even if the
> metal is not pigmented/dyed. This is usually done by 30 minutes in
> boiling water and would remove most residual absorbed chromates.
> Nevertheless, there may be trace quantities of chromates
> encapsulated in
> the oxide coating but which cannot escape. I suggest that
> these become a
> homogeneous part of the aluminium, as the oxide coating is harder than
> the aluminium itself and cannot be removed, even chemically, without
> damaging the aluminium itself. It would therefore seem unlikely that
> this would fall under RoHS rules.
>
> 2. Conversion coating. This is another kettle of fish and CC
> is applied
> to a whole host of other metals, as well as aluminium, especially zinc
> and cadmium platings. There are different formulae, some of
> which form a
> process called chromatisation. These form an extremely thin layer of a
> complex of metal oxides with small amounts of metal
> chromates/chromites,
> the primary purpose of which is to prevent metal staining by
> fingerprints and minor corrosion. However, the protection is fairly
> minimal. As the coating is ultra-thin (a few monolayers
> thick), it would
> seem unlikely that the >0.1% rule could be evoked. There are many CC
> formulations that do not involve chromatisation and most surface
> treatment companies tend to avoid chromates nowadays because of water
> treatment problems with chromate complexes.
>
> Be warned: black aluminium radiators for semiconductors may use either
> process. With anodisation, the black dye is sealed into the oxide
> coating and cannot be removed, except mechanically with brute force.
> With CC (cheaper products), the black dye is applied after coating
> without major rinsing. It is easily removed, at least
> partially, either
> by rubbing with a hot water-wet cloth or by immersion in hot
> water with
> agitation for some minutes, especially with saponifiers!
>
> Brian
>
> Ofer Cohen wrote:
>
> > Everyone should look into his/her bag:
> > * Cadmium is being used for plating connectors that are
> intended for use uin harsh environments
> > * PBB and OBDE may be found in plastic materials as fire
> retardants (not so much, if at all, in PCB).
> > * Hexavalent chromium is in wide use in Aluminum plating
> (Anodize) and in smaller amount in Iridite (does any one know
> how much? I couldn't find it)
> >
> > Regards
> > Ofer Cohen
> >
> >>-----Original Message-----
> >>From: Leadfree [mailto:[log in to unmask]]On Behalf Of Genny Gibbard
> >>
> >>
> >>Almost all of the electronic industry emphasis connected
> with the RoHS
> >>directive has been on removing lead. But there are other
> >>substances listed
> >>as well in the legislation. What types of material or
> >>components might be
> >>hiding some of these other things that I might have to watch
> >>out for in this
> >>industry? I don't want to find out after going lead free on
> >>a product that
> >>it might still be refused access because of some other
> >>seemingly minor part
> >>of the product, like a weld holding the chassis together,
> or finish on
> >>metalwork, or the plastic housing of a power inductor. I am
> >>not familiar
> >>with the uses of these other substances listed below. How
> >>prevalent is PBDE
> >>in PWB material?
> >>
> >>mercury, cadmium, hexavalent chromium, polybrominated
> >>biphenyls (PBB) or
> >>polybrominated diphenyl ethers (PBDE)
> >>
> >>Thanks.
> >>
> >>
> >>Genny Gibbard (mailto:[log in to unmask])
> >>
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