Gene
This kind of response is considered unsuitable for this netlist. Please make sure that you reply only to
individuals and not to the list if you wish to promote your products.
Brian
Gene Felder wrote:
> Might want to review Desco Statshield(r) ESD Metal In Bag which has
> superior cleanliness.
>
> The film is made from an extrusion lamination process which uses no
> solvent- based adhesives that could later outgas; so minimizes bag
> contaminating product. Specifically design to meet need when circuits on
> boards use silver based alloys and not lead based.
>
> See www.desco.com at http://www.desco.com/premiumstatshieldbag.htm
>
> NVR <1.0 cm2
> Ionics <10 ng/cm2
> Outgas <500 PPM
>
> No charge sample available; just request S12758 at
> http://www.desco.com/sample.htm
>
> Consider us a source for ESD control information; we can be your ESD staff.
> Just email issues to [log in to unmask]
>
> Gene Felder
> [log in to unmask]
>
> -----Original Message-----
> From: Brian Ellis [SMTP:[log in to unmask]]
> Sent: Tuesday, June 04, 2002 11:17 PM
> To: [log in to unmask]
> Subject: Re: [TN] Oxidation problem in Silver plated components leads
>
> I'll add a little grist to the mill.
>
> Latex is vulcanised with sulfur to form rubber. Rubber bands, car tyres
> and self-adhesive tapes have one thing in common: rubber (the last-named
> is a mixture of rubber, unvulcanised latex, resin and low-volatility
> organic solvents). Copper also sulfidises, albeit less readily than
> silver. Many decades ago I directed a PCB manufacturing plant. Each
> sheet of incoming laminate was enveloped in a thick polyethylene bag, to
> which was stuck, on the outside, a small self-adhesive label, giving the
> essential data of the contents (glass style, laminate thickness, Cu
> thickness, date of manufacture and so on). Inevitably, the copper under
> the label was blackened with sulfide, despite 0,1 mm of intervening
> polyethylene. This just goes to show how poor polyethylene is as a
> protection: it is a sieve!
>
> It is not clear from Charles' post whether the rubber bands were inside
> or outside the polyethylene but I suggest it would have made no
> difference over the long term (say a month or two).
>
> Silver chloride is less of a problem because it is easy to reduce it
> back to elemental silver: just expose it to strong light, especially in
> the UV! This can be accelerated in a reducing atmosphere (e.g., 2AgCl +
> H2 > 2Ag + 2HCl). This was found out by Messrs Niepce, Daguerre, Fox
> Talbot, Lumiere and brother and Eastman about twice as many decades ago
> as I am old (and that gives my age away!)!
>
> Brian
>
> "Karnwal, Pankaj" wrote:
> >
> > Dear all
> >
> > hello
> >
> > We are facing a problem that the leads of components getting
> > tarnished(oxidized) in store only those which are the silver plated like
> BNC
> > connectors , bridge rectifiers, LED's etc. all are through hole type. The
> > humidity Laval varies 43 to 47 % .Is this is sufficient, Pls. suggest
> the
> > special storage for these components .Is this problem comes by defaults
> ?
> > and any method about the oxidized once re - using ?. Thanks in advance
> for
> > your any response.
> >
> > With regards
> > Pankaj Karnwal
> > Quality Assurance
> > BESL NOIDA
> > PH .91-120-4420394-5 EXTN.211
> > e mail : <mailto:[log in to unmask]>
> > Barco, innovators in image processing
> >
> >
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