Bob,
If Bi were a human toxicity concern, then there would be a lot of dead people that chug Pepto-Bismol!
The environmental concern is that, depending on geographical location, a significant proportion of the world's bismuth is obtained as a by-product of lead mining. So if we want more bismuth and do not buy more and more of it from the Chinese, who are getting it as a by-product from their tungsten mining, then we are going to have more lead tailings, dust, etc. than we have now!
The main concern regarding bismuth for most of us in the industry is solder joint reliability - IF the amount of bismuth is high enough. Look at the Boeing papers. They show the tin bismuth alloy that is close to 50/50 is death with lead, but some of the others that have < 10% bismuth if contaminated with less than 1% lead aren't so bad.
regards,
Bev Christian
Research in Motion
-----Original Message-----
From: Barr, Bob [mailto:[log in to unmask]]
Sent: January 22, 2004 1:07 PM
To: [log in to unmask]
Subject: Re: [TN] Lead-free Component Finishes
Re: Bi,
I am a little surprised to see Bi as a leading candidate. At a seminar I
attended, the subject of Bi in solder was discussed. I thought I heard that
Bi was meeting resistance, especially in Europe, because the environmental
issues with it were worse than the lead it was replacing. Not being a
chemist, I don't know which is worse from a landfill toxicity viewpoint -
2%Bi or 37%Pb. It is also quite possible I misunderstood what was said about
Bi! Is Bi as a component of solder an environmental concern?
Thanks.
=========================
Bob Barr
Manufacturing Engineering
Formation, Inc.
=========================
> -----Original Message-----
> From: Leo Higgins [mailto:[log in to unmask]]
> Sent: Thursday, January 22, 2004 12:07 PM
> To: [log in to unmask]
> Subject: Re: [TN] Lead-free Component Finishes
>
>
> In Japan most companies are moving towards Sn-Bi lead
> finishes (typically
> Sn-2Bi), ...message snipped...
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