Victor,
I can't seem to find my "galvanic metal" chart. It lists metals, in order of their corrosive reactions with each
other.
Silver, I believe, is at one end of the chart. This means it will react with virtually any other metal, except the
nobles (gold etc.)
In addition both tin and silver will oxidize.
Silver oxides do conduct but they can create uneven surfaces thus reducing current carrying capabilities.
Tin oxides do not conduct thus they increase the contact resistance. This increases the voltage drop, power (heat)
dissipation increases, and a catastrophic failure can occur (smoke!!).
Even gold to gold contacts can fail if the gold is worn through and the underlying nickel is exposed. I have seen
connectors explode from this. Granted they were on 30 kW generators, but I have also seen hot spot damage on boards
and connector fires in cars for the same reason.
Your combination is a lawsuit in progress!!!
David A. Douthit
Manager
LoCan LLC
Victor Hernandez wrote:
> To Phil and David,
>
> You state " DIS SIMILAR " metals can cause a failure.
> This is what I am inquiring about. No being a true metallurgist.
> How can I find out if base material/nickel/tin is an ACCEPTABLE plating.
> Is this a KNOWN problem COMBINATION that I should be ALERTED too.
>
> victor,
>
> -----Original Message-----
> From: Crepeau, Phil [mailto:[log in to unmask]]
> Sent: Wednesday, September 18, 2002 12:09 PM
> To: [log in to unmask]
> Subject: Re: [TN] Contact Plated Finish
>
> i would like to say 'amen' to this. unless you think living on the edge is
> some kind of virtue.
>
> phil
>
> -----Original Message-----
> From: David Douthit [mailto:[log in to unmask]]
> Sent: Tuesday, September 17, 2002 5:25 PM
> To: [log in to unmask]
> Subject: Re: [TN] Contact Plated Finish
>
> Victor,
>
> Dissimular metals used for contacts is very seldom a good idea.
>
> The "lowest bidder" concept, in this case, could result in catastrophic
> failures.
>
> Gold to gold is, particuarly for power contacts, is by far and away the best
> match!
>
> David A. Douthit
> Manager
> LoCan LLC
>
> Victor Hernandez wrote:
>
> > Fellow TechNetters,
> >
> > Does anyone known if this combination of plated surfaces will create a
> > problem.
> > Male Pin Female pin
> > 1). Contact pin: base material/Nickel/Tin Contact Pin: base
> > material/silver
> >
> > application on a power connector.
> >
> > Victor,
> >
> >
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