Dave and Victor,
here is the galvanic series. Make sure all selections are comply with the
rules. Otherwise, you may end up pay lawyers instead engineers. I am sure
you can calculate the salary difference based on hourly basis (how come the
MBA never know that? ;-).
http://www.corrosionsource.com/handbook/galv_series.htm
jk
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]]On Behalf Of David Douthit
>Sent: Wednesday, September 18, 2002 8:11 PM
>To: [log in to unmask]
>Subject: Re: [TN] Contact Plated Finish
>
>
>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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