Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

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SMT electronics assembly manufacturing forum.


Resistance Shift with Lead free

Views: 877

#39218

Resistance Shift with Lead free | 19 January, 2006

Any metalurgists out there? I take the resistance value of a metal oxide substrate made of silver or gold or manganese. I then solder with 63/37 and the resistance changes but not dramatically. I then solder with Lead free SAC305 and the resistance changes immensly. Any suggestions as to why? and or suggestion for lead free alloy that will not have this effect?

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#39235

Resistance Shift with Lead free | 20 January, 2006

Steve,

How do you measure the resistance is it by probing the surface? Concerning the alloy there is a straightforward linear correlation between the tin content and the electrical conductivity of the alloy. The higher the tin content in the alloy, the better the electrical conductivity. But if you measure resistance by surface probing, the lead free alloys oxidize significantly faster compared to leaded alloys and since tin oxide is an insulator you will see an increase in resistivity.

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KEN

#39256

Resistance Shift with Lead free | 21 January, 2006

Is it possible you are producing a Kelvin junction?

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Reflow Oven

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