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Alternatives to Lead plating

May 13, 2011

Q. Hello,

I am trying to get away from Lead(Pb) plating because of cost and RoHS.
It is a washer made out of Copper and plated with Lead (Pb). This washer get squeezed under a nut between two surfaces. While Copper get squeezed, along with lead (Pb) get squeezed too, which avoids copper (base material) exposure. This is a metal to metal seal.
I tried 100% Tin (Sn) plating but it failed and leaked at low temperatures. I tried Indium and it works but very expensive. I tried very odd combination 60% (Sn) and 40% (Bismuth) plating. it worked as good as Lead (Pb) plating. Application is cryogenic and steam.
Do you know any other alternatives or other combinations. Please help

Regards
Singh

Surinderpal Singh
Product designer - Lincoln Park, New Jersey, USA

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Q. I am trying to get away from Lead(Pb) plating because of cost and RoHS.
It is a washer(about 1" dia) made out of Copper (base meterial) and plated with Lead (Pb). This washer get squeezed under a nut between two surfaces. While Copper get squeezed, lead (Pb) plating get squeezed too along with, which avoids copper (base material) exposure to mediam This is a metal to metal seal.
I tried 100% Tin (Sn) plating but it failed and leaked at low temperatures. I tried Indium and it works but very expensive. I tried very odd combination 60% (Sn) and 40% (Bismuth) plating. it worked as good as Lead (Pb) plating. Application is cryogenic and steam.
Do you know any other alternatives or other combinations. Please help

Regards
Singh

Surinderpal Singh
- Lincoln Park, New Jersey, USA
August 26, 2013