I'm looking for a low cost contact material that can withstand being exposed to unconditioned warehouse conditions for months without the surfaces becoming corroded or oxides.
The shape of these will be similar to D cell batteries with a spring on one side and a flat contact on the other. The device is not a battery but mounts similarly and must work reliable on first install. No jiggling allowed.
The flat contact will mechanically retain a stainless steel spring (304) so this contact metal cannot react with stainless. The spring must be stainless to get the mechanical force we need. No copper or brass here.
My knee jerk reaction is to keep everything the same stainless material. The downside is the battery clip style ones need some bends and shaping that get a little expensive.
The other downside is we the minimum current passing through this contact is 1mA. Not very high to "burn" through oxided layer. We do have 15-30V so that is something but I rather not have to depend on punching through an oxide layer to get contact.
Thoughts are.
1) tinned copper or brass 2) Gold plating "LOL too expensive but maybe not in high enough batch sizes" 3) nickle plated brass, copper, tin? 4) straight tin 5) straight nickleAny other contact material/plating options stick out as a winner in this application?