Stainless steel battery contact to Hasal finish pcb 1

[rossieinexile]

I curently have a sub assembley that uses a stainless steel battery contact which makes a kiss connection with a pab on a hasal finish pcb. After a period of 3 to 4 weeks there is evidence of corosion of the pad which is causing the unit not to power up.

My questions are

(1) Has any one ever used stainless steel as a battery contact.?
(2) Is hasal a suitible finish for a fixed kiss connection
for a battery contact. ( 4.5 volts)

(3) if i changed the battery contacts to nicol plated stainless steel and touched up the hasal with solder would this be a plausable rework?

 

[rorschach]

HASAL (Hot Air Solder Leveling) is a process, not a plating. You have not said what kind of plating the PCB has. Is it Tin? Gold? Nickel? Copper? Your problem is that you do not have any wiping motion. If the PCB plating is Tin or Tin/Lead, you'll have tin oxide forming on the contact. tin oxide is an insulator. If the contact had a wiping motion, the motion of the mating part would break up the tin oxide, embed it into fresh tin, and make connection (at least for a while until the surface is covered with tin oxide to a depth that no new tin can be reached by the wiping action.)a better answer, especially with voltages that low, is gold plating of the contact surfaces. Gold does not need a wiping action to prevent oxide buildup because it does not oxidize.

Stainless is a very poor conductive material. It is stainless because it forms a very thin chromium oxide layer that is protective. but that layer is not conductive. The base material is not terriby conductive either. I'd bet you are loosing a good chunk of power from resistance losses by themselves.