There look to be pros and cons with RoHS compliant PCB options for plating and soldering I've looked into. I'm not sure how real the tin whisker problem is or if it's more of an older problem that's been resolved by better solder compositions.
The priorities for this discussion are reliability of solder joint (electrically speaking and bonding over temperature and vibration) followed by price. The PCBAs will be conformally coated with acrylic coating.
What is the recommendation for PCB plating and solder for this scenario? It looks like tin solder on gold immersion is good, but are the 2 different metals going to interact, especially over time? Tin solder on silver immersion looks good but I don't find much data on this. Tin solder on tin immersion mentions whisker problems. Does the conformal coating block whiskers? I've heard yes and no from a few sources. I hear something about some kind of organic immersion which I can find even less about.
What are you using in high reliability RoHS compliant PCBAs?
Thanks, Bill Softools