Flex PCB Assembly

Right now, the Flex PCB Assembly finish is ENIG: Nickel thickness is 2-4um (78-156uin) and gold thickness is 0.03-0.05um (1.18-2uin). There is potential for salt water to enter the device and create a 'pool' of salt water around the rubber contact / pad which causes corrosion of the pad. There is potential for 36V to be on one of the contact with a very low current (a couple of milliamps).

The Flex PCB Board takes in salt water (not immersed, sprayed onto the enclosure) and the pads that the conductive rubber contacts sit on get corroded . This is the area where the salt water gets into when the user sprays the outside enclosure. There is an external object with gold contacts that gets placed in these contacts and the user then sprays salt water onto the object. There is potential for the salt water to get through the contacts and onto the flex pcb. Through these contacts, there could be up to 36V (2mA).