Keep in mind that not every PCB contains all the layers listed â the need for different layer types depends on the specifics of your design. Single layer boards typically include: a mechanical layer, a keep out layer, a routing layer, an overlay layer, a solder mask layer and a solder paste layer.
An austenitic (300 series) stainless steel will outlast both aluminum and steel exposed to rain or salt spray. Steel without a protective coating will do poorly in both environments but if properly plated or painted, may last a long time. The aluminum alloys likely to be found in many consumer products may develop âlawn chair diseaseâ exposed to at least urban rain and condensation but possibly also in cleaner environments as well (up to you to test).
But this illusion can be shattered with aluminum's archenemy, mercury. Applied to aluminum's surface, mercury will infiltrate the metal and disrupt its protective coating, allowing it to rust (in the more destructive sense) continuously by preventing a new layer of oxide from forming.hen iron rusts, it forms iron oxide--a reddish, powdery substance that quickly flakes off to expose fresh metal, which immediately begins to rust, and so on until your muffler falls off. But when aluminum rusts, it forms aluminum oxide, an entirely different animal.