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).
At extremely high temperatures (200-250Â°C) aluminum alloys tend to lose some of their strength. However, at subzero temperatures, their strength increases while retaining their ductility, making aluminum an extremely useful low-temperature alloy. Aluminum alloys have a strong resistance to corrosion which is a result of an oxide skin that forms as a result of reactions with the atmosphere.