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).
Stainless steel. Stainless steel is an alloy made from combining chromium into iron. The chromium content is generally between 10.5% to 30%. Other alloying elements like nickel, molybdenum, copper, titanium, aluminium, silicon, niobium, and nitrogen are added to enhance specific characteristics of stainless steel.