I will try to post a few pics that I sent to CZ later. My worry is that if it is the spring, and it keeps doing it , the scratch will deepen and may damage the frame permanently. James: I work on the aircraft industry and we use all sorts of the same T6 aluminum and aluminum alloys DO get corrosion. Only pure aluminum dont get corrosion and nothing that is structural is made of pure aluminum. We treat this corrosion constantly so there is a misconception that aluminum alloys dont get corrosion just because the pure aluminum dont. All aircraft alluminum sheet metal and parts (alclad) are covered by a fine pure aluminum coating but when the metal get scratches deeper that this very fine layer , your aluminum alloy will get corrosion. Aluminum corrosion is not black like iron oxyde but a fine white powder that just eats away and you end up with a nasty hole. Thats why we have to use alumiprep, zinchromate and a good paint even on brand new alclad sheets and parts. Thats also why CZ puts a parkerizing coat before the polycoat. If you see your CZ frame in the forward area that they dont polycoat you will see the parkerizing coat that looks shiny gray. That is a coating and if it gets scratched , with time, humidity, internal stresses and dissimilar metal contact it will start to corrode just like in aircraft and you will see a fine white powder forming that when removed will shown a layer taken away. The CZ warranty guy tried to sell me the same -aluminum dont get corrosion hype in the phone but I know better as I work with aluminum alloys everyday. Since an alloy have a mix of metals in it, the potential for dissimilar metal corrosion from within due to metal stress and changes in temperature do exist.If you have a part that is scratching in any way, your protective coating is gone and this corrosion will start.
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You can google it but here is some more info:
"Aluminium alloy surfaces will formulate a white, protective layer of corrosion aluminium oxide if left unprotected by anodizing and/or correct painting procedures. In a wet environment, galvanic corrosion can occur when an aluminium alloy is placed in electrical contact with other metals with more negative corrosion potentials than aluminium, and an electrolyte is present that allows ion exchange. Referred to as dissimilar metal corrosion this process can occur as exfoliation or intergranular corrosion. Aluminium alloys can be improperly heat treated. This causes internal element separation and the metal corrodes from the inside out. Aircraft mechanics deal daily with aluminium alloy corrosion."