ChatGPT :
When corrosion marks are visible on an F-35, which coating is affected?
In general, if corrosion is visible on an F-35, it means that several protective layers have already been compromised, including:
1. Final layer: Stealth coating / RAM
This is the first layer to be exposed to the environment (rain, sand, salt, UV rays). It can degrade or crack over time, due to maneuvers or wear and tear. If it is damaged, it allows moisture to pass through to the inner layers.

2. Anti-corrosion primer
Just below the RAM coating. If the stealth coating is damaged but the primer is intact, corrosion does not develop immediately. But if the primer is also damaged (or was poorly applied in the first place), then the metal surfaces begin to corrode.

3. Structural materials (aluminum, titanium, etc.)
These are the basic materials used in aircraft construction. Some components of the F-35 are still made of aluminum alloy, which is more susceptible to corrosion, especially in saline environments (e.g., marine).

What this means:
If visible corrosion is seen on agptn F-35, it means that the stealth coating and anti-corrosion primer are damaged, exposing the internal metal structure to the environment.

Why this is a big problem on an F-35:
Exposure to corrosion impairs stealth (uneven surface, altered radar reflectivity). This reduces the longevity of components. Repair is time-consuming, costly, and delicate (the stealth coating must be reapplied perfectly).