The bare metal surface of magnesium and aluminum should be treated with which of the following?

The treatment of bare metal surfaces of magnesium and aluminum with a chemical conversion compound is essential for effective corrosion protection. Chemical conversion coatings are designed to create a protective layer on the metal surface, enhancing its corrosion resistance while also providing better adhesion for subsequent coatings, such as paints or sealants.

These conversion coatings work by chemically reacting with the metal to form a thin, durable layer that can prevent oxidation and corrosion. They are particularly effective for magnesium and aluminum, which are more susceptible to corrosion due to their high reactivity. This protective layer does not just inhibit corrosion; it also improves the bond of any additional coatings that may be applied afterward.

While painting, applying a protective coating, or using a wax sealant can offer protection, these methods often require a properly treated surface to be most effective. Without the chemical conversion treatment, the underlying metal may still corrode over time, especially in harsh environments. Thus, the chemical conversion compound is a critical first step in ensuring long-lasting protection for magnesium and aluminum surfaces in avionics applications.