General A&P Practice Test

Alodine is a chromate conversion coating applied to aluminum that creates a thin, protective film on the surface. This film passivates the metal and serves as a barrier to moisture and oxygen, which significantly improves corrosion resistance while keeping the surface electrically conductive. It’s not a process that makes the surface rough, and it doesn’t remove all oxides or render conductivity zero; the coating is thin enough to allow electrical conduction to continue, just with enhanced protection. So the statement that it increases corrosion resistance best captures the coating’s purpose and effect.