Which statement about Alodine coating is accurate?

Which statement about Alodine coating is accurate?

• A. It makes surface too rough
• B. It eliminates all surface oxides
• C. It reduces electrical conductivity to zero
• D. It increases corrosion resistance

Answer: (D)

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.

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.