AMT Corrosion Control and Treatment 2

Question 1

Which type of corrosion is most commonly found between mating surfaces of dissimilar metals?

Accepted Answer

Galvanic corrosion

Answer

Galvanic corrosion occurs when two dissimilar metals are in electrical contact in the presence of an electrolyte, causing the less noble metal to corrode.

Question 2

What is the primary purpose of alodine (chromate conversion coating) treatment on aluminum?

Accepted Answer

To provide corrosion protection and improve paint adhesion

Answer

Alodine (MIL-DTL-5541) creates a chemically bonded chromate layer on aluminum that resists corrosion and serves as an excellent primer bonding surface.

Question 3

Intergranular corrosion in aluminum alloys is most dangerous because it:

Accepted Answer

Attacks along grain boundaries beneath the surface with little external evidence

Answer

Intergranular corrosion progresses along grain boundaries beneath the metal surface, making it difficult to detect visually until significant structural damage has occurred.

Question 4

When removing corrosion from an aluminum aircraft structure, which abrasive should NOT be used?

Accepted Answer

Steel wool or steel wire brushes

Answer

Steel wool or steel wire brushes embed steel particles into the aluminum surface, creating galvanic corrosion sites that accelerate future corrosion.

Question 5

What does the term 'anodic' mean in the context of the galvanic series?

Accepted Answer

The metal is less noble and will corrode preferentially

Answer

Anodic metals are less noble (more active) in the galvanic series and will corrode preferentially when coupled with a more cathodic (noble) metal.

(AMT) Aviation Maintenance Technician Practice Test

(AMT) Aviation Maintenance Technician Practice Test

AMT Corrosion Control and Treatment 2