Cleaning and Corrosion Control

Define metal corrosion.

• Deterioration of metal by chemical or electrochemical attack that can occur internally & externally.

• Changes smooth surface.

• weakens interior, damages and/or loosens adjacent parts.

• All are correct.

What form of corrosion is exfoliation and how is its appearance described?

• Very severe Causing lifting or flaking or metal surface due to delamination of grain boundaries.

• Delamination of grain boundaries is caused by corrosion forcing material to move away from body.

• Both are correct.

Explain the corrosion process.

• Metal that is oxidized (loss of electron) suffers anodic change.

• Corrosive agent reduced (gain of electron) undergoes cathodic change.

• Both are correct.

What is ferrous oxide?

• Rust.

• Common type of surface corrosion.

• Result of atmospheric oxidation on the surface of steel.

• All are correct choices.

Define stress corrosion.

• Sustained tensile stresses.

• A corrosive environment.

• Both choices are correct.

Define fretting corrosion.

• Two mating surfaces, normally at rest with respect to one another, are subject to slight relative motion.

• Common result of changes that can occur during manufacturer's heating and cooling process. Attacks along grain of an alloy.

Define intergranular corrosion.

• Common result of changes that can occur during manufacturer's heating and cooling process. Attacks along grain of an alloy.

• Two mating surfaces, normally at rest with respect to one another, are subject to slight relative motion.

When would you polish an aircraft and what are the benefits?

• When use of liquids is not desirable or practical. Removes airport film, dust, and small accumulations of dirt and soil.

• Usually performed after surfaces have been cleaned. Restores luster to surfaces and removes oxidation and corrosion.

When would a dry wash be accomplished and what does it remove?

• Usually performed after surfaces have been cleaned. Restores luster to surfaces and removes oxidation and corrosion.

• When use of liquids is not desirable or practical. Removes airport film, dust, and small accumulations of dirt and soil.

What does wet washing NOT remove?

• Corrosion.

• Oxide films.

• Both are correct choices.