Cleaning and Corrosion Control Flashcards
A primary reason why ordinary or other non-approved cleaning compounds should not be used when washing aircraft is because their use can result in…
Hydrogen embrittlement in metal structures.
How may magnesium engine parts be cleaned?
Wash with a commercial solvent, decarbonize, and scrape or grit blast.
When an anodized surface coating is damaged in service, it can be partially restored by…
Chemical surface treatment.
For what reason would a water break test be conducted?
To make certain that a bare metal surface is throughly clean.
What is the solvent recommended for wipe down of cleaned surfaces just before painting?
Aliphatic naptha.
Nickel-cadmium battery cases and drain surfaces which have been affected by electrolyte should be neutralized with a solution of…
Boric acid.
What is acceptable to use when utilizing chemical cleaning agents on aircraft?
Cotton fiber wiping cloths when using a flammable agent and atomizing spray equipment.
Solvent used to clean acrylics and rubber.
Aliphatic naphtha.
Fayed surfaces cause concern in chemical cleaning because of the danger of…
Entrapping corrosive materials.
Caustic cleaning products used on aluminum structures have the effect of producing…
Corrosion.
Fretting corrosion is most likely to occur…
When two surfaces fit tightly together but can move relative to one another.
The rust or corrosion that occurs with most metals is the result of…
A tendency for them to return to their natural state.
What is the desired effects of using Aldine on aluminum alloy?
A slightly rough surface and increased corrosion resistance.
What is NOT one of the requirements for corrosion to occur?
The presence of a passive oxide film.
The lifting or flaking of the metal at the surface due to delamination of grain boundaries caused by the pressure of corrosion residual product buildup is called…
Exfoliation.
A non-electrolytic chemical treatment for aluminum alloys to increase corrosion resistance and paint-bonding qualities is called…
Alodizing.
What is acceptable to use in cleaning anodized surfaces?
Aluminum wool and fiber bristle brushes.
Intergranular corrosion in aluminum alloy parts…
Cannot always be detected by surface indications.
What may not be detectable even by careful visual inspection of the surface of aluminum alloy parts or structures.
Intergranular corrosion.
What may be used to remove corrosion from highly stressed steel surfaces?
Fine-grit aluminum oxide.
A primary cause of inter- granular corrosion is…
Improper heat treatment.
Corrosion should be removed from magnesium parts with a…
Stiff, nonmetallic brush.
Why is it important not to rotate the crankshaft after the corrosion preventive mixture has been put into the cylinders on engines prepared for storage?
The seal of corrosion preventative mixture will be broken.
What is an acceptable first step procedure to help prevent scratching when cleaning a transparent plastic surface?
Flush the surface with clean water.
What should be done to prevent rapid deterioration when oil or grease come in contact with a tire?
Wipe the tire with a dry cloth followed by a wash down and rinse with soap and water.
Galvanic corrosion is likely to be most rapid and severe when…
The surface area of the anodic metal is smaller than the surface area of the cathodic metal.
Corrosion cause by galvanic action is the result of…
Contact between two unlike metals.
What material is the most anodic?
Magnesium.
The interior surface of sealed structural steel tubing would be best protected against corrosion by what?
A coating of linseed oil.
Which of these materials is the most cathodic? (Zinc, Stainless steel, or 2024 aluminum alloy)
Stainless steel.
When and/or where is galvanic corrosion most likely to occur?
At the interface of a steel fastener and aluminum alloy inspection plate in the presence of an electrolyte.
One way of obtaining increased resistance to stress corrosion cracking is by…
Creating compressive stresses (via shot peening) on the metal surface.
Spilled mercury on aluminum…
Causes rapid and severe corrosion that is very difficult to control.
