Cleaning and Corrosion Control Flashcards
A primary reason why ordinary or otherwise non-approved 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 which of the following reasons would a water break test be conducted?
To make certain that a bare metal surface us thoroughly clean
Select the solvent recommended for wipedown 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
Which of the following are acceptable to use when utilizing chemical cleaning agents on aircraft?
Cotton fiber wiping cloths when using a flammable agent and atomizing spray equipment
Select the solvent used to clean acrylics and rubber
Aliphatic naptha
Fayed surfaces can 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
What is another name for ‘False Brinelling’?
Fretting corrosion
The rust or corrosion that occurs with most metals is the result of
a tendency for them to return to their natural state
Which of the following are the desired effects of using Alodine on aluminum alloy?
A slightly rough surface and increased corrosion resistance
Which of the listed condition 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 build up is called
exfoliation
A non-electrolytic chemical treatment for aluminum alloys is to increase corrosion resistance and paint bonding qualities is called
alodizing
Which of the following are acceptable to use in cleaning anodized surfaces?
Aluminum wool and fiber bristle brushes
Intergranular corrosion in aluminum alloy parts
can not be detected by surface indications
Which of the following 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 intergranular 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 cylinder on engines prepared for storage?
The seal of corrosion preventative mixture will be broken
Which of the following is an acceptable first step procedure to help prevent scratching when cleaning a transparent plastic surface?
Flush the surface with clean water
Why is a plastic surface flushed with fresh water before it is cleaned with soap and water?
To prevent scratching
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
Galvanic corrosion at the interface of a dissimilar metal part may best be prevented by
placing a nonporous dielectric material between the surfaces
Corrosion caused by galvanic action is the result of
contact between two unlike metals
Of the following, 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
Which of these materials is the most anodic?
Magnesium
The interior surface of sealed structural steel tubing would be best protected against corrosion by which of the following
A coating of linseed oil
Which of these materials is the most cathodic?
Stainless Steel
Of the following, 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 stress (via shot peening) on the metal surface
- In the Galvanic or Electro-Chemical Series for metals, the most anodic metals are those will give up electrons easily
Only No.2 is true
Spilled mercury on aluminum
causes rapid and severe corrosion that is very difficult to control
