Chapter 12: Cleaning and Corrosion

Question 1

a primary reason why ordinary or other wise nonapproved cleaning compounds should not be used when washing aircraft is because their use can result in

Answer 1

hydrogen embrittlement in metal

Question 2

how may magnesium engine parts be cleaned.

Answer 2

wash with a commercial solvent, decarbonize and scrape or grit blast.

Question 3

select the solvent recommended for wipe down for cleaned surfaces just before painting.

Answer 3

aliphatic naphtha

Question 4

which of the following are acceptable to use when utilizing chemical cleaning and/or de painting/stripping agents on aircraft.
1. synthetic fiber wiping cloths when using a flammable agent
2. cotton fiber wiping cloths when using a flammable agent
3. atomizing spray equipment

Answer 4

cotton fiber wiping cloths when using a flammable agent.

Question 5

select the solvent used to clean acrylics and rubber

Answer 5

Aliphatic naptha

Question 6

fayed surfaces cause concern in chemical cleaning because of the danger of

Answer 6

entrapping corrosive materials

Question 7

caustic cleaning products used on aluminum structures have the effect of producing.

Answer 7

corrosion

Question 8

which of the following is an acceptable first step procedure to help prevent scratching when cleaning transparent plastic surface?

Answer 8

flush the surface with clean water

Question 9

what should be done to prevent rapid deterioration when oil or grease come in contact with tire

Answer 9

wipe the tire with a dry cloth folowed by a wash down and rinse with soap an water

Question 10

what type of corrasion attacks gain boundaries of aluminum alloys which are improperly or inadequately heat treated

Answer 10

integranular

Question 11

fretting corrosion is most likely to occur

Answer 11

when two surfaces fit tightly together but can move relative to one another

Question 12

the rust or corrosion that occurs with most metals is the result of

Answer 12

a tendency for them to return to their natural state

Question 13

which of listed conditions is NOT one of the requirements for corrosion to occur

Answer 13

the presence of a passive oxide film

Question 14

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

Answer 14

exfoliation

Question 15

which of the following may not be detectable even by carful visual inspection of the surface of aluminum alloy parts or structures

Answer 15

intergranular corrosion

Question 16

a primary cause of intergranular corrosion is

Answer 16

improper heat treatment

Question 17

corrosion caused by galvanic action is the result of

Answer 17

contact between two unlike metals

Question 18

which of these materials is the most andoic

Answer 18

magnesium

Question 19

which of these materials is the most cathodic

Answer 19

stainless steel

Question 20

galvanic corrosion is likely to be most rapid and severe when.

Answer 20

the surface area of the anodic metal is smaller than the surface area of the cathodic metal

Question 21

One way of obtaining increased resistance to stress corrosion cracking is by

Answer 21

Creating compressive stresses (via shot peening) on the metal surface

Question 22

In the Frozen process it is the cathodic area of dissimilar cathodic material that corrodes
In the galvanic or electro chemical series for metals the most annotic metals are those that will give up electrons most easily

Answer 22

In the galvanic or electro chemical series for metals the most annotic metals are those that will give up electrons most easily

Question 23

Spilled mercury on aluminum

Answer 23

Causes rapid and severe corrosion that is very difficult control

Question 24

Of the following when and or where is galvanic corrosion most likely to occur

Answer 24

At the interface of a steel faster and aluminum alloy inspection plate in the presence of an electrolyte

Question 25

When an anodized surface coating is damaged in service, it can be partially restored by

Answer 25

Chemical surface treatment

Question 26

Which of the following are the desired effects of using alodine on aluminum alloy

Answer 26

A slightly rough surface
Increased corrosion resistance

Question 27

A non electrolytic chemical treatment for aluminum alloys to increase corrosion resistance and paint-bonding qualities is called

Answer 27

Alodizing

Question 28

Corrosion should be removed from magnesium parts with a

Answer 28

Stiff, hog-bristle brush

Question 29

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

Answer 29

The seal of corrosion preventive mixture will be broken

Question 30

The interior surface of sealed structural steel tubing would be best protected against corrosion by which of the following

Answer 30

Coating of linseed oil

Question 31

For which of the following reasons would a water break test be conducted

Answer 31

To make certain that a bare metal surface is thoroughly clean