Cleaning and Corrosion Control

Question 1

A primary reason why ordinary or otherwise non-approved compounds should not be used when washing aircraft is because their use can result in

Answer 1

hydrogen embrittlement in metal structures

Question 2

How may magnesium engine parts be cleaned?

Answer 2

Wash with a commercial solvent, decarbonize and scrape or grit blast

Question 3

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

Answer 3

chemical surface treatment

Question 4

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

Answer 4

To make certain that a bare metal surface us thoroughly clean

Question 5

Select the solvent recommended for wipedown of cleaned surfaces just before painting

Answer 5

Aliphatic naptha

Question 6

Nickel-cadmium battery cases and drain surfaces which have been affected by electrolyte should be neutralized with a solution of

Answer 6

boric acid

Question 7

Which of the following are acceptable to use when utilizing chemical cleaning agents on aircraft?

Answer 7

Cotton fiber wiping cloths when using a flammable agent and atomizing spray equipment

Question 8

Select the solvent used to clean acrylics and rubber

Answer 8

Aliphatic naptha

Question 9

Fayed surfaces can cause concern in chemical cleaning because of the danger of

Answer 9

entrapping corrosive materials

Question 10

Caustic cleaning products used on aluminum structures have the effect of producing

Answer 10

corrosion

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

What is another name for ‘False Brinelling’?

Answer 12

Fretting corrosion

Question 13

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

Answer 13

a tendency for them to return to their natural state

Question 14

Which of the following are the desired effects of using Alodine on aluminum alloy?

Answer 14

A slightly rough surface and increased corrosion resistance

Question 15

Which of the listed condition is NOT one of the requirements for corrosion to occur?

Answer 15

The presence of a passive oxide film

Question 16

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

Answer 16

exfoliation

Question 17

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

Answer 17

alodizing

Question 18

Which of the following are acceptable to use in cleaning anodized surfaces?

Answer 18

Aluminum wool and fiber bristle brushes

Question 19

Intergranular corrosion in aluminum alloy parts

Answer 19

can not be detected by surface indications

Question 20

Which of the following may not be detectable even by careful visual inspection of the surface of aluminum alloy parts or structures?

Answer 20

Intergranular corrosion

Question 21

What may be used to remove corrosion from highly stressed steel surfaces?

Answer 21

Fine-grit aluminum oxide

Question 22

A primary cause of intergranular corrosion is

Answer 22

improper heat treatment

Question 23

Corrosion should be removed from magnesium parts with a

Answer 23

stiff, nonmetallic brush

Question 24

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?

Answer 24

The seal of corrosion preventative mixture will be broken

Question 25

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

Answer 25

Flush the surface with clean water

Question 26

Why is a plastic surface flushed with fresh water before it is cleaned with soap and water?

Answer 26

To prevent scratching

Question 27

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

Answer 27

Wipe the tire with a dry cloth followed by a wash down and rinse with soap and water

Question 28

Galvanic corrosion is likely to be most rapid and severe when

Answer 28

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

Question 29

Galvanic corrosion at the interface of a dissimilar metal part may best be prevented by

Answer 29

placing a nonporous dielectric material between the surfaces

Question 30

Corrosion caused by galvanic action is the result of

Answer 30

contact between two unlike metals

Question 31

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

Answer 31

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

Question 32

Which of these materials is the most anodic?

Answer 32

Magnesium

Question 33

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

Answer 33

A coating of linseed oil

Question 34

Which of these materials is the most cathodic?

Answer 34

Stainless Steel

Question 35

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

Answer 35

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

Question 36

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

Answer 36

creating compressive stress (via shot peening) on the metal surface

Question 37

2. In the Galvanic or Electro-Chemical Series for metals, the most anodic metals are those will give up electrons easily

Answer 37

Only No.2 is true

Question 38

Spilled mercury on aluminum

Answer 38

causes rapid and severe corrosion that is very difficult to control