4-50.
Corrosion may occur in several forms,
depending on which of the following
factors?
1.
Metal involved only
2.
Atmospheric conditions only
3.
Corrosion-producing agents present
only
4.
Metal involved, atmospheric
conditions, and corrosion-producing
agents present
A. Direct surface attack
B. Pitting corrosion
C. Crevice attack
D. Intergranular corrosion
E. Exfoliation corrosion
F. Fretting corrosion
G. Fatigue corrosion
H. Galvanic corrosion
I. Filiform corrosion
J. Microbiological corrosion
Figure 4-A
IN ANSWERING QUESTIONS 4-51 THROUGH
4-60, CHOOSE THE FORM OF CORROSION
FROM FIGURE 4-A THAT FITS THE
DESCRIPTION OF THE CORROSION USED AS
THE QUESTION. EACH FORM OF
CORROSION IS USED AS AN ANSWER ONLY
ONCE.
4-51.
Threadlike filaments that form under
organic substances (such as paint film).
1. A
2.
C
3.
F
4.
I
4-52.
Fungus growths on the sealing materials of
integral fuel tanks.
1. J
2.
F
3.
D
4.
B
4-53.
Slipping movement between two mating
metal surfaces.
1. C
2. E
3. F
4.
I
4-54.
Uniform etching of the metal surfaces.
1. A
2. B
3. C
4.
G
4-55. Shallow indentations or deep cavities of
small diameter that form on metal surfaces.
1.
I
2.
H
3.
E
4. B
4-56.
Caused by the difference in concentration
of the electrolyte or the active metal on the
anode and cathode.
1. A
2. C
3.
G
4.
J
4-57.
Corrosive attack along the grain boundaries
of a metal alloy.
1. C
2.
D
3.
I
4.
J
4-58.
Metal fractures caused by the combined
effects of corrosion and stress applied in
cycles to a part.
1. G
2.
F
3. E
4.
D
27
