NAVAIR 01-1A-509-1, Ch. 3

Question 1

Aluminum and magnesium form corrosion products that are white oxides or what else?

Answer 1

Hydroxides

Question 2

What is the most common type of corrosion (and the one that can be most effectively treated by maintenance personnel)?

Answer 2

Electrochemical

Question 3

What is the smallest unit of an element, made up of a positively charged nucleus surrounded by a system of negatively charged electrons?

Answer 3

Atom

Question 4

There are over how many elements?

Answer 4

100

Question 5

What is a negatively charged subatomic particle called?

Answer 5

Electron

Question 6

What cannot move through metal conductors?

Answer 6

Ions

Question 7

What is a liquid (usually water) solution containing ions called?

Answer 7

Electrolyte

Question 8

Which branch of science is concerned with chemical reactions at surfaces in contact with electrolytes?

Answer 8

Electrochemistry

Question 9

How many conditions must exist before metal corrosion can occur?

Answer 9

4

Question 10

What is corroding metal called?

Answer 10

Anode

Question 11

When corrosion products form, they often precipitate onto the corroding surface as a what?

Answer 11

Powdery deposit

Question 12

Since corrosion products occupy more volume than the original metal, the paint surfaces may become blistered, flaked, chipped, or appear in which way?

Answer 12

Lumpy

Question 13

Which stage is the best time to prevent corrosion?

Answer 13

Design

Question 14

Aluminum, steel, titanium, along with which other type of metal are the most commonly used in aircraft construction?

Answer 14

Magnesium

Question 15

Most alloys are made up entirely of small crystalline regions called what?

Answer 15

Grains

Question 16

Which form of corrosion are many alloys used in aircraft construction sensitive to?

Answer 16

Stress corrosion cracking

Question 17

Which type of corrosion is probably the most common type?

Answer 17

Uniform surface

Question 18

Which type of corrosion occurs when different metals are in contact with each other and an electrolyte?

Answer 18

Galvanic

Question 19

What is a form of extremely localized attack that results in holes in the metal?

Answer 19

Pitting

Question 20

Which type of metals are most susceptible to pitting damage?

Answer 20

Stainless steels

Question 21

Which type of corrosion is an attack on the grain boundaries of the metal?

Answer 21

Intergranular

Question 22

What is an advanced form of intergranular corrosion where the surface grains of a metal are lifted up by the force of expanding corrosion products occurring at the grain boundaries?

Answer 22

Exfoliation

Question 23

Which type of corrosion occurs because the environment of the local area is very different from the larger environment?

Answer 23

Crevice

Question 24

Which type of corrosion is a form of crevice corrosion which occurs on metal surfaces having a thin (~4 mils) organic protective coating?

Answer 24

Filiform

Question 25

Filiform corrosion occurs when the relative humidity of the air is between 65- 90%, and the air temperature is between which temperatures?

Answer 25

70°- 100°F

Question 26

Which type of corrosion is the increase in the rate of attack on a metal due to the action of a corrosive fluid against the metal surface?

Answer 26

Erosion

Question 27

Which type of corrosion is the intergranular or transgranular cracking of a metal caused by the combined effects of constant tensile stress (internal or applied) and corrosion?

Answer 27

Stress

Question 28

Aluminum alloy can fail by stress corrosion cracking when subjected to a stress which is only what percent of its rated strength?

Answer 28

10%

Question 29

What is the cracking of metals known as that is caused by the combined effects of cyclic stress and corrosion?

Answer 29

Corrosion fatigue

Question 30

Which type of corrosion occurs at contact areas between materials under load subject to repeated vibration?

Answer 30

Fretting

Question 31

What are the most widely used materials for aircraft construction?

Answer 31

Aluminum and aluminum alloys

Question 32

Since pure aluminum is more corrosion resistant than most alloys, aluminum sheet stock is often covered with a thin layer of nearly pure aluminum called cladding or what else?

Answer 32

Alclad

Question 33

What is the electrochemically applied oxide coating called which is used to protect some aluminum parts?

Answer 33

Anodize

Question 34

What are the lightest structural metals used for aircraft and missile airframes?

Answer 34

Magnesium alloys

Question 35

Which type of metals are used for gears, bearings, and high strength bolts, and for mountings, racks, brackets, and hardware in avionic systems?

Answer 35

Stainless steels

Question 36

Titanium and titanium alloys find numerous uses in aircraft, engines, and missiles up to which temperature?

Answer 36

1000°F

Question 37

What is used as a coating to protect steel hardware, such as bolts, washers, and screws, and as plating on electrical connectors?

Answer 37

Cadmium

Question 38

What is used as a protective plating?

Answer 38

Chromium

Question 39

When added to stainless steel alloys, the stress corrosion resistance increases with nickel contents above what percentage?

Answer 39

10%

Question 40

Which type of alloys are generally used in avionic systems as contacts, springs, leads, connectors, printed circuit board (PCB) conductors, and wires?

Answer 40

Copper and copper based

Question 41

Which type of material is used as a plating material over copper in waveguides, miniature and micro- miniature circuits, wires, contacts, high frequency cavities, tank circuits, and RF shielding?

Answer 41

Silver

Question 42

What is used on printed circuits, semiconductors, leads, and contacts and is traditionally considered the best coating for corrosion resistance and solderability?

Answer 42

Gold

Question 43

Which brittle gold-aluminum compound is formed when bonding gold to aluminum?

Answer 43

Purple plague

Question 44

Which material has the best combination of solderability and corrosion resistance of any metallic coating?

Answer 44

Tin

Question 45

Graphite or carbon fiber composites are materials which consist of reinforcing fibers in a matrix made of organic resin, usually what?

Answer 45

Epoxy

Question 46

What in addition to conformal coatings are used to envelop an avionic component, module or assembly?

Answer 46

Encapsulants

Question 47

Which type of compounds are used to encase a part or component, such as in an electrical connector?

Answer 47

Potting

Question 48

Rubbers along with what else are used for insulation, seals, gaskets, caps, tubing, films, and coatings?

Answer 48

Elastomers

Question 49

What is present in air as a gas (water vapor) or as finely divided droplets of liquid (mist or fog)?

Answer 49

Moisture

Question 50

What formation results from condensation of moisture?

Answer 50

Electrolyte

Question 51

What percentage of the ocean is salt?

Answer 51

3.5-3.9%

Question 52

Up to how many pounds of seasalt per cubic mile of air can normal sea winds carry?

Answer 52

100

Question 53

What is a particularly active form of oxygen which is formed naturally during thunderstorms, by arcing in electrical devices, and by photochemical reactions in smog?

Answer 53

Ozone

Question 54

The two ranges of solar radiation most damaging to materials are ultraviolet (the range that causes sunburn) and which other range that makes sunlight feel warm?

Answer 54

Infrared

Question 55

Most fungus growth is inhibited by temperatures above which temperature?

Answer 55

104°F

Question 56

Which type of environments is most military equipment intended for service in?

Answer 56

Low pressure (high altitude)

Question 57

Some of the least recognized contributors to corrosion are sand, dust, and what else?

Answer 57

Volcanic ash

Question 58

In arid regions such as deserts, small sand particles are often blown as high as how many feet by the siroccos (hot, dust laden winds)?

Answer 58

10,000’

Question 59

Nonmetallic materials suffer the most damage from the hot desert climates, where air temperatures during the day may reach what?

Answer 59

124°F

Question 60

The greatest challenge to the aircraft industry is the design of equipment that is protected from corrosion and deterioration in the heat and humidity that prevails in which region?

Answer 60

Tropics

Question 61

The tropical environment is sustained by long periods of heavy rainfall, during which as many as how many inches of rain may fall?

Answer 61

100”

Question 62

Which type of attack includes the action of bacteria, fungi, or molds?

Answer 62

Microbial

Question 63

Bacteria may be either aerobic or what else?

Answer 63

Anaerobic

Question 64

Which type of bacteria require oxygen to live?

Answer 64

Aerobic

Question 65

Ideal growth conditions for most fungi and bacteria are temperatures between 68° and what?

Answer 65

104°F

Question 66

What is intended to protect equipment or components against corrosion, deterioration, and physical damage during transportation and storage?

Answer 66

Packaging

Question 67

Equipment should be properly packaged in accordance with which standard to minimize damage during shipment?

Answer 67

MIL-STD-2073-1

Question 68

How many hours per day in flight operations do most front-line combat aircraft average?

Answer 68

1-2