Navair 01-1A-509-1

Front 1

What are the two most important factors in preventing corrosion?

Back 1

1. Removal of the electrolyte

2. Application of protective coating

Front 2

What is the electrochemical deterioration of a material or its properties due to its chemical reaction with the surrounding environment?

Back 2

Corrosion

Front 3

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

Back 3

Atom

Front 4

What is a negatively charged subatomic particle?

Back 4

Electron

Front 5

What is an atom or group of atoms or molecules which has acquired a net electric charge by gaining or losing electrons?

Back 5

Ion

Front 6

What is a liquid containing ions?

Back 6

Electrolyte

Front 7

All metals will corrode to some extent in a natural environment.

Back 7

Theory of Corrosion

Front 8

What four conditions must exist before metal corrosion can occur?

Back 8

1. Anode (metal with tendency to corrode)

2. Cathode (dissimilar conductive material)

3. Electrolyte (conductive liquid)

4. Electrical contact

Front 9

Where do all corrosive attacks begin?

Back 9

On the surface of the metal

Front 10

When is the best time to prevent corrosion?

Back 10

Design stage

Front 11

Most alloys are made up entirely of small crystalline regions called _____.

Back 11

Grains

Front 12

The _____ the difference in dissimilar metals, the _____ corrosion occurs.

Back 12

Greater, difference

Front 13

If the surface area of the _____ (corroding metal) is smaller than the surface area of the _____ (less active metal), corrosion will be rapid and severe.

Back 13

Anode, cathode

Front 14

What occurs when the concentration of the electrolyte on the surface varies from one location to another?

Back 14

Concentration Cell

Front 15

What occurs when some of the electrolyte on a metal surface is partially confined, metal in the confined area corrodes more rapidly than other metal surface areas?

Back 15

Oxygen Concentration Cell

Front 16

What environments tend to produce more rapid corrosion due to accelerated chemical reactions?

Back 16

Higher temperature

Front 17

What is the most common type of corrosion that results from a direct chemical attack on a metal surface that proceeds over the entire exposed surface?

Back 17

Uniform Surface Corrosion

Front 18

What two appearances does uniform surface corrosion have?

Back 18

1. Dulling or etching of surface.

2. Rough and possibly frosted.

Front 19

What two ways can you treat uniform surface corrosion?

Back 19

1. Coating/sealing

2. Air movement and drain holes

Front 20

What corrosion occurs when different metals are in contact with each other and an electrolyte, such as seat water?

Back 20

Galvanic Corrosion

Front 21

What appearance does galvanic corrosion have?

Back 21

Corrosion at the joint between metals

Front 22

When is the potential for galvanic corrosion the greatest?

Back 22

When two metals are well separated from each other on the galvanic series.

Front 23

What corrosion occurs when the form of extremely localized attacks results in holes in the metal?

Back 23

Pitting Corrosion

Front 24

What appearance does pitting corrosion have?

Back 24

White or gray powdery deposits, similar to dust.

Front 25

What metal is most susceptible to pitting?

Back 25

Stainless steel

Front 26

What corrosion is the attack on the grain boundaries of the metal?

Back 26

Intergranular Corrosion

Front 27

What type of corrosion are aluminum alloys highly susceptible to?

Back 27

Intergranular Corrosion

Front 28

What is the 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?

Back 28

Exfoliation Corrosion

Front 29

What appearance does exfoliation corrosion have?

Back 29

Lifting up or swelling

Front 30

How do you prevent exfoliation corrosion in aluminum sheet around steel fasteners?

Back 30

Separate the aluminum and steel by a barrier

Front 31

What corrosion occurs when in any crevice where a stagnant solution has pooled?

Back 31

Crevice Corrosion

Front 32

What three methods are used to close crevices in order to prevent crevice corrosion?

Back 32

1. Welding

2. Soldering

3. Nonabsorbent gaskets

Front 33

What is a form of crevice corrosion which occurs on metal surfaces having a thin organic protective coating?

Back 33

Filiform Corrosion

Front 34

What corrosion is recognized by its characteristic worm-like trace of corrosion products beneath the coating?

Back 34

Filiform Corrosion

Front 35

What four ways can filiform corrosion be prevented?

Back 35

1. Keep humidity below 65%

2. Using coating with low rate of diffusion of oxygen and water vapors

3. Maintaining coatings

4. Applying CPC (corrosion preventive compounds)

Front 36

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

Back 36

Erosion Corrosion

Front 37

What is erosion corrosion characterized by?

Back 37

Grooves, gullies, waves, rounded holes and/or valleys in the metal surface

Front 38

What is the intergranular or transgranular cracking of a metal caused by the combined effects of constant tensile stress and corrosion?

Back 38

Stress Corrosion (also called Stress Corrosion Cracking SCC)

Front 39

What type of corrosion is an extremely dangerous type of failure because it can occur without warning?

Back 39

Stress Corrosion (also called Stress Corrosion Cracking SCC)

Front 40

What three specific environmental effects have been identified which cause stress corrosion cracking?

Back 40

1. Salt solutions

2. Sea water

3. Moist salt laden air

Front 41

What three ways can stress corrosion be prevented?

Back 41

1. Insulating barrier

2. Protective coatings

3. Water dispalcing corrosion preventive compunds

Front 42

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

Back 42

Corrosion Fatigue

Front 43

What three measures are used to prevent corrosion fatigue?

Back 43

1. Reduce stress

2. Use corrosion inhibitors

3. Apply metallic coating

Front 44

What corrosion occurs at the contact areas between materials under load subject to repeated vibration?

Back 44

Fretting Corrosion

Front 45

What general appearance does fretting corrosion have?

Back 45

Galling

Front 46

What corrosion occurs at high temperatures, such as those found in turbine engine combustors, turbine sections, and afterburners?

Back 46

Hot Corrosion

Front 47

What can reduce hot corrosion?

Back 47

High temperature ceramic coatings

Front 48

What are the most widely used materials for aircraft construction?

Back 48

Aluminum and aluminum alloys

Front 49

What is the corrosion product of aluminum?

Back 49

White to gray powdery material

Front 50

What two ways can corrosion of aluminum be removed?

Back 50

1. Mechanical polishing

2. Abrasive brushing

Front 51

What are the three main methods of protection of aluminum?

Back 51

1. Chemical coating

2. Paints

3. CPC (corrosion preventive compounds)

Front 52

What is an electrochemically applied oxide coating used for protecting of metals?

Back 52

Anodize

Front 53

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

Back 53

Magnesium alloys

Front 54

What are the corrosion products of magnesium alloys?

Back 54

White powdery snow-like mounds

Front 55

How can the corrosion of magnesium alloys be diminished?

Back 55

Use of proper protective finish

Front 56

What six types of corrosion is aluminum alloy susceptible to?

Back 56

1. Pitting

2. Intergranular

3. Exfoliation

4. Stress

5. Fatigue

6. Fretting

Front 57

What is the corrosion appearance of aluminum alloy?

Back 57

White to gray powder

Front 58

What type of corrosion is magnesium alloy susceptible to?

Back 58

Pitting

Front 59

What are three corrosion appearances of magnesium alloy?

Back 59

1. White powdery

2. Snow-like mounds

3. White spots

Front 60

What two types of corrosion is carbon and low alloy steel susceptible to?

Back 60

1. Pitting

2. Intergranular

Front 61

What is the corrosion appearance of carbon and low alloy steel?

Back 61

Reddish-brown oxide (rust)

Front 62

What five types of corrosion is stainless steels susceptible to?

Back 62

1. Crevice corrosion

2. Pitting

3. Stress

4. Intergranular

5. Uniform surface

Front 63

What is the corrosion appearance of stainless steels?

Back 63

Rough surface

Front 64

What type of corrosion is titanium alloy susceptible to?

Back 64

Highly corrosive resitant

Front 65

What is the corrosion appearance of titanium alloy?

Back 65

Colored surface oxides develop above 700 F.

Front 66

What type of corrosion is cadmium susceptible to?

Back 66

Uniform Surface Corrosion

Front 67

What are the two corrosion appearances of cadmium?

Back 67

1. White powdery deposit

2. Black/brown molting of surface

Front 68

What type of corrosion is chromium susceptible to?

Back 68

Pitting

Front 69

What type of corrosion is nickel-base alloy susceptible to?

Back 69

Pitting

Front 70

What is the corrosion appearance of nickel-base alloy?

Back 70

Green powdery deposit

Front 71

What two types of corrosion is electroless nickel susceptible to?

Back 71

1. Pitting

2. Uniform surface

Front 72

What two types of corrosion is copper-base alloy, brass, and bronze susceptible to?

Back 72

1. Surface

2. Intergranular

Front 73

What are the two corrosion appearances of copper-base alloy, brass, and bronze?

Back 73

1. Blue powdery deposit

2. Green powdery deposit

Front 74

What type of corrosion is silver susceptible to?

Back 74

Will tarnish in the presence of sulfur

Front 75

What is the corrosion appearance in silver?

Back 75

Brown to black film

Front 76

T/F. Gold is highly corrosion resistant.

Back 76

True

Front 77

What is the corrosion appearance in gold?

Back 77

Deposits cause darkening of reflective surfaces

Front 78

What is the corrosion appearance in tin?

Back 78

Whisker-like deposits

Front 79

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

Back 79

Cadmium

Front 80

What is used as a protective plating?

Back 80

Chromium