Corrosion

Question 1

What are washers used for and what material are they usually made of?

Answer 1

Used to prevent corrosion; sacrificial

Zinc

Question 2

Does carbon fiber corrode?

Answer 2

No. Carbon fiber does not corrode but it causes corrosion to the metal around it

Question 3

Worm-like corrosion

Answer 3

Filaform

Question 4

When magnesium corrodes it is most often ____ corrosion

Answer 4

Pitting

Question 5

_____ corrosion happens at joints and welded surfaces.

Answer 5

Crevice

Question 6

Which corrosion can’t be seen?

Answer 6

Intragranular

Don’t always see corrosion but still stress corrosion

Question 7

Occurs when the metals rub against one another

Answer 7

Fretting corrosion

Question 8

Reason components have lifespan

Answer 8

Fatigue corrosion

Question 9

Overtime all metal will succumb to _____ corrosion.

Answer 9

fatigue corrosion

Question 10

Where to find corrosion limits?

Answer 10

Can be found in the AMM SRM sedition, if not in SRM then AC 43.13

Question 11

What can you use when measuring corrosion?

Answer 11

Depth gauge

Question 12

If corrosion is beyond limits you can _____

Answer 12

patch

Question 13

Common Types of Primer

Answer 13

Zinc chromate

Epoxy primer

Wash primer

Question 14

Yellow / green primer

Answer 14

Zinc chromate

Question 15

Primer that can be used on all surfaces and most often used in general aviation?

Answer 15

Epoxy primer

Question 16

Magnesium requires

Answer 16

special procedures.

Question 17

treatment that looks like a gold hue

Answer 17

Aladine

Question 18

Treatment that almost looks like a paint

Answer 18

Anodize

Question 19

Protective coating used after rust removal

Answer 19

Treatment (Aladine or Anodized)

Question 20

no beading

Answer 20

Water break test

Question 21

Corrosion that on aluminum and magnesium corrosion is a white powder

Answer 21

Uniform surface corrosion

Question 22

Takes place at the boundary layer of metal alloy and originates from improper heat treatment

Answer 22

Intragranular corrosion

Question 23

Advanced form of intragranular corrosion

Answer 23

Exfoliation corrosion

Question 24

Layers of metal alloy start to separate (characterised by)

Answer 24

Exfoliation corrosion

Question 25

Characterised by black deposit around components

Answer 25

Fretting corrosion

Question 26

Deposits streak across aircraft overtime

Answer 26

Fretting corrosion

Question 27

Pushes up at the surface

Answer 27

Exfoliation corrosion

Question 28

Magnesium pitting expands and _____ paint, volume is larger than missing volume

Answer 28

Bubbles

Question 29

Very destructive, most likely to give us problems as A&P mechanics

Answer 29

Pitting Corrosion

Question 30

Starts off as uniform corrosion and if left untreated ____ develop

Answer 30

Pits

Question 31

Can pitting corrosion happen under paint?

Answer 31

Yes

Question 32

Only occurs under protective coatings

Answer 32

Filaform Corrosion

Question 33

Most common on Aluminum and Magnesium

Answer 33

Pitting Corrosion

Question 34

Oxygen, water, dirt, grease trapped in between coatings cause

Answer 34

Filaform Corrosion

Question 35

Fretting corrosion is most commonly found at _____

Answer 35

Rivets

Question 36

Can happen to welded areas

Answer 36

Stress corrosion / Stress cracking

Question 37

Larger the difference in Anode & Cathode corrosion resistance characteristics the _____ the corrosion

Answer 37

Faster

Question 38

Electrochemical - Electrochemical attack type corrosions

Answer 38

Basically verything besides chemical

Question 39

11 factors that affect corrosion

Answer 39

1. Type of metal 2. Heat-treatment and grain direction 3. Presence of a dissimilar, less corrodible metal 4. Anodic and cathodic surface areas (in galvanic corrosion) 5. Temperature 6. Presence of electrolytes (hard water, salt water, battery fluids, etc.) 7. Availability of oxygen 8. Presence of biological organisms 9. Mechanical stress on the corroding metal 10. Time of exposure to a corrosive environment 11. Lead/graphite pencil marks on aircraft surface metal

Question 40

Heat expedites corrosion, but not ____ heat.

Answer 40

dry

Question 41

first line of defense against corrosion

Answer 41

Paint Second line of defense: Cleaning aircraft / lubricated

Question 42

Rivets warping metal

Answer 42

Stress corrosion / Stress cracking