Corrosion

Question 1

Intergrannular corrosion is often caused by

Answer 1

Improper heat treatment

Question 2

Corrosion caused by electrolytic action is the result of

Answer 2

Contact between two unlike metals

Question 3

Corrosion may be regarded as the destruction of metal by

Answer 3

Electrochemical action

Question 4

Exfoliation corrosion could be referred to as

Answer 4

Layer corrosion

Question 5

When dissimilar metals are brought together, or the same metal in different states, one metal forms the anode and the other the cathode. Which will suffer the corrosion?

Answer 5

The anode

Question 6

In corrosion, the electrode that loses electrons is

Answer 6

Either the cathode or the anode depending upon the electrolyte

Question 7

What is a common, ongoing cause of corrosion?

Answer 7

Spilled battery acid

Question 8

What is stress corrosion?

Answer 8

Corrosion in an area under continuous loading

Question 9

Electrochemical reaction is caused by the contact of

Answer 9

Moisture on the surface of an inert metal

Question 10

Chemical attack is a direct result of

Answer 10

Cathodic and anodic changes in the material

Question 11

Galvanic corrosion is caused by

Answer 11

The joining of 2 dissimilar metals

Question 12

With reference to the galvanic series, the most noble of two metals in contact, will

Answer 12

Cause the less noble metal to corrode

Question 13

Stress corrosion is associated with

Answer 13

A corrosion put in a member under stress

Question 14

Corrosion will spread more rapidly when metals are exposed to

Answer 14

High temperatures

Question 15

What is correct regarding chemical testing?

Answer 15

The chemical test for bronze is nitric acid which produces a white precipitate

Question 16

All corrosion is a chemical reaction. True or false?

Answer 16

True

Question 17

In a poorly produced repair to skin structure, where would stress corrosion start?

Answer 17

Radiate from the corner or sharp edges

Question 18

Some metals are inherently stable. What does this suggest?

Answer 18

They strongly resist corrosion

Question 19

The oxide film formed on the surface of the aluminium is

Answer 19

Non-porous

Question 20

Corrosion control begins at the

Answer 20

Design stage

Question 21

Aluminium is

Answer 21

Highly resistant to corrosion

Question 22

When galvanic corrosion takes place, which part corrodes?

Answer 22

Anode

Question 23

Corrosion caused by galvanic action is the result of

Answer 23

Contact between two unlike metals

Question 24

What are the signs of fretting corrosion?

Answer 24

Black powder or cocoa staining

Question 25

Black streaks from a rivet hole signify

Answer 25

Fretting

Question 26

When a steel part is welded, corrosion occurs because

Answer 26

The strip has become anodic

Question 27

Intergranular corrosion

Answer 27

May have no visual surface indication

Question 28

Jointing compound is used for what reason?

Answer 28

To prevent dissimilar metal corrosion

Question 29

The lifting of flaking of the metal at the surface due to delamination of grain boundaries caused by the pressure of corrosion is

Answer 29

Electrolysis

Question 30

The electrolytic process that forms an oxide film on the surface of the surface of aluminium alloys is known as

Answer 30

Anodising

Question 31

What is the indication of fretting corrosion on aluminium alloy

Answer 31

Black powder

Question 32

What action is taken to protect integral tanks from corrosion due to microbiological growth?

Answer 32

A biocidal additive is used in the fuel

Question 33

What type of corrosion attacks grain boundaries of aluminium alloys which are improperly or inadequately heat treated?

Answer 33

Intergranular corrosion

Question 34

One of the processes which artificially produces a film of oxide on the surface of aluminium or its alloys is commonly called

Answer 34

Anodising

Question 35

Intergranular corrosion in structural aluminium alloy parts

Answer 35

May be detected by the white, powdery deposit formed on the surface of the metal OR Cannot always be detecting by surface indications

Question 36

Corrosion will spread more rapidly when metals are exposed to

Answer 36

High temperatures

Question 37

Magnesium alloy components are protected by

Answer 37

A chemical process

Question 38

Corrosion at the grain boundaries is called

Answer 38

Intergranular

Question 39

Fretting corrosion occurs where

Answer 39

Two material are subject to very slight movement between the two

Question 40

Spilled Mercury on aluminium

Answer 40

Reduces the corrosion resistance after time in contact OR Causes rapid and severe corrosion in short time period

Question 41

The usual manufacturers anti-corrosion process to be applied to Fe aircraft parts is

Answer 41

Cadmium plating

Question 42

To check the interior of tubular members for corrosion attack

Answer 42

Ultra sonic testing or x-ray is necessary

Question 43

The form of corrosion most likely to cause stress concentration is

Answer 43

Pitting corrosion

Question 44

Lead acid battery fluid has been found to be leaking on the surface of the aircraft structure. What substance would you use to neutralise the acid?

Answer 44

Sodium bicarbonate of soda

Question 45

What colour is the corrosion found on the surface of aluminium alloys?

Answer 45

White/Grey

Question 46

Corrosion on copper is identified by

Answer 46

Green discolouration

Question 47

When examining a piece of metal through a magnifying glass, hair line cracks would indicate

Answer 47

Intergranular corrosion

Question 48

Corrosion is always completely removed

Answer 48

To permit the extent of damage to be assessed

Question 49

What is a temporary protective measure?

Answer 49

Chromating

Question 50

Spilled Mercury on aluminium causes

Answer 50

Greyish powder, fuzzy deposit or whiskery growth

Question 51

What are acceptable to use in cleaning anodised surfaces?

Answer 51

Aluminium wool, fibre bristle brush

Question 52

Which of these materials is the most anodic; magnesium, cadmium or 7075-T6 aluminium alloy

Answer 52

Magnesium

Question 53

Which of these materials is the most cathodic; 2024 aluminium alloy, zinc or stainless steel

Answer 53

Stainless steel

Question 54

Galvanic corrosion is most likely to be most rapid and severe when

Answer 54

The area of the anode is smaller an the area of the cathode OR The area of the cathode and the anode are similar

Question 55

What is the most cathodic; nickel, magnesium or stainless steel?

Answer 55

Stainless steel