Corrosion/preventative measures Flashcards

1
Q

What is corrosion

A

Reaction of metal with its surrounding, such as air and water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens when an object rusts

A

Iron+oxygen+water —> hydrated iron(III)oxide
Rusting is a redox reaction
It is called rusting when iron or steel is corroded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the methods to prevent rusting/reduce it

A

Painting
Coating with oil, grease or plastic
Plating with zinc (galvanising)
Plating with tin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does Painting reduce rusting

A

Paint prevents air and water reaching the surface of the metal, but when it chips rusting starts on the exposed part of the metal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does coating with oil, grease or plastic reduce corrosion

A

Prevents the metal being exposed to the air and water, however if the coating is damaged rusting starts on the exposed metals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is sacrificial protection

A

Involves using a metal more reactive than iron such as zinc or magnesium. The more reactive metal will corrode first , protecting the iron/steel by ‘sacrificing ‘ itself.
This method is useful when painting is difficult.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is galvanising

A

Galvanising involves dipping the metal object in molten zinc. After it has cooled and solidified the thin layer of zinc stops air/water reaching the iron/steel below and acts as a sacrificial metal so the object is protected even if the zinc layer is damaged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Disadvantage of tin plating

A

Tin is less reactive than iron, so if the tin layer is damaged the steel will act as the sacrificial metal and will rust faster than normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly