Lesson 10: Corrosion/ Alloys Flashcards
What is corrosion?
- Corrosion is the destruction of materials by chemical reactions with substances in the environment.
What two substances are necessary to be present for iron to rust?
1.) Air.
2.) Water.
Give 1 example of corosion.
Rusting.
How can corrosion be prevented?
- Apply a coating that acts as a barrier (so that air/ water cannot be exposed to the material.)
Give 3 examples of barriers that could be used to prevent corrosion.
1.) Greasing.
2.) Painting
3.) Electropainting
What does aluminium have which protects it from further corosion?
- Has an oxide coating.
- Protects the metal from any further corosion.
What is sacrificial protection (to avoid the corosion of a material?)
- When material (that you don’t want corroded) is coated in a more reactive metal than itself.
Give an example of a sacrificial method (more reactive metal coating to protect metal material.)
- Zinc is used to galvanise iron.
True or False
Most metals in everday use are pure metals.
- False.
- Most metals in everyday use are alloys.
Fill in gaps
Bronze is an alloy of …….. and ………
- Copper
- Tin.
Fill in gaps
Brass is an alloy of ……. and …….
- Copper
- Zinc
What type of gold is usually an alloy?
- Gold used in jewelerry is usually an alloy.
Fill in gaps
Gold, used as jewelery, is usually an alloy with …….., ……… and ………..
- Silver
- Copper
- Zinc
What is the percentage of gold (in alloys of gold jewelery) measured in?
- Percentage of gold (in an alloy of gold) is measured in carats.
What does 24 carat and 18 carat gold actually mean?
In terms of how much ACTUAL gold is within these types of jewelery
- 24 carat (100% gold) = (pure gold)
- 18 carat (75% gold.)
