5.5 and 5.6 Alloys

Question 1

Iron alloys

Answer 1

Pure iron is much too soft for most purposes, so it is mixed with carbon and other metals to produce alloys called steels.

Question 2

Carbon steel

Answer 2

There are many different types of steel, with carbon steel being the most common, which consist of iron with up to 2% carbon and are harder and stronger than iron.

Question 3

Stainless steel

Answer 3

Stainless steel is an iron alloy which is resistant to corrosion. It is used to make cutlery, dishwashers and washing machine drums.

It contains chromium and has an invisible thin layer of chromium oxide which stops air and water reaching the iron and the layer reforms if scratched.

Question 4

Magnalium

Answer 4

Magnalium is an alloy of aluminium which is mixed with magnesium to make car and airplane parts.

Question 5

Jewellery gold

Answer 5

Jewellery gold is an alloy of (you guessed it) gold which is mixed with copper so it stays shiny, attractive and resistant to corrosion. It is used for (you guessed it again) jewellery.

Question 6

Brass

Answer 6

Brass is an alloy of copper and it is mixed with zinc so it is resistant to corrosion and it conducts coins. It is used for electrical plugs and coins.

Question 7

Alloys

Answer 7

Alloys work because in a pure metal, all the ions are the same size and are in a regular arrangement which means the layers slide over each other relatively easily. In an alloy, there are different sized ions of different metals, meaning that the metal can be much harder and stronger.

Question 8

Low-carbon and high-carbon steels

Answer 8

Low-carbon steels are easily shaped and are used for sheeting

High-carbon steels are hard and are used for cutting tools
Stainless steels are resistant to corrosion and are used for cutlery