C20 Making our resources Flashcards
What is corrosion?
When a material reacts with substances in the environment and eventually wears away
How can corrosion be prevented?
Physical barriers e.g coated in paint or plastic
Sacrificial protection
How does aluminium have its own physical barrier?
Aluminium reacts with oxygen to produce aluminium oxide
This acts as a physical barrier to protect against corrosion
What is sacrificial protection?
A more reactive substance is placed on the material
The more reactive substance will react with the environment instead of the main material
Example of sacrificial protection
Iron is galvanised with zinc
Zinc reacts with oxygen and water in place of the iron
Composition of BRONZE
Copper and tin
Properties of BRONZE
Resistant to corrosion
Uses of BRONZE
Statues
Decorative items
Ship propellers
Composition of BRASS
Copper and zinc
Properties of BRASS
Very hard but workable
Uses of BRASS
Door fittings
Taps
Musical instruments
Composition of GOLD ALLOYS
Mostly Gold with copper, silver and zinc added
Properties of GOLD ALLOYS
Attractive
Corrosion resistant
Hardness depends on carat
Composition of HIGH CARBON STEEL
Iron with 1-2% carbon
Properties of HIGH CARBON STEEL
Strong but brittle
Uses of HIGH CARBON STEEL
Cutting tools
Metal presses
Composition of LOW CARBON STEEL
Iron with <1% carbon
Properties of LOW CARBON STEEL
Soft
Easy to shape
Uses of LOW CARBON STEEL
Cars
Machinery
Ships
Containers
Structural steel
Composition of STAINLESS STEEL
Iron with chromium and nickel
Properties of STAINLESS STEEL
Resistant to corrosion
Hard
Uses of STAINLESS STEEL
Cutlery
Plumbing
Composition of ALUMINIUM ALLOYS
Over 300 alloys available
Properties of ALUMINIUM ALLOYS
Low density
Properties depend on compostion