Corrosion and its prevention: including half equations
I can describe corrosion in detail, including chemical equations, and describe what actions can be taken to prevent corrosion.
Corrosion and its prevention: including half equations
I can describe corrosion in detail, including chemical equations, and describe what actions can be taken to prevent corrosion.
Lesson details
Key learning points
- Corrosion is a general process of degradation of metals through various causes.
- Rusting is a specific type of corrosion, affecting iron in the presence of air and moisture.
- A metal oxide layer can protect the underlying metal if the oxide forms a physical barrier.
- Some coatings are reactive and contain a more reactive metal to provide sacrificial protection, e.g. zinc to galvanise.
- Electroplating can be used to improve the appearance and/or the resistance to corrosion of metal objects.
Common misconception
Students often believe rusting refers to the oxidation of any metal, and that corrosion is linked to the hazard 'corrosive'.
Highlight the conditions required for rusting, and the general description of corrosion.
Keywords
Rusting - The corrosion of iron or steel, in the presence of water and oxygen.
Corrosion - The gradual deterioration of a substance when it reacts with substances in the environment, for example when a metal oxidises in air.
Sacrificial protection - Using a more reactive metal to corrode preferentially, to protect another metal from corrosion.
Tarnishing - The process by which a thin, discoloured layer forms on the surface of a metal due to reactions with the environment, e.g. oxidation.
Electroplating - A process that uses electricity to deposit a thin layer of metal onto the surface of another conductive object.
Equipment
None required.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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