9.5.2

Preventing Corrosion

Test yourself

Preventing Corrosion

There are three main methods used to stop metals corroding.

Illustrative background for CoatingsIllustrative background for Coatings ?? "content

Coatings

  • We can prevent corrosion by applying a coating that acts as a barrier, such as greasing, painting or electroplating.
    • E.g. Aluminium has an oxide coating that protects the metal from further corrosion by preventing the metal's surface coming into contact with oxygen and water.
  • A disadvantage is that any damage to the coating will lead to the metal becoming exposed and so corrosion will take place.
Illustrative background for Sacrificial methodIllustrative background for Sacrificial method ?? "content

Sacrificial method

  • In the sacrificial method, a metal that requires protection will have a more reactive metal attached to it.
    • The metal is attached to a more reactive metal and the more reactive metal will undergo oxidation, leaving the less reactive metal intact.
  • This means that water and oxygen will stop reacting with the protected metal as they are too busy reacting with the sacrificial metal!
Illustrative background for GalvanisingIllustrative background for Galvanising ?? "content

Galvanising

  • Galvanising is a hybrid of coatings and the sacrificial method.
    • The metal that needs protecting is sprayed with a more reactive metal (e.g. zinc).
    • This initially acts as a coating.
    • If the more reactive metal is damaged, it will continue to protect as a sacrificial metal.

Jump to other topics

1States of Matter

2Atoms, Elements & Compounds

3Stoichometry

4Electrochemistry

5Chemical Energetics

6Chemical Reactions

7Acids, Bases & Salts

8The Periodic Table

9Metals

10Chemistry of the Environment

11Organic Chemistry

11.1Formulae, Functional Groups & Terminology

11.2Naming Organic Compounds

11.3Fuels

11.4Alkanes

11.5Alkenes

11.6Alcohols

11.7Carboxylic Acids

11.8Polymers

12Experimental Techniques & Chemical Analysis

Unlock your full potential with Seneca Premium

  • Unlimited access to 10,000+ open-ended exam questions

  • Mini-mock exams based on your study history

  • Unlock 800+ premium courses & e-books

Get started with Seneca Premium