Question 29

Summary: (a) Identify the main metal used to construct ships; explain why aluminium is used in structures exposed to oxidising conditions. (b) Identify a metal commonly used as a sacrificial anode; explain why sacrificial anodes are added to metal-hulled ships. (c) Describe the effect of adding other elements to iron on the properties and uses of steels. (d) Define corrosion;outline a procedure used to compare corrosion rates of different metals or alloys; describe ways accuracy and reliability of the procedure can be improved. (e) Evaluate steps used to clean, stabilise and preserve artefacts recovered from shipwrecks.