Mind Mapping & Creative Thinking

May 31, 2008

Materials ~ Corrosion & Tarnishing

Filed under: Design Technology — Editor @ 8:07 am

If a metal object is left unprotected it will change. It might be a minimal visual change or it could be a structural change after a period of time.

These changes are called ‘CORROSION’ or ‘TARNISHING’.

Make sure that you are able to understand the different effects that this has on different metals:

Iron and Steels will RUST because they contact IRON.

Rusty Spanner

As you can see on this spanner (which was left outside in the weather) it has started to change from bright shiny metal (steel) to brown rust. It has not taken hold too much because the fine etching of the size of the spanner can be clearly seen just below the jaws.

Rust can be treated and prevented using chemicals.

Some metals become dull when exposed to the air. Silver is a good example of this, you can see on the spoon below it has become dull and ‘tarnished’. The only way to keep the surface shiny is to keep polishing it!

Huge structures like the Eiffel Tower have to be constantly attended to, to ensure that the metal used to make the the tower remain in good condition and structurally sound. A team of city workers constantly check, clean and repaint the tower.

 

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