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OpenLearn Live: 4th July 2016

Updated Monday 4th July 2016

What happens when iron meets oxygen.

OpenLearn Live normally updates during the day; unfortunately for technical reasons we lost the 4th July edition. In order to ensure we do a 'full set' of our oxide start-up sequence, though, we're slipping this item back into the set.

Oxide week: Rust

This week, we're celebrating the world of oxides - chemical compounds that consist of oxygen and just one other element. We're going to start off with one of the more familiar oxides - rust.

Rusted boltholes on a tank Creative commons image Icon Dennis Mojado under Creative Commons BY-ND 4.0 license

Rust is iron oxide - and here's a simple explanation of why iron corrodes in the way it does:

This corrosion of metal is obviously hugely damaging to metal-made things, and anything that's damaging will tend to also be expensive. Back in 2000, it was estimated that corrosion cost the US economy USD300million a year; and when you have cars or bridges or builders that are slowly crumbling away, there can be life-threatening risks as well.

There are ways to prevent or slow rust, though:

The latter process is favoured for the Forth Road Bridge. The constant battle between the sea and wind and the bridge meant that the process of rustproofing was never-ending - once the bridge was 'finished', the process needed to be started again. But a new type of paint has - it's hoped - reduced a perpetual task to one only required four times a century. Good news for Sisyphus, who gets to have the 'task that's never finished' metaphor field to himself.

What happens when a bridge fails? Watch The Kinzua Bridge disaster

Try our free course in structural integrity


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