Verdigris

The elements of corrosion

Featured in

  • Published 20210129
  • ISBN: 978-1-922212-56-6
  • Extent: 264pp
  • Paperback (234 x 153mm), eBook

COPPER IS AMONG the earliest of metals to be used by humans, and has been smelted, cast and moulded for over ten thousand years. It is also one of the first to be purposefully alloyed with another, so that copper and tin become bronze, and copper and zinc become brass. I’m not sure how I feel about the word ‘alloyed’. It means to mix a fine metal with one less valuable, to debase something by adding something inferior. But which is the finer and which the less valuable? I know that sometimes I feel alloyed.

When exposed to air, copper forms a layer of copper oxide that protects the underlying metal from corrosion. This is clever. Unlike iron, which continues to rust and corrode when exposed to the elements, copper resists corrosion from atmospheric influences. Copper is also incredibly malleable and has a high thermal conductivity. I like both these words: ‘malleable’ and ‘conductivity’. Malleable feels passive and accommodating, soft and comforting. Conductivity is more active and formal, with its hard consonants. In any case, these features mean copper is an excellent conductor of heat and electricity, perfect for the electrical wiring that is used for power generation and transmission, telecommunications and electronic circuitries. An attempt was made at some point to replace copper electrical wiring with aluminium to save money, but buildings caught fire, and so copper was returned and has never been replaced. Other forms of copper wire are essential for electric motors, transformers, inductors, generators, headphones, speaker coils and electromagnets. The world runs on copper wire, which is fine because at today’s rates of extraction there remains five million years’ supply of copper.

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About the author

Lesley-­Anne Houghton

Lesley-­Anne Houghton is a Queensland writer, and has just completed her Master of Arts (Writing and Literature) at Deakin University.

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