Copper – Specifications, Properties
Copper is essential for any kind of living. It delivers electricity and clean water into our homes and cities and makes an important contribution to sustainable development. More than that, it is essential for life itself. The following describes different properties of copper, divided by type (chemical, mechanical and physical).
WHAT IS COPPER?
As a chemical element, copper is represented by the symbol Cu in the periodic table and has the atomic number 29. As a metal, copper is ductile and malleable and valued for its high thermal and electric conductivity. Copper occurs naturally but its greatest source is in minerals like chalcopyrite and bornite, and you can easily identify it by its reddish-gold colour.
Copper is produced by massive stars and can also be found in our planet’s crust. The largest mass of copper found weighed a spectacular 420 tonnes!
This element is a key part of human and animal anatomy as well. In humans, copper is typically found in the liver, muscles and bones, with a value of 1.4mg and 2.1mg of copper per kilogram of weight being within normal parameters.
HISTORY OF COPPER
The name of this metal comes from the Old English ‘copper’, which, in turn, derives from the Latin ‘Cyprium aes’, which means ‘metal from Cyprus’.
Copper can be traced back to prehistoric times, as it was known to some of the world’s oldest civilisations. It is believed to have been the first metal to be worked by people (with the earliest use around 9000 BC) since it can be found in relatively pure forms – this means this metal doesn’t necessarily need to be extracted from an ore.
Historically, copper has also been used as pigments, as it was known to add blue or green colours to minerals like azurite and malachite.
This metal was the first to be smelted from its ore (around 5000 BC), the first to be cast into a shape with a mould (around 4000 BC) and the first to be alloyed with tin to create bronze (around 3500 BC).
WHAT ARE THE PROPERTIES OF COPPER?
Copper offers a wealth of properties that make it essential for modern metallurgy – and very useful in a variety of industries and sectors. Some of the most sought-after properties of copper include the following:
- Patina – a green layer of copper sulfate that forms on the surface of the metal due to corrosion; however, this layer is protective and prevents the metal from becoming more deteriorated.
- Corrosion Resistance – this metal is highly resistant to corrosion and copper alloys have been found in near-perfect condition after being buried for millennia.
- Malleability and Ductility – copper is easy to work with, mainly when it comes to fabricating and joining.
- Anti-Bacterial – copper compounds have been used as bacteriostatic agents and fungicides, as well as wood preservatives. This metal’s hygienic properties make it useful to slow down the growth of bacteria like E-coli, legionella and MRSA.
- Strength – copper is a tough metal, and so are its alloys. They don’t shatter or become brittle when exposed to temperatures below 0o
Copper has the best electrical conductivity of any metal, except silver.
A good electrical conductivity is the same as a small electrical resistance. An electric current will flow through all metals, however they still have some resistance, meaning the current needs to be pushed (by a battery) in order to keep flowing. The bigger the resistance, the harder we have to push (and the smaller the current is). Current flows easily through copper thanks to its small electrical resistance, without much loss of energy. This is why copper wires are used in mains cables in houses and underground (although overhead cables tend be aluminium because it is less dense). However, where size rather than weight is important, copper is the best choice. Thick copper strip is used for lightning conductors on tall buildings like church spires. The copper strip has to be thick so that it can carry a large current without melting.
Copper wire can be wound into a coil. The coil will produce a magnetic field and, being made of copper, won’t waste much electrical energy. Copper coils can be found in:
|Electromagnets||Locks, scrapyard cranes, electric bells. (See Electromagnets.)|
|Motors||Pumps, domestic appliances (washing machines, dishwashers, fridges, vacuum cleaners), cars (starter motors, windscreen wipers, electric windows), computers (disc drives, fans), entertainment systems (DVD players). (See Electric Motors.)|
|Dynamos||Bicycles, power stations|
|Transformers||Mains adaptors, electricity substations, power stations. (See Copper and Electricity: Transformers and the Grid.)|