Properties of Copper
The two main properties of copper that make it indispensable to mankind are its electrical and thermal conductivity but it’s the unique combination of these and other properties that make copper so versatile.
Copper has the highest conductivity of any non-precious metal and one that’s 65% higher than aluminium. This, combined with its high ductility, medium strength, ease of joining and good resistance to corrosion, makes copper the first choice as a conductor for electrical applications. such as cables, transformer and motor windings, and busbars.
Copper is a good conductor of heat (about 30 times better than stainless steel and 1.5 times better than aluminium). This leads to applications where rapid heat transfer is required such as heat exchangers in air conditioning units, vehicle radiators, heat sinks in computers, heat sealing machines and televisions, and as water-cooled furnace components.
Copper is low in the reactivity series. This means that it doesn’t tend to corrode. This is important for its use for pipes, electrical cables, saucepans and radiators. It also means that it is well suited to decorative use. Jewellery, statues and parts of buildings can be made from copper, brass or bronze and remain attractive for thousands of years.
Copper can be combined easily with other metals to make alloys. The first alloy produced was copper melted with tin to form bronze – a discovery so important that periods in history are called The Bronze Age. Much later came brass (copper and zinc), and – in the modern age – copper and nickel. The alloys are harder, stronger and tougher than pure copper. They can be made even harder by hammering them – a process called ‘work hardening’.
Copper can be readily joined by brazing, soldering, bolting or adhesives. In industry, this is very useful for plumbing pipework and joining busbars, which are vital elements of power distribution systems. Elsewhere, it is also an important feature for artists crafting sculptures and statues, and for jewellery makers and other artisans.
Copper is a ductile metal. This means that it can easily be shaped into pipes and drawn into wires. Copper pipes are lightweight because they can have thin walls. They don’t corrode and they can be bent to fit around corners. The pipes can be joined by soldering and they are safe in fires because they don’t burn or support combustion.
Copper is inherently hygienic. Together with durability and aesthetics, this makes copper alloys ideal materials for high touch surfaces in areas where hygiene is a key concern.
Copper and copper alloys are tough. This means that they were well suited to being used for tools and weapons. Imagine the joy of ancient man when he discovered that his carefully formed arrowheads no longer shattered on impact. The property of toughness is vital for copper and copper alloys in the modern world. They do not shatter when they are dropped or become brittle when cooled below 0°C.
Copper is non-magnetic and non-sparking. Because of this, it is used in special tools and military applications.
Copper and its alloys, such as brass, are used for jewellery and ornaments. They have an attractive golden colour which varies with the copper content. They have a good resistance to tarnishing making them last a long a time.
Copper is infinitely recyclable without any loss of properties. Around 40% of Europe’s demand is met from recycled copper.
Copper can act as a catalyst –a substance that can speed up a chemical reaction and improve its efficiency. It does so by reducing the activation energy. Copper speeds up the reaction between zinc and dilute sulfuric acid. It is found in some enzymes, one of which is involved in respiration.
The chemical symbol for copper is Cu, from the Latin ‘cuprum’, meaning from Cyprus, from where the Romans obtained much of their copper.
|Family in Periodic Table||Group 11 (IB)
|Relative atomic mass||63.546|
|Electrical conductivity|| 58.0-58.9 MS/m (m/Ωmm2)
100.0 – 101.5% IACS at 20°C
|Thermal conductivity||3.94 Wcm/cm2 °C at 20°C|